26
Correspondence Outreach critical care is not the solution I read with interest the editorial on the Acute Pain Service as a model for outreach critical care (Counsel. Anaes- thesia 2001; 56: 925–6). In our hospital, the Acute Pain Service detected two cases of severe postoperative complications within the last 4 months while reviewing the patient’s analgesia, prompting their return to theatre the same day. However, intensive care nursing resources are already stretched to their limits, and therefore outreach critical care is not the appropriate solution to the problem of inadequate or late initiation of appropriate intensive med- ical treatment at ward level. From my experience in medicine, surgery and Intensive Care, it appears to me that the problems are: doctors are not trained in caring for the critically ill; their consul- tants are often not familiar with critical care issues; their patients are scattered across the hospital; monitoring equip- ment is in short supply on the wards; and nursing staff skilled in monitoring and caring for the acutely ill patient on the ward are in very short supply. As a professional group we should address these issues first. A first step could be to assign doctors to work on a specific ward rather than with a firm. This would make it easier to literally ÔseeÕ the patients, hourly or more often if necessary. Second, training in Acute / Intensive Care should be com- pulsory in all acute specialities at SHO level with an introduction to the subject for all House Officers. Monitoring equipment and nurses skilled in caring for patients who are unwell should not just be available in the Critical Care areas. However, most important is strong leadership from the top. Each and every Consultant should encourage his / her juniors to acquire the know- ledge and the skills needed to work with acutely ill patients in any acute speciality, and give the same positive feedback for caring for an acutely ill patient as for a successful operation or the diagnosis of an uncommon disease. J. Kuehne St. Helier Hospital, Carshalton, UK E-mail: [email protected] Outreach critical care The recent editorial (Counsel. Anaes- thesia 2001; 56: 925–6) rightly stated that ÔComprehensive Critical CareÕ [1] gave little guidance on how an intensive care ÔoutreachÕ service should function. The document was recognition by the Government that something needed to be done to improve the management of the critically ill hospital patient and that current critical care provision is insuffi- cient to meet needs. The stated objec- tives of outreach, averting intensive care unit (ICU) admissions, enabling dis- charges and sharing critical care skills, are undoubtedly important, but are not the only goals. Early identification and enabling critical care admission of appropriate patients is another aim. Clearly there is an overlap between outreach services and acute pain teams. This also applies to other services such as resuscitation and nutrition. Those of us involved in outreach know there are many hospital patients who are not receiving satisfactory care. Acute pain teams, although part of the solution, are not enough. Intensive care outreach has taken many forms from a single nurse, to 24 h, 7 days a week, multidisciplin- ary teams. It is unfortunate that out- reach was introduced without adequate evaluation, but evidence will be forth- coming as the service is established. In the context of the National Health Service, and with the needs of the patient being paramount, it is relevant to ask several questions. These include: why has care on the wards failed, making outside support necessary? Why should critical care units be pro- viding this support? And, will intensive care outreach work without adequate numbers of critical care beds and staff? D. Goldhill A. McGinley The Royal London Hospital, London E1 1BB, UK Reference 1 Department of Health. Comprehensive Critical Care: a Review of Adult Critical Care Services. London: Department of Health 2000. Intensive care costs I was much impressed by the hard work that went into the recent paper ( Jacobs et al. Anaesthesia 2001; 56: 643–7) on the costs of patient care in intensive care unit (ICU). It was plainly a time- consuming and difficult study, which attempted to quantify, probably for the first time, the cost differences between treating very ill patients and less seri- ously ill patients. No doubt their work will prove helpful to those who have to plan critical care services in the future and subdivide critical care beds into high dependency beds and intensive care beds. However, I have one criti- cism of the paper, which relates to the fact that Ônon-patient-specificÕ costs were excluded because they could not be related to individual patients. Whilst this argument may be technically valid, there is always an element of guesswork in calculating the costs of treatment in individual patients in a complex envi- ronment such as an ICU where bed occupancy and staffing levels fluctuate independently of each other and where nurses work flexibly to help each other out. We deceive ourselves if we claim 100% scientific accuracy in such studies. I think it would be reasonable either to divide the Ônon-patient-specificÕ costs equally between the patients, or to Anaesthesia, 2002, 57, pages 183–208 ..................................................................................................................................................................................................................... Ó 2002 Blackwell Science Ltd 183

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Correspondence

Outreach critical care is not thesolution

I read with interest the editorial on theAcute Pain Service as a model foroutreach critical care (Counsel. Anaes-

thesia 2001; 56: 925±6). In our hospital,the AcutePain Service detected twocasesof severe postoperative complications

within the last 4 months while reviewingthe patient's analgesia, prompting theirreturn to theatre the same day.

However, intensive care nursing

resources are already stretched to theirlimits, and therefore outreach criticalcare is not the appropriate solution to

the problem of inadequate or lateinitiation of appropriate intensive med-ical treatment at ward level. From my

experience in medicine, surgery andIntensive Care, it appears to me that theproblems are: doctors are not trained incaring for the critically ill; their consul-

tants are often not familiar with criticalcare issues; their patients are scatteredacross the hospital; monitoring equip-

ment is in short supply on the wards;and nursing staff skilled in monitoringand caring for the acutely ill patient on

the ward are in very short supply.As a professional group we should

address these issues ®rst. A ®rst step

could be to assign doctors to work on aspeci®c ward rather than with a ®rm.This would make it easier to literallyÔseeÕ the patients, hourly or more often

if necessary. Second, training inAcute ¤ Intensive Care should be com-pulsory in all acute specialities at SHO

level with an introduction to the subjectfor all House Of®cers. Monitoringequipment and nurses skilled in caring

for patients who are unwell should notjust be available in the Critical Careareas. However, most important isstrong leadership from the top. Each

and every Consultant should encouragehis ¤ her juniors to acquire the know-ledge and the skills needed to work with

acutely ill patients in any acute speciality,and give the same positive feedback for

caring for an acutely ill patient as for asuccessful operation or the diagnosis ofan uncommon disease.

J. Kuehne

St. Helier Hospital,

Carshalton, UK

E-mail: [email protected]

Outreach critical care

The recent editorial (Counsel. Anaes-

thesia 2001; 56: 925±6) rightly statedthat ÔComprehensive Critical CareÕ [1]gave little guidance on how an intensive

care ÔoutreachÕ service should function.The document was recognition by theGovernment that something needed to

be done to improve the management ofthe critically ill hospital patient and thatcurrent critical care provision is insuf®-cient to meet needs. The stated objec-

tives of outreach, averting intensive careunit (ICU) admissions, enabling dis-charges and sharing critical care skills,

are undoubtedly important, but are notthe only goals. Early identi®cation andenabling critical care admission of

appropriate patients is another aim.Clearly there is an overlap between

outreach services and acute pain teams.

This also applies to other services suchas resuscitation and nutrition. Those ofus involved in outreach know there aremany hospital patients who are not

receiving satisfactory care. Acute painteams, although part of the solution, arenot enough. Intensive care outreach has

taken many forms from a single nurse,to 24 h, 7 days a week, multidisciplin-ary teams. It is unfortunate that out-

reach was introduced without adequateevaluation, but evidence will be forth-coming as the service is established. Inthe context of the National Health

Service, and with the needs of thepatient being paramount, it is relevantto ask several questions. These include:

why has care on the wards failed,making outside support necessary?

Why should critical care units be pro-viding this support? And, will intensivecare outreach work without adequatenumbers of critical care beds and staff?

D. Goldhill

A. McGinley

The Royal London Hospital,

London E1 1BB, UK

Reference1 Department of Health. Comprehensive

Critical Care: a Review of Adult Critical

Care Services. London: Department of

Health 2000.

Intensive care costs

I was much impressed by the hard workthat went into the recent paper ( Jacobs

et al. Anaesthesia 2001; 56: 643±7) onthe costs of patient care in intensive careunit (ICU). It was plainly a time-

consuming and dif®cult study, whichattempted to quantify, probably for the®rst time, the cost differences betweentreating very ill patients and less seri-

ously ill patients. No doubt their workwill prove helpful to those who have toplan critical care services in the future

and subdivide critical care beds intohigh dependency beds and intensivecare beds. However, I have one criti-

cism of the paper, which relates to thefact that Ônon-patient-speci®cÕ costswere excluded because they could not

be related to individual patients. Whilstthis argument may be technically valid,there is always an element of guessworkin calculating the costs of treatment in

individual patients in a complex envi-ronment such as an ICU where bedoccupancy and staf®ng levels ¯uctuate

independently of each other and wherenurses work ¯exibly to help each otherout. We deceive ourselves if we claim

100% scienti®c accuracy in such studies.I think it would be reasonable either todivide the Ônon-patient-speci®cÕ costsequally between the patients, or to

Anaesthesia, 2002, 57, pages 183±208.....................................................................................................................................................................................................................

Ó 2002 Blackwell Science Ltd 183

Page 2: Just who do they think we are?

devise a formula whereby these costs arecalculated according to the daily cost ofeach patient's care, so that the patientswho receive more input of care bear a

larger proportion of the Ônon-patient-speci®cÕ costs. The cost of utilities,which includes such items as power,

heating, water, the fabric of the build-ing, portering, cleaning, waste disposal,medical gases and suction, is substantial

and I suspect, often underestimated. Onour 6-bedded ICU, in the year 1999±2000, we paid £340 000 per annum for

utilities. This represented £237 perpatient day, or 20% of the mean totalcost of a patient day, which was £1184(excluding capital expenditure on re-

placement of equipment (Table 1).There is the danger that the true cost

of critical care will be underestimated if

papers of this kind exclude Ônon-patient-speci®cÕ costs and that this maylead to subsequent under funding of our

specialty.

W. Konarzewski

Colchester General Hospital,

Colchester CO4 5JL, UK

A reply

We are glad to have the opportunity

of replying to the letter fromDr Konarzewski. He is factually correct

in saying that the non-patient-speci®ccosts were excluded from this study. Weagree it may have been more appropri-ate to include the non-patient-speci®c

costs as we are persuaded by the argu-ment that the work may be misinter-preted as representing the total costs of

patient care. The aim of the study was,however, to identify factors that couldexplain the variation in average daily

costs between individual patients. It wasfor this reason, given the assumptionthat individual patients consume equal

quantities of these non-patient-speci®ccosts on a daily basis, that they wereexcluded. He is correct in thinking thatnon-patient-speci®c costs are substantial

and although dif®cult to measure andassign to different clinical areas, can beas high as 50% of the total costs.

Arbitrary methods of allocating thesecosts at a hospital level down to theintensive care unit (ICU) can also

explain why one hospital would havesigni®cantly higher non-patient-speci®ccosts, than others. It would, however, be

relatively simple to derive an averagenon-patient-speci®c cost per patient andaccept that the variation in total non-patient-speci®c cost between individual

patients would merely be as a function oftheir length of stay. On the other hand,apportioning costs on the basis of Ôinput

of careÕ, i.e. producing some kind ofweighting system according to howmany patient-speci®c resources are used,would be in our view, interesting but

quite dif®cult. The dif®culty lies in thatsome of the non-patient related costswould be a function of their Ôinput of

careÕ; however, others would not.We would suggest that whilst it is not

ideal we will, in future, add the non-

patient speci®c costs of care. We thankhim for his comments.

C. Hibbert

D. Edbrooke

Royal Hallamshire Hospital,

Shef®eld S10 2JF, UK

E-mail: [email protected]

Cricoid pressure application byintensive care nurses

Dr Matthews points out that some staffwho assist anaesthetists by providing

cricoid pressure, including intensivecare nurses, may not be adequatelytrained in the technique (Matthews.

Anaesthesia 2001; 56: 915±17). In con-trast to practice in the operating the-atre, the assistant for rapid sequenceinduction (RSI) on the intensive care

unit (ICU) is usually a nurse who has avery different training background tothat of an operating department prac-

titioner. The English National Board(ENB) regulates the curriculum for theAdult Intensive Care Course (ENB

100) for nurses. The ENB 100 syllabusdoes not mention RSI or cricoidpressure and there are regional incon-

sistencies in the teaching of skills andprocedures in the ENB 100 courseaccording to local interpretation of thesyllabus [1]. As a result, a nurse on the

intensive care unit may not have beentaught this skill. An inadequatelytrained assistant may put patients at risk

through failure to protect the airwayadequately or by making laryngoscopyand intubation more dif®cult. Ad hoc

training at the time of emergencyintubation is not satisfactory and is nosubstitute for formal training and reg-

ular refreshment of the skill [2]. Thepractice of cricoid pressure and assistingwith RSI should be included in theENB 100 course so that practice of this

Table 1 Annual cost of running ICU 1999±2000.

Total annualcost

Percentageannual cost

Costpatient.day)1

Nursing staff (regular) £624 672 37% £436Utilities £340 000 20% £237Drug costs £162 689 10% £114Disposables £110 551 7% £77Nursing staff (agency) £89 596 5% £63Laboratory services £88 556 5% £62Medical cover (non-consultants) £75 700 4% £53Blood products £61 049 4% £43Regular consultant sessions £39 600 2% £28Radiology £24 634 1% £17Special beds £22 038 1% £15Technician (MTO3) £21 109 1% £15Nutrition £15 500 1% £11Physiotherapy £11 138 1% £8Ward secretary £9171 1% £6

Number of patient days � 1433.Bed occupancy � 65%.Annual cost of ICU* £1 696 003.Cost per patient.day)1* £1184.*Excludes capital expenditure on replacement of equipment.

Correspondence Anaesthesia, 2002, 57, pages 183±208......................................................................................................................................................................................................................

184 Ó 2002 Blackwell Science Ltd

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procedure in the ICU is consistent withthat in the operating theatre.

E. P. Segar

Hospital for Sick Children,

Toronto M5G 1 X8, Canada

E-mail: [email protected]

References1 Endacott R, Scholes J, Chellel A. Bal-

ancing stakeholder needs. A review of

ENB 100 and 415 courses. Intensive and

Critical Care Nursing 2000; 16: 3±13.

2 Segar EP, Boulanger CM, Davies AF,

Allman KG. Knowledge and skill of

cricoid pressure application by intensive

care nurses: is formal training beneficial?

Intensive Care Medicine 2001; 27: S290.

Cardiac output determinationusing compliance

Measurement of the compliance of thearterial system may provide the key forobtaining cardiac output by using this

compliance in combination with a cal-ibrated arterial waveform. Arterial com-pliance has been dif®cult to measure, so

that normal and pathological values arenot available to the clinician, andchanges occurring during most surgicaloperations are unrecognised. Interest in

endothelial vasomotor function and thepart played by nitric oxide have led toinvestigations of methods of measuring

these changes [1]. Of particular interestis the measurement of pulse wavevelocity [2], which is also a means for

deriving compliance [3], as pulse wavevelocity is inversely proportional tocompliance and can be measured by a

non-invasive method. As a calibratedarterial waveform can also be obtainedby non-invasive methods, the abilitynow exists to combine the two systems

to continuously monitor cardiac outputby non-invasive means. Periodic com-pliance estimations will ensure that

appropriate corrections are made forvasomotor changes.

Compliance is a measure of volume

change against unit pressure change. Bymultiplying the pressure scale of acalibrated arterial waveform by the

compliance, the display becomes vol-ume change plotted against time. The

rate of this volume change is ¯ow. Afterthe dicrotic notch (indicating aorticvalve closure) the arterial pressure fallsexponentially as the arterial system

empties. The position of mean arterialpressure on this curve is also the posi-tion of mean arterial ¯ow leaving the

arterial system. This equals mean ¯owrate into the arterial system, whichequals cardiac output. Time measure-

ment taken as a tangent to the curve atmean arterial ¯ow determines this ¯owrate. As this time is the time constant, it

may be measured at any convenient partof the exponential curve[4], not neces-sarily at the mean arterial pressure levelwhere interference around the dicrotic

notch may exist. The relationship isrepresented by the equation:

Cardiac output

� Mean arterial pressure � Compliance

Time constant

Con®rmation of this relationship isobtained by combining two acceptedformulae:

a Mean arterial pressure� Cardiac output ´ Systemic vas-

cular resistance [5].

b Compliance ´ Resistance� Time constant [6].

So that: Systemic vascular resistance

� Time constant

Compliance

Substituting this product in formula[a] gives:

Mean arterial pressure

� Cardiac output � Time constant

Compliance

This confirms: Cardiac output

� Mean arterial pressure

� Compliance

Time constant

A programmed lap top computer orequivalent is capable of analysing andcomputing information derived from a

calibrated waveform together with theinformation from compliance measure-ment, averaging the results over a

period of about 20 s (to smooth outvariations in stroke volume and heartrate) and displaying the results. The

eventual display could therefore includeindependent values for cardiac output,stroke volume, peripheral resistance,compliance, and as well, a continuous

display of the calibrated arterial wave-form.

This is an oversimpli®cation of a

method for deriving cardiac outputby non-invasive means. It has not pre-viously been suggested but is an exciting

possibility, which should be investigated.The value to anaesthetists and manyother clinicians would be immense.

D. I. Campbell

Sydney, Australia

References1 Doshi SN, Lewis MJ, Goodfellow J.

Improving endothelial vasomotor

function. British Medical Journal 2001;

323: 352±3.

2 Naka KK, Doshi SN, Ashton M,

Frenneux MP, Jones CJH,Goodfellow J.

Changes in pulse wave velocity in large

arteries are nitric-oxide mediated.

European Heart Journal 2000; 21: 357.

3 Kelman GR. Cardiovascular measure-

ments. Applied Cardiovascular Physiology.

Butterworths, Sydney 1971, 231.

4 Parbrook GD, Davis PD, Parbrook EO.

Natural exponential functions. Basic

Physics and Measurement in Anaesthesia,

3rd edn. Butterworth-Heinemann,

Oxford 1990, 68±72.

5 Ganong WF. Dynamics of blood and

lymph flow. Review of Medical Physiolog,

15th edn. Prentice Hall, Sydney 1991,

536.

6 Nunn JF. Elastic forces and lung

Volumes. Applied Respiratory Physiolog,

3rd edn. Butterworths, Sydney 1987, 43.

Manpower requirements whenimplementing a partial shiftsystem for anaesthetic juniors

The New Deal for trainee doctors setslimits to the duration and intensity ofwork junior doctors should do. Many

anaesthetic juniors' working patternsbreach the New Deal [1]. In an attemptto ensure compliance, many Trusts are

considering or switching to the partialshift system for anaesthetic juniors. How-ever, signi®cant manpower increases are

Anaesthesia, 2002, 57, pages 183±208 Correspondence......................................................................................................................................................................................................................

Ó 2002 Blackwell Science Ltd 185

Page 4: Just who do they think we are?

needed for proper implementation of thepartial shift system. The needed increasesmay be calculated.

Under the partial shift system, each

24-h on-call period is split between twotrainees per on-call tier. There willtherefore be 24 man-hours needed per

day and 7 ´ 24 � 168 man-hours perweek just for the on-calls for each tier.With n trainees per tier, the number

of hours worked per week per traineejust for on-calls, is 168 ¤ n (Handovertime is not included and may need to be

separately factored for lengthy hand-overs, e.g. ITU). In addition, RoyalCollege training guidelines requires aminimum of three accompanied lists per

week per trainee [2]. At 4 per list(including shared pre-operative visits),each trainee will need to work at least

another 12 h per week in addition tothe on-calls. With a maximum limit of64 h per week, the number of hours

worked per trainee is given by theequation 12 + 168 ¤ n < 64.

However, it is expected that trainees

will also do x number of other lists,accompanied and unaccompanied. At4.5 h per list (including pre-operativevisits), this adds up to another 4.5x

man-hours per trainee. Therefore, theequation above becomes 4.5x +12 + 168 ¤ n < 64. Rearranging, n >

168 ¤ (64 ) 12 ) 4.5x).Each trainee is also entitled to

5±6 weeks' annual leave and 6 weeks'

(28 days') study leave, which makes apossible 11±12 weeks' leave per trainee.Therefore, over the entire year, anadditional 11 ¤ 52±12 ¤ 52 doctors is

needed per trainee for prospectivecover. Therefore, the ®nal formulashould be:

n> 168��1�11=52�=�64ÿ12ÿ4:5x�:Note, however, that mixing trainees

and non-trainees on each on-call tier

may reduce the additional fraction ofdoctors needed for prospective cover, asnon-trainees tend to have less study

leave entitlement than trainees. Theaveraged leave entitlement per doctorshould then be used in the formulaabove. The value of n may thus be

calculated from the corresponding valueof x (Table 2). It is evident fromTable 2, that the number of lists each

trainee should do, in addition to theminimum training three lists, is criticallylimited by the number of trainees oneach on-call tier.

Some generalisations have beenmade. Each department should there-fore adjust the calculations for their

particular circumstances. Nevertheless,it is apparent that many Trusts will havedif®culty implementing the partial shift

system without trainee expansion. Sincetrainee expansion is centrally controlled,perhaps other options more amenable tolocal control, such as consultant or non-

consultant career grade expansion, orrationalizing anaesthetic commitments,should also be considered when plan-

ning for partial shift.The formula may be adapted for

expected changes to consultant work

patterns, with the imminent coming-into-force of the European Work TimeDirective and increasing clinical,

administrative, supervisory and teachingworkloads.

M. Lim

Northampton General Hospital

Northampton NN1 5BD, UK

E-mail: [email protected]

AcknowledgementsI acknowledge the help of Dr JanSzafranski, College Tutor, Kettering

General Hospital and Dr Jill White,Clinical Director, Northampton Gen-eral Hospital, in writing this letter.

References1 Department of Health Internet publi-

cation March 2001 http://www.doh.-

gov.uk/juniordoctors/compliance.htm

2 Royal College of Anaesthetists publi-

cation. Guidance for Trainers; Issue 5 June

2001.

Probability of winning theNational Lottery

I read with great interest the reviewarticle on risk perception and commu-

nication: recent developments andimplications for anaesthesia (Adams &Smith. Anaesthesia 2001; 56: 745±55).

The topic is indeed a confusing one andmany concepts are dif®cult to graspeven for health professionals. The gen-

eral public would be expected to ®ndthe subject even more confusing. Whenit comes to the National Lottery how-ever, their knowledge of risk seems

slightly better than one would expect.Indeed a signi®cant proportion of thepopulation are aware that the chance of

winning the jackpot is somewhere inthe region of 14 million to one against.This ®gure is far greater than the 2.8

million to one quoted in the aforemen-tioned review.

On closer inspection, it appears that

all the ®gures quoted in Table 2 of thereview are incorrect. Additionally, theauthors incorrectly quote the odds ofobtaining four balls plus the bonus ball.

This is an irrelevance anyway, as thissituation does not produce a prize anygreater than obtaining four balls alone.

With this in mind, I believe Table 3should read as follows (please refer toTable 3):

M. Fair®eld

Leicester, UK

E-mail: mfair®[email protected]

A reply

We would like to thank Dr Fair®eld for

his constructive comments and theEditor for offering us the opportunityto correct those errors that have been

brought to our attention since thepublication of our review article. Onreviewing our original source [1] that

provided the National Lottery proba-

Table 2 The relationship between x thenumber of lists (over the minimum threetraining lists) each trainee should do, and nthe minimum number of trainees peron-call tier. Since we cannot have frac-tions of trainees, the ÔrealÕ number oftrainees needed per on-call tier is given inthe rightmost column.

x n

'Real' numberof traineesneeded

0 3.91 41 4.29 52 4.73 53 5.29 64 5.99 65 6.90 76 8.14 97 9.93 10

Correspondence Anaesthesia, 2002, 57, pages 183±208......................................................................................................................................................................................................................

186 Ó 2002 Blackwell Science Ltd

Page 5: Just who do they think we are?

bility data for Table 2, we should havereported that the probabilities quotedwere for a £5 stake. Hence the prob-ability data in our table differ by a factor

of 5 from that quoted by M. Fair®eldabove. We therefore agree that theprobability of predicting six balls in

the National lottery is 1 in 13 983 16and this correctly represents the odds fora £1 stake.

It has also been brought to ourattention that the risk ladder on p. 749quotes the risk of death from anaes-thesia as given in the ÔReport on

Con®dential Enquiries into MaternalDeaths for the years 1988 and 1990Õ [2]as 1 in 58 823. The correct ®gure is in

fact 1 in 588 235 as implied in thetext. We have therefore taken thisopportunity to revise the Risk Ladder

(Fig. 1), correcting the above errors aswell as amending the orientation of thelogarithmic graph lines that were

inverted.We regret that these errors occurred,

however, we feel they further emphas-ise the dif®culties inherent in ®nding,

interpreting, and presenting risk infor-mation in a user-friendly form, even forsupposedly numerate anaesthetists such

as ourselves!

A. M. Adams

A. F. Smith

Royal Lancaster In®rmary,

Lancaster, UK

E-mail: Andrew.Smith@

l.baytr.nwest.nhs.uk

References1 Barclay P, Costigan S, Davies M. Lot-

tery can be used to show risk [Letter].

British Medical Journal 1998; 316: 124.

2 Department of Health. Report

on Con®dential Enquiries into Mater-

nal Deaths in the United Kingdom,

1988±1990. London: The Stationery

Of®ce 1994.

Anaesthesia induction rooms ±sheer luxury

Dr Sawyer's experiences in Canadaeasily translate to the UK (Sawyer.

Anaesthesia 2001; 56: 1006). I aban-doned the use of anaesthetic rooms in1993. Inducing anaesthesia, then dis-connecting all monitoring and the

breathing system, and taking the patientfor an apnoeic perambulation on asightseeing tour of the theatre suite is

frankly barmy, if not downright haz-ardous. Objectively, if we indulge thispractice, we could be accused of pan-

dering to personal insecurity, or worse,some form of professional narcissism.What is the point of establishing min-

imum standards of monitoring, teachingour trainees that failure to adhere to

Figure 1

Table 3 Two different methods of conveying National Lottery probability data.

Balls correct

3 balls 1 : 57 1754 : 100 0004 balls 1 : 1032 96 : 100 0005 balls 1 : 55 491 1.8 : 100 0005 balls + bonus ball 1 : 2 330 636 0.043 : 100 0006 balls 1 : 13 983 16 0.0072 : 100 000

Anaesthesia, 2002, 57, pages 183±208 Correspondence......................................................................................................................................................................................................................

Ó 2002 Blackwell Science Ltd 187

Page 6: Just who do they think we are?

these standards is a cruci®xion offence,then encouraging the baf¯ed trainee tosuspend disbelief while we disregard allthe rules and move the patient to the

substantive anaesthetic venue?Inducing anaesthesia in theatre is in

my experience safer, faster, and allows

plenty of space for inserting lines with-out desterilizing the equipment in acramped anaesthetic room. Moreover,

after only a very short time, the sur-geons were re-educated into not inter-fering with the patient until prepared

for surgery. Indeed, many of the surgi-cal trainees took to observing themysterious rites of anaesthesia with agrowing fascination, understanding, and

dare I say it, respect? Several have sinceapproached me for airway and ÔlinesÕtraining, so I guess they must have

enjoyed the anaesthetic ¯oorshow.Several interesting spin offs have

bene®ted patients. One unfortunate

who suffered an anaphylactic reactionat induction owes his survival(unscathed) to the ready presence of

plenty of pairs of hands, best equipment,monitoring and space that in-theatreinduction afforded. Moreover, I enjoysharing my disasters with the rest of the

team ± it is less stressful, not morestressful, and has led to more referrals ofanaesthetic pre-assessment.

The resource released by not havingto equip anaesthetic rooms could beused for something of value: critical care

beds, nurses to staff them and so on.Surely, in the interest of safety it is timeto have a little more con®dence in ourprofession, and emerge from the anaes-

thetic room into the daylight world ofthe operating theatre.

M. Bellamy

St James's University Hospital,

Leeds LS9 7TF, UK

E-mail: [email protected]

Compartment syndrome

We were interested to read the recentpaper (Turnbull & Mills. Anaesthesia

2001; 56: 980±7) describing three casesof compartment syndrome associatedwith the Lloyd Davies position. They

are to be congratulated on their exten-sive review of the literature. Althoughthey accept that epidural analgesia mayresult in hypotension and may reduce

perfusion in the elevated limb, theyfurther comment that this does notmask the signs of compartment syn-

drome. However, this reduction inblood ¯ow in the limb may be acausative factor in compartment syn-

drome. The three cases they describe allhad epidural analgesia, as did the patientreferred to in ref. 24 [1]. A further case

of bilateral compartment syndrome hasbeen reported by Tuckey [2], whichalso involved epidural analgesia. We areaware also of a medico-legal case when

prolonged urological surgery with epi-dural analgesia resulted in compartmentsyndrome.

We have both been on the staff ofSt Mark's Hospital, a hospital specializingin lower abdominal surgery, for more

than 25 years during which time we haveperformed several thousand operations inthe Lloyd Davies position. No patients

had epidural analgesia and we are able toreport that none of these patients devel-oped compartment syndrome. Prior tooperating, the surgeon always checked

the position of the patient on the table toensure there was no compression orundue strain on the legs. Furthermore,

care was taken to ensure that the secondassistant with the tiresome task of pullingon the retractor for many hours while

standing between the patient's legs didnot compress the legs as he tired.

Prior to the adoption of the LloydDavies position, patients having lower

abdominal surgery, and in particularabdomino-perineal resection of the rec-tum, had the operation in three stages.

Initially, the patients were supine whenthe abdomen was opened to assess theoperability of the tumour. The patients

were then turned on their side whenthe rectum was excised and ®nallyreturned to the supine position for

closure of the abdomen. The adoptionof the Lloyd Davies position obviatedthe need for these procedures andreduced morbidity.

Turnbull & Mills quite correctly referto the original paper by Mr LloydDavies [3] but the diagram they have

produced is incorrect as is their ref. 25.

The buttocks should be in line with theend of the table; likewise the clampholding the stirrups is shown almostmidway up the table when in fact it

should be held at the end of the table.The legs are not strapped but heldloosely on the calf rest and secured by

velcro straps. Mr Lloyd Davies replacedthe sandbags under the sacrum with abeanbag. Shoulder rests were initially

used but were dispensed with when thenon-slip mattress was introduced. Nocases of brachial plexus palsy were noted

as the arms were placed by the patient'sside.

We both worked with Mr LloydDavies who was a slow but meticulous

surgeon. He had been known to takeup to 12 h for a complicated majorsurgical procedure and compartment

syndrome was conspicuous by itsabsence.

L. Kaufman

P. R. Hawley

London, UK

E-mail: [email protected]

References1 Goldmsith AL, McCallum DID.

Compartment syndrome as a compli-

cation of prolonged use of the Lloyd

Davies position. Anaesthesia 1996; 51:

1048±52.

2 Tuckey J. Bilateral compartment syn-

drome complicating prolonged lithot-

omy position. British Journal of

Anaesthesia 1996; 77: 546±9.

3 Lloyd Davies OV. Lithotomy-Tren-

delenburg position for resection of

rectum and lower pelvic colon. Lancet

1939, 74±6.

Obstruction of airwayequipment

We would like to report an interestingreason for an obstructed pattern ofbreathing during a general anaesthetic.A laryngeal mask airway was inserted

after induction of anaesthesia in an ASAII patient. Despite an easy insertion andadequate depth of anaesthesia, the

respiratory pattern appeared obstructed.The capnograph trace con®rmed theclinical picture. The situation was not

Correspondence Anaesthesia, 2002, 57, pages 183±208......................................................................................................................................................................................................................

188 Ó 2002 Blackwell Science Ltd

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improved by a jaw lift, so the laryngealmask airway was removed. At no time

did the patient desaturate. On removalof the laryngeal mask, a foreign bodywas noted. Figure 2 shows the laryngeal

mask airway with a black bung within it(arrow). This was in fact the pneumaticseal of a Rusch facemask. This equip-

ment dysfunction highlights twoimportant principles: the need to alwayscheck the patency of airway devices and

to remove an airway device if thebreathing pattern appears obstructeddespite simple airway manoeuvres.

D. Cameron

J. Onslow

Royal Perth Hospital,

Perth 6847, Western Australia

Another airway foreign body

An ASA III, slightly overweight,68-year-old woman presented forvaricose vein surgery. She suffered from

mild pulmonary insuf®ciency. She wasinduced with increments of propofol to150 mg, and a laryngeal mask inserted.

She did not settle, and was given afurther 50 mg propofol. Since she wassalivating profusely, the mask was with-

drawn again, her pharynx cleared usinga Yankauer sucker, and the laryngealmask reinserted. She started coughing

persistently, and eventually was givenatracurium 30 mg and intubateduneventfully. At the end of surgeryshe was extubated. She again started

coughing, and then spat out a small

piece of clear ¯exible plastic (Fig. 3).The waste bin was searched, and a piece

was discovered to be missing from theinner wrapping of the Yankauer suckermatching the piece spat out (Fig. 4).

This case demonstrates that a foreignbody may be introduced inadvertentlyinto the airway from ÔbenignÕ sources.

On this occasion it was a piece ofwrapping plastic, which had threeproperties that may have led to this

incident:1 It was transparent so that the suckerthat it wrapped could be seen, buttherefore inconspicuous and unnoticed

when the patient was intubated.

2 It was electrostatic and so may haveÔstuckÕ to the sucker when the coverwas pulled off.3 It curled on stretching and therefore

may have wrapped itself around thesucker, rendering itself less conspicuous.

The electrostasis and curling were

demonstrable by testing later. Therewere other potential problems relatingto this type of plastic:

1 The plastic is radiolucent and ifinhaled would not have shown up onX-ray.

2 If it were sticking to the sidewall of abronchus, it would be dif®cult to see.

We need to package equipment so asto prevent contamination, but the

packaging itself must be designed toensure that it cannot cause problems.

J. A. Lack

Salisbury Hospital,

Salisbury SP2 8BJ, UK

E-mail: [email protected]

Yet another foreign body in alaryngeal mask airway

The laryngeal mask airway is a commonmethod of securing the airway dur-ing elective and some emergency

Figure 2

Figure 3 Figure 4

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Ó 2002 Blackwell Science Ltd 189

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operations. I would like to report aforeign body that I came across in asterile packed laryngeal mask airway,which could have had serious conse-

quences. Figure 5 shows the laryngealmask in question. The foreign body isapparently one of the cleaning rods that

are used to decontaminate the laryngealmask airway (Fig. 6). One of the clean-ing rods had accidentally come loose

and lodged itself in the laryngeal mask.Foreign bodies in laryngeal masks

have been reported previously [1, 2].The importance of inspection of the

laryngeal mask airway visually bothinside and outside cannot be over-emphasised.

K. Srikanth

Burnley General Hospital,

Burnley BB10 2PQ, UK

E-mail: [email protected]

References1 Riley RH, Browning FS. Another

foreign body in a LMA. Anaesthesia

1996; 51: 286±7.

2 Conacher ID. Foreign body in a

laryngeal mask airway. Anaesthesia

1991; 46: 164.

An unexpected complicationresulting from the use of alaryngeal mask during anoperation to remove a branchialcyst

A 42-year-old lady presented to thedepartment of Oral and Maxillofacial

surgery at Worthing hospital with a5-year history of a painless lump in theleft side of her neck. Examinationrevealed a mobile, ®rm, elongat-

ed, 4 ´ 3 ´ 2 cm ovoid mass in the leftjugulodigastric region. Subsequent, ®neneedle aspiration and CT scanning

con®rmed the presence of a branchialcyst. On admission, the position of thecyst was marked on the skin. Once

anaesthetised, the patient was placed ina Ôhead upÕ position, with the headextended and turned to the right. The

mass was palpated again and a skincrease incision co-inciding with thepre-operative skin marking was select-ed. Dissection proceeded through plat-

ysma and the anterior border ofsternomastoid was de®ned. As the con-nective tissue over the presumed cyst

was opened, whilst still in a verysuper®cial plane, both surgeons weredisconcerted by the unmistakeable ap-

pearance of the laryngeal mask coveredby strands of middle constrictor andpharyngeal mucosa (Fig. 7). At thispoint, on discussion with the anaesthe-

tist, it was agreed that the laryngealmask should be exchanged for a trachealtube. Prior to this manoeuvre, stay

sutures were placed in the edges of thepharyngeal defect to facilitate subse-quent closure. The wound was then

covered with damp gauze, the tubeswere exchanged and the area re-draped.With the removal of the laryngeal mask,

the branchial cyst dropped back into theoperative ®eld (Fig. 8). The laryngealmask had evidently displaced the cystsuperiorly so that it lay deep to the edge

of sternomastoid. The removal of thecyst proceeded uneventfully, and thepatient made an uneventful recovery.

The patient was fully informed of thecomplication postoperatively and hassince been discharged back to the care

of her GP.The use of laryngeal masks in head

and neck surgery has become common

in the last 10 years. Complicationsassociated with the use of such airwaysare well recognised. However, ourliterature search has failed to reveal any

complication similar to the one des-cribed above. Despite the fact that theoperation involved a consultant anaes-

thetist, consultant Maxillofacial surgeonand a ®nal year specialist registrar, all ofwhom were cognizant of the anatomic

distortion produced by laryngeal masks,this complication still occurred. Theauthors urge caution when using such

airways when removing neck lumps.

A. W. Wilson

D. Macpherson

V. Santhanam

St Richards's Hospital,

Chichester PO19 4SE, UK

E-mail: [email protected]

R. Edwards

Worthing Hospital,

Worthing BN11 2DH, UK

A phantom capnograph trace

End tidal carbon dioxide (FE¢CO2) mon-

itoring is an essential monitor foranaesthetic safety [1]. Sudden disappear-

Figure 5

Figure 6

Figure 7 Figure 8

Correspondence Anaesthesia, 2002, 57, pages 183±208......................................................................................................................................................................................................................

190 Ó 2002 Blackwell Science Ltd

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ance of the capnograph waveform isone of the earliest indicators of patientdisconnection from the breathing cir-cuit. We would like to report a cir-

cumstance in which disconnection maygo undetected during spontaneousbreathing by capnograph alone.

In our hospital, we routinely usecircle systems (Bleasorb) with low ¯ow(< 2 L.min)1), to conserve anaesthetic

gases. The gas sample for the side streamcapnograph is drawn from the Y con-nector and returned to the circle system

just proximal to the expiratory one-wayvalve through a ®lter. After a routinegeneral anaesthetic for orthopaedic sur-gery with low ¯ow and spontaneous

breathing, the sevo¯urane and nitrousoxide were turned off and oxygen wascontinued at 1 L.min)1, to allow plas-

tering and smooth emergence fromanaesthesia. When the patient was tobe transferred to the trolley, the breath-

ing system was disconnected from thelaryngeal mask. To our surprise therewas a continued capnograph waveform

with a rate of 8.min)1 and an FE¢CO2 of3.5 kPa. The apnoea alarm, which wasset at 3 kPa, was not triggered evenafter 150 s. This waveform continued

for more than 3 min. Careful observa-tion of the circle system revealed rhyth-mic movement of the reservoir bag and

the inspiratory unidirectional valve,which coincided with the inspiratorypart of the phantom waveform. The

phantom rate increased with increasingfresh gas ¯ow, along with a reduction inthe FE¢CO2 value, and the reverseoccurred with a decrease of the fresh

gas ¯ow. The capnograph trace disap-peared with disconnection of the sam-ple return tube and reconnecting it

distal to the expiratory unidirectionalvalve near the reservoir bag.

The return of the capnograph sample

gas to the expiratory limb of the circlesystem at the rate of 200 ml.min)1

resulted in reverse ¯ow of expired CO2

from the expiratory limb. This wasintermittently interrupted by fresh gas¯ow. The low fresh gas ¯ow intermit-tently opened the inspiratory valve

when the pressure in the proximalcompartment was suf®cient to lift thediaphragm. This resulted in intermittent

sampling of fresh gas and previously

expired gas resulting in a square wavecapnograph trace. The re-circulation ofsample gas at 200 ml.min)1 prolongedthe capnograph trace for more than

3 min.The phantom square wave capno-

graph after disconnection was reported

during positive pressure ventilation witha Servo 900C ventilator by Ginosar andBaronav [2]. This was explained as due

to continuous reverse ¯ow of previouslyexpired gas from the expiratory tube,intermittently interrupted by the

attempted positive pressure ventilation.Disconnection during positive pressureventilation may be detected earlier thanwith the spontaneously breathing

patient as a low airway pressure alarmgives additional safety.

We suggest connecting the sample

return tube between the expiratoryvalve and the absorber in the circlesystem and extra vigilance is required

during low ¯ow anaesthesia to preventdisconnection.

Girish

T. M. W. Long

South Warwickshire General Hospital,

Warwick CV34 5BW, UK

References1 Recommendations for Standards of Moni-

toring During Anaesthesia and Recovery.

The Association of Anaesthetists of

Great Britain and Ireland, 2000,

London.

2 Ginosar Y, Baranov D. Prolonged

ÔphantomÕ square wave capnograph

tracing after patient disconnection or

extubation. Potential hazard associated

with the Siemens Servo 900c ventilator.

Anesthesiology 1997; 86: 729±35.

Phantom anaesthetic vapour

We describe the unusual detection ofdes¯urane in the breathing circuit (cir-cle system) by the Hewlett Packard(HP) Anaesthetic Gas Monitor (AGM)

M1062A when set to automatic agentdetection mode during general anaes-thesia for hysterectomy in an adult

female patient. All HP AGMs in thishospital were set to automatic agentdetection mode by default. For the ®rst

patient on the list, the HP AGM wasmanually set to detect sevo¯urane dur-ing an anaesthetic that involved thepatient spontaneously breathing sevo-

¯urane in a nitrous oxide ¤ oxygen mix-ture through a circle rebreathing circuit.At the conclusion of the procedure, the

sevo¯urane vaporiser was turned off andthe fresh gas ¯ow through the breathingcircuit was stopped. The following

patient was scheduled for a total hyster-ectomy under general anaesthesia.Intravenous induction was followed by

maintenance with iso¯urane in nitrousoxide and oxygen. The HP AGMdetected des¯urane in the breathingcircuit instead of iso¯urane. An imme-

diate check of the anaesthetic machinecon®rmed the absence of a des¯uranevaporiser on the machine. Checking of

the HP AGM revealed that it was on theautomatic agent detection mode. Theproblem persisted for approximately

5 min before the HP AGM correctlyidenti®ed iso¯urane.

The HP AGM identi®es anaesthetic

vapour by infrared absorption [1]. In theautomatic agent detection mode, itidenti®es the vapour with the highestconcentration and measures its concen-

tration. It has four ®lters in the range of10±14 lm. The ®rst, third and fourth®lters have different absorption peaks

for iso¯urane, halothane and en¯urane[1]. The second ®lter acts as the refer-ence since the above-mentioned anaes-

thetic vapours have similar absorptionpeak at 10.6 lm [1]. However, the HPAGM has similar absorption peaks forsevo¯urane and des¯urane [1]. Because

of this limitation, the HP AGM is pre-programmed to detect one agent bydefault in the automatic agent detection

mode; this may be sevo¯urane ordes¯urane. In this hospital, all the HPAGMs are programmed to detect

des¯urane in the automatic agentdetection mode. Hence the detectionof des¯urane in the breathing circuit at

the start of the second patient's anaes-thetic. The reason for this decision isunknown to us.

The unusual detection of des¯urane

occurred because the HP AGM was setto automatic agent detection mode. Atthe conclusion of the ®rst case, there

was residual sevo¯urane in the

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Ó 2002 Blackwell Science Ltd 191

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breathing circuit. Furthermore, theremay not be enough time for adequate¯ushing of the breathing circuit prior tothe start of the next anaesthetic. At the

beginning of the second case, the con-centration in the breathing circuit ofsevo¯urane compared to iso¯urane was

much higher; this lead to the wrongidenti®cation of des¯urane by the HPAGM. With continued ventilation, the

iso¯urane concentration in the breath-ing circuit subsequently built up and theHP AGM then correctly identi®ed

iso¯urane as the anaesthetic agent inuse. We suggest that when using the HPAGM, the selection of anaesthetic agentdetection mode be set manually instead

of being left on the automatic agentdetection mode. We also reiterate thatwith the use of a circle rebreathing

circuit, it should be ¯ushed throughwith oxygen to void the anaestheticvolatile agent prior to the start of

anaesthesia for the next patient [2]. Thiswill avoid the situation of wronglyidentifying another anaesthetic agent

from the one being used.

D. Kang

N. C. Hwang

Singapore General Hospital,

Singapore

References1 HP Component Monitoring System User's

Reference Manual: 2, Chapters

(12±24), 8th edn. May 1995.

2 McGraw TT, Keon TP. Malignant

hyperthermia and the clean machine.

Canadian Journal of Anaesthesia 1989; 36:

530±2.

A reply

Thank you for allowing us to respond

to this letter. Drs Kang and Hwangcorrectly describe the gas measurementtechnology and limitations of the

M1026A Anaesthetic Gas Module(AGM) in a previous version that atthat time was able to measure any one

of the ®ve anaesthetic agents whenselected manually, but could automati-cally identify only three of them, in this

particular case halothane, iso¯urane anddes¯urane or sevo¯urane. Note that the

reported situation would not haveoccurred with the current version ofAGM, which is able to automaticallyidentify all ®ve agents.

Due to the described ambiguity inthe absorption properties, the devicecannot distinguish between des¯urane

and sevo¯urane. Therefore, the userneeds to con®gure the device to assumeDES (if des¯urane is regularly used at

this institution) or SEV (if sevo¯urane iscommonly used) in AUTO identi®ca-tion mode. If both gases are used in

different cases, there is no alternative toeither selecting the appropriate agent inMANUAL mode or con®guringAUTO to assume the appropriate agent

by default.The phantom vapour detection

results from the combination of the

above effect with a second effect: oneagent can be measured by the device ata given time only. If there is a transi-

tory mix of two agents in the breathingsystem due to switching from oneagent to another, the dominant agent

with the higher concentration is iden-ti®ed and displayed. In the reportedcase, the correct display would havebeen sevo¯urane (still dominant from

the previous case), which was misin-terpreted by the device as des¯uranebecause the user had switched the

device back to AUTO identi®cationmode, but did not set sevo¯urane asthe default agent in AUTO. The

expected display of ISO did in factappear as soon as iso¯urane started tobecome the dominant agent in thebreathing system.

It is important to note that theautomatic agent identi®cation is a safetyfeature in itself because it draws the

user's attention to a discrepancy betweenwhat the anaesthetist decided to deliverto the patient and what is really detected.

In the reported case the wrong agentdisplay has in fact triggered the user totake a deeper look at the problem.

Also, a warning message (AGT mix-ture) is displayed on the monitor as longas more than one agent is detected, anda question mark is displayed next to the

displayed concentration value to makethe user aware of this situation.

The reported problem when using

the 3-agent-ID version of the AGM can

be avoided by complying with thefollowing rules:1 The breathing system should be¯ushed with fresh gas when changing

patients or agents.2 The user needs to con®gure thedevice for being able to detect and

identify des¯urane or sevo¯urane as thethird possible agent: if the hospital isusing sevo¯urane (and no des¯urane),

the AUTO mode should be con®guredto SEV, and if des¯urane is used (and nosevo¯urane), then DES would be the

correct default con®guration.In case both des¯urane and

sevo¯urane are used on the samemachine in different cases, the correct

agent to be measured should beselected manually.

W. Huehn

Phillips Medical Systems

E-mail: [email protected]

Anaesthetic machine safety ±the story continues

I read with interest the recent corre-spondence regarding the anaestheticmachine checklist (Bhargava & Dexter.

Anaesthesia 2001; 56: 1007±8, Shirley &Pogson. Anaesthesia 2001; 56: 1008±9)and would like to raise further points for

discussion. Drs Bhargava and Dexterstate that Ômany machines do not haveparamagnetic oxygen analysers built in

to indicate oxygen failure ¼Õ. I agreethat many machines, especially olderones, do not have paramagnetic oxygen

analysers built-in, but battery drivenfuel cell oxygen analysers can easily beutilised thereby overcoming this prob-lem. Furthermore, the Association of

Anaesthetists of Great Britain and Ire-land (AAGBI) Checklist for AnaestheticApparatus 1997 [1] clearly states during

the introduction that: ÔAs before, theworking party bases this checklist on theobligatory use of an oxygen analyser on

every anaesthetic machine. Thisapproach will ensure that hypoxic mix-tures are not delivered to patients and

also detect mis®lling of oxygen cylin-ders, contamination of liquid oxygenreservoirs and incorrect connectionswithin the machine.

Correspondence Anaesthesia, 2002, 57, pages 183±208......................................................................................................................................................................................................................

192 Ó 2002 Blackwell Science Ltd

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I agree that the presence of a hypoxicguard may have prevented the unnec-essary death of the young child atNewham General Hospital, but herein

lies a further issue. It could be arguedthat it was not the lack of a hypoxicguard or the apparent lack of an oxygen

analyser on the machine that led todisaster, but that it was caused by theÔhuman factorÕ; namely, a piece of

specialised anaesthetic equipment beingused by someone unfamiliar with thesafety features, pre-use checklist or its

proper usage. In simple terms, it was notthe machine but the man behind themachine. Training, I believe, is thecornerstone of good clinical practice

and safety. Therefore, we as anaesthe-tists have a duty of care to help trainnon-anaesthetic personnel in the correct

procedures if they are to use these piecesof anaesthetic equipment in areas suchas Accident and Emergency.

Continuing on a similar theme, onemust welcome any potential advance inanaesthesia that may improve the qual-

ity of care that we can deliver. It wastherefore interesting to read the letterfrom Drs Shirley and Pogson regardingthe possibility of improved safety using

computerised aide-memoires. The useof computer technology in anaesthesiais becoming prevalent but I would like

to introduce two issues. The AAGBIguidelines state clearly that ÔIt is stron-gly recommended that a record of the

check performed should be kept; this isbest done by the use of a speci®clogbook attached to each anaestheticmachineÕ. I have recently completed a

6-month post as a resident in paediatricintensive care at Guy's Hospital, Lon-don. A large number of patients on the

unit either present with upper airwaysobstruction or have the potential todevelop it, for example, post extuba-

tion. The use of an inhalational induc-tion was therefore a commonprocedure. For this purpose we had

an old Boyles machine, which utilisedboth cylinder and pipeline supply, witha fuel cell oxygen analyser attached.The machine was checked every day

and also prior to use, and this wasrecorded by the ticking of boxesagainst each of the criteria laid down

in the AAGBI 1997 checklist. This

acted as not only and aide-memoirebut as a visual record that the checkhad been performed and by whom. Ofcourse this system could lend itself to

being computerised to facilitate theprocess. I believe that not only theperformance of pre-operative checks

but also the recording of these checksis important, especially in this litigiousage. The maxim ÔIf you did not record

it then it did not happenÕ could quiteeasily slip from a lawyers lips.

Finally, I fully welcome the com-

ments from Dr Birks and feel that it isappropriate that the checklist is updatedto incorporate new technology, andthat this be done sooner rather than

later.

S. A. Hellewell

Southampton General Hospital,

Southampton, SO16 6YD, UK

E-mail: [email protected]

Reference1 Checklist for Anaesthetic Apparatus, 2.

London: Association of Anaesthetists

Great Britain and Ireland 1997.

Halothane vs. sevo¯urane inthe dif®cult airway

We read with interest the recent study

(Girgis et al. Anaesthesia 2001; 56:613±15). The authors suggest that sevo-¯urane may be superior during gas

induction of patients with dif®cultairways although they only suggest thatsevo¯urane is the better agent Ôin termsof speed of awakeningÕ. While more

rapid awakening would seem to bedesirable, we believe that this wouldmake airway management more

dif®cult.Following an inhalational induction,

there is a period of airway manipulation

both to examine the airway and toachieve de®nitive airway access (usuallyby intubation). If the depth of anaes-thesia lightens too quickly, then the

patient may develop an acute airwayobstruction due to laryngospasm which,in a patient with an already compro-

mised airway, may prove to be lifethreatening. This study demonstrateswell that the concentration of sevo¯u-

rane may fall from 2 MAC to 0.23MAC in only 3 min. We would arguethat this would not provide ideal con-ditions for managing a dif®cult intuba-

tion.In light of the above, whilst we agree

with the authors that sevo¯urane is

superior in terms of speed of awaken-ing, we believe that halothane remainsthe most appropriate volatile to use

for the Ôdif®cultÕ airway, as changes indepth of anaesthesia are more gradual.

S. J. Mills

E. P. McKiernan

Royal Preston Hospital,

Preston PR2 9HT, UK

E-mail: [email protected]

A reply

Thank you for the opportunity to reply

to Dr Mills and Dr McKiernan's letter,referring to our recent article.

Although it is our opinion that

sevo¯urane is an overall better agentfor induction of anaesthesia in patientswith dif®cult airways, we were careful

not to make such a statement in ourarticle. Instead, we limited ourselves tosuggesting that patients may wake up

more rapidly if the airway obstructscompletely during inhalation inductionof anaesthesia. Our attitude was obvi-ously based on our recognition that

various factors may in¯uence the pref-erence of individual anaesthetists. How-ever, we are happy to continue the

debate of halothane vs. sevo¯urane indif®cult airway management. Wewould therefore like to ask the readers

to consider three possible scenarios,which could occur while dealing withanticipated dif®cult airways.

Scenario 1: Inhalation induction is

complicated by complete airwayobstruction. Our paper suggests thatsevo¯urane may be the better agent in

this situation, as patients would wake upmore rapidly.

Scenario 2: Inhalation induction is

uncomplicated and when adequatedepth of anaesthesia is reached, directlaryngoscopy and tracheal intubation

are carried out in a swift and straight-forward fashion. We would then sug-gest that sevo¯urane is as good as

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halothane as the change in depth ofanaesthesia during the short period ofairway manipulation with either agentwould be insigni®cant.

Scenario 3: Inhalation induction isuncomplicated and when adequatedepth of anaesthesia is reached, attempt-

ed laryngoscopy fails to reveal thelarynx or attempted intubation of avisualised larynx cannot be achieved. If

using sevo¯urane, one would thenre-apply the facemask, maintain anaes-thesia and consider the available

options. These could include wakingthe patient up, using the ®breopticlaryngoscope, performing tracheostomyor even switching to halothane (if it is

anticipated that further attempts atdirect laryngoscopy and intubation docarry a reasonable chance of success). In

the latest event, nothing would havebeen lost and had halothane been usedfrom the start, the options would have

remained the same.Therefore, in scenarios 2 and 3, both

halothane and sevo¯urane are equally

safe, if used appropriately. However,one can never know which patient maypresent as the ®rst scenario. According-ly, we contend that sevo¯urane may

indeed be the best option when startingan inhalation induction.

Y. Girgis

The Royal Orthopaedic Hospital,

Birmingham, UK

E-mail: [email protected]

C.M. Frerk

Northampton General Hospital,

Northampton, UK

Novel use of capnographyduring an awake ®breopticintubation

Normally during a ®breoptic intuba-tion, visual identi®cation of airway

anatomy ensures correct placement ofa tracheal tube. We would like to reporta case in which capnography wasutilised to con®rm correct scope place-

ment during a particularly dif®cultintubation.

A 54-year-old gentleman presented

for debridement and split-skin graftingof 45% truncal burns, sustained approx-

imately 24 h previously when his shirthad caught ®re. Although he had nosymptoms or signs of burns to hisairway, the mechanism of injury gave

a high index of suspicion. In addition,he had a severe ®xed kyphosis second-ary to long standing ankylosing spondy-

litis, with mouth opening of only two®ngerbreadths due to apposition of hischin to his sternum. From previous

anaesthetic records he had been increas-ingly dif®cult to intubate, requiring anawake ®breoptic intubation for his last

anaesthetic 2 years previously.The awake ®breoptic intubation was

performed by two consultants experi-enced in the technique. Standard mon-

itoring was attached, and 2 L.min)1

oxygen administered via a nasal prong.A 1-mg bolus of midazolam was given,

and a remifentanil infusion commencedat 0.1 lg.kg)1.min)1. Having anaesthe-tised the nasopharynx with topical

cocaine and 4% lidocaine, the broncho-scope (Olympus LF-2), loaded with a6.5-mm armoured tracheal tube, was

advanced through the right nostril intothe pharynx. The larynx was dif®cult tovisualise due to its anterior position, andwas also red and oedematous. After

10 min of attempted intubation, thescope was apparently manoeuvredthrough the cords into the trachea.

However, since the mucosa was grosslyoedematous, no tracheal rings could beidenti®ed and a satisfactory view of thecarina could not be obtained.

It was then decided to connect thesample tubing of the capnograph to thesuction port of the bronchoscope

(Fig. 9). When the suction port wasopened, a satisfactory end tidal carbondioxide trace was displayed, con®rming

that the scope was indeed located in thetrachea (Fig. 10). A 6.5-mm armouredtube was railroaded over the scope, and

anaesthesia induced using propofol.Although capnography should always

be used once the tracheal tube has beenpositioned [1], it is rarely necessary prior

to this in an awake patient. Its use hasbeen described as a respiratory ratemonitor during ®breoptic intubation

[2], but this case illustrates that whenextreme anatomical changes are en-countered, all the techniques in an

anaesthetist's armoury may need to becalled upon in order to achieve a secureairway.

D. S. Earl

S. Shinde

K. E. Bullen

J. A. Carter

Frenchay Hospital,

Bristol BS16 1LE, UK

E-mail: [email protected]

References1 Recommendations for Standards of Moni-

toring During Anaesthesia and Recovery,

3rd edn. The Association of Anaesthe-

tists of Great Britain and Ireland

December 2000.

2 Neidhart G, Kovac AK, Bremerich DH,

Kessler P. Remifentanil-propofol for

bronchoscopic fiber optic intubationFigure 9

Figure 10

Correspondence Anaesthesia, 2002, 57, pages 183±208......................................................................................................................................................................................................................

194 Ó 2002 Blackwell Science Ltd

Page 13: Just who do they think we are?

under capnographic control. Anaesthetist

2000; 49: 523±6.

Arterial line insertion

If the trans®xion technique of non-

seldinger arterial cannulation is used,when the metal needle stylet is removed,an epidural loss of resistance syringe with

plunger pulled back is attached to theplastic cannula. The plastic cannula isslowly withdrawn; when in the lumenof the artery, the syringe will slowly ®ll

with blood and the cannula can beadvanced with the knowledge that itremains in the artery. Because the

splinting effect of the metal stylet is lost,we rotate the cannula using the syringe,screwing the cannula into the artery,

which reduces skin and arterial wallresistance to advance and prevents buck-ling of the cannula. For direct non-

trans®xion cannulation, the ¯ashbackchamber on the metal stylet can bechanged for a loss of resistance syringe,giving more time for manoeuvres.

M. Dollman

W. F. S. Sellers

Kettering General Hospital,

Kettering NN16 8UZ, UK

Flush volume for a vascularaccess device

I would like to report a study looking at

the volume of ¯ush required after usinga Port-a-cathÒ II vascular access device.

Several indwelling vascular access de-

vices are available for administration oflong-term parenteral therapy. Whenpresent, such a catheter may also be used

for intravenous induction of generalanaesthesia. Following its use, ¯ushingof the system is crucial to remove residual

drugs. Failure to carry this out adequatelycould be catastrophic should even asmall volume of drug be ¯ushed intra-venously when the line is next used.

This is particularly pertinent to paedi-atric anaesthetic use. The effectivenessof ¯ushing will depend on various

factors including the volume of ¯ush.A commonly used device is the

Port-a-cathÒ II single lumen Polysul-

phone ¤ Titanium Venous Access

System with 1.0 mm internal diameter ¤78 cm length polyurethane catheter(SIMS Deltec, Inc.). The system con-sists of a portal with self-sealing silicone

septum, accessible by percutaneous nee-dle puncture, and a single-lumen cath-eter. Priming volumes, as given by the

manufacturer, are 0.5 ml for the portaland approximately 0.7 ml for the non-shortened catheter. The manufacturers

suggest that, after drug administration,the system be ¯ushed with 5 ml ofnormal saline followed by 5 ml of

heparin solution. This recommendationis not based on speci®c study data.There is a paucity of research intominimum ¯ush volumes, although one

study addressed the issue in giving setextension tubing [1]. It was shown thatrapid ¯ushing, producing non-laminar

¯ow, was more ef®cient at removingresidual drug than slower ¯ow. I pro-ceeded to determine the in vitro mini-

mum safe ¯ush volume required for thePort-a-cathÒ.

An 18G needle was used to access the

device. The line was primed with 0.4%trypan blue solution. A variable ¯ushvolume, between 1 and 10 ml, ofsodium chloride 0.9% was then injected

rapidly using a 10-ml syringe. Follow-ing the ¯ush, in order to determine theamount of trypan blue remaining in the

vascular access system, 10 ml of sodiumchloride 09% was injected slowly usinga 10-ml syringe, and the ¯uid emerging

from the catheter tip collected. Theconcentration of dye in the collected¯uid was determined by measuring itsoptical density (at 240 nm wavelength)

using spectrophotometry (Pye Unicam,

SP6-550 UV ¤ VIS). The Port-a-cathÒwas thoroughly purged before repeatingthe process with a different ¯ush vol-ume. The data collected are shown in

Fig. 11. The curve levels out at a ¯ushvolume of 5 ml implying that greater¯ush volumes were no more effective.

This is the minimum safe ¯ush volumein vitro when injected rapidly. Otherfactors are relevant in vivo including the

hydrostatic pressure at the line tip, i.e.the central venous pressure.

In conclusion, the manufacturer's

instruction for a 5-ml ¯ush (followedby 5 ml of heparin solution) is adequatewhen injected rapidly. This study willbe reassuring to users of this Port-a-

cathÒ and could easily be repeated forother vascular access devices.

A. Brennan

The Calderdale Royal Hospital,

Halifax HX3 0PW, UK

Reference1 Hutton P, Thornberry EA. Factors

affecting delivery of drug through

extension tubing. British Journal of

Anaesthesia 1986; 58: 1141±8.

Experience of complications ofpercutaneous dilatationaltracheostomy

Percutaneous dilatational tracheostomy(PDT) is performed with ever increas-

ing frequency on intensive care units inthe UK. As well as evidence of areduction in incidence of long-termcomplications from this method com-

Figure 11 Optical density of collected ¯uid with variable ¯ush volume.

Anaesthesia, 2002, 57, pages 183±208 Correspondence......................................................................................................................................................................................................................

Ó 2002 Blackwell Science Ltd 195

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pared to open surgical tracheostomy[1±3], it is time- and cost-effective,and convenient as a procedure that canbe done outside of theatre without the

need of either a surgeon or theatrespace. Furthermore, this negates thepotential hazards of transferring criti-

cally ill patients away from the inten-sive care unit. The development ofuser-friendly apparatus for PDT has

further increased its popularity andmany consider it a safe technique [4].However, a concerning aspect of PDT

is the potential for severe acute com-plications. Whilst those in the postop-erative period may be lower, evidencesuggests a higher incidence of peri-

operative complications, includingdeath, with PDT than with surgicaltechniques [3].

Acute severe haemorrhage, loss ofairway including tracheostomy mis-placement, oesophageal rupture, trac-

heal dissection, pneumothorax andhaemothorax have all been described.A discussion with colleagues in the

anaesthetic coffee room usually revealsthat many of those who have performedPDT can recount tales of horror of oneor more such events. Fortunately, most

patients seem to survive their Ônear-missesÕ and suffer no further morbidity,but a few do not. Unless the acute

events are recorded as a critical incidentor as part of an ongoing audit, it ispossible that under reporting of acute

complications occurs as patient follow-up focuses on long-term outcomes.

To examine the experience of acutecomplications of practitioners who per-

form PDT, 60 anonymous surveys weredistributed to consultant and traineeanaesthetists of a local teaching hospital

department. Questions were askedregarding the grade of anaesthetist,how many PDTs each individual had

performed and their experience of acutecomplications, including haemorrhage,pneumothorax, haemothorax, oesopha-

geal rupture, and tracheal dissection.Free comments were invited for othercomplications not speci®ed by the sur-vey. They were also asked which type

of PDT equipment they most com-monly used and whether they routinelyused a bronchoscope to assist tracheos-

tomy placement.

In total, 47 questionnaires werereturned, giving a response rate of78%. Of the respondents, 18 wereconsultant anaesthetists (38%), 22 were

SpRs (47%) and 7 were SHOs (15%).The number of PDT performed byeach individual is shown in Table 4. Of

the 42 respondents that had performedPDT, 23 (55%) reported experience ofacute severe complications. The most

common of these reported was that ofhaemorrhage, with 10 (24%) reportingit as a sole complication, and a further 9

(21%) reporting it alongside others.Eight (19%) of the respondents hadvoluntarily described either a loss ofairway or misplacement of the trach-

eostomy during the procedure. Three(7%) of the respondents reported caus-ing pneumothoraces to patients under-

going PDT and two (5%) had seensurgical emphysema as a direct compli-cation. One individual reported having

caused a haemothorax during PDT andnone of the respondents had experi-enced oesophageal rupture or tracheal

dissection. Of those anaesthetists whohad performed PDT, the most popularkit used was the Ciaglia TM dilator kit,with 16 (38%) respondents using it; 6

(14%) used the Blue Rhino TM, whilst 8(19%) reported using a combination ofboth. Ten (24%) used Portex TM and

the remaining 5% used other kitsincluding Rusch TM and MallinkrodtTM. Of those who had performed PDT,

37 (88%) reported using a bronchoscoperoutinely in assisting placement.

This survey con®rms the popularityof PDT, with 89% of respondents

having performed it at least once. Italso demonstrates that acute and oftensevere, potentially life-threatening com-

plications are not uncommon duringthis procedure, with over 50% ofrespondents experiencing one or more.

Several modi®cations in practice toPDT have been suggested to reduce theincidence of such complications. Onemodi®cation that has been widely

adopted is the use of a ®breopticbronchoscope, which has been suggestedfor use in assisting correct placement

and to reduce the risk of airway loss [5].The majority of respondents in thissurvey routinely used a bronchoscope

to assist placement of PDT and this isarguably recognised as good practice.However, of the eight who reported

loss of airway or misplacement of thetracheostomy, six reported routinelyusing a bronchoscope. Also, there islittle evidence to suggest that bronchos-

copy reduces the incidence of haemor-rhagic events from a PDT. Some studieshave suggested that the risk of haemor-

rhage could be minimised by the use ofultrasound techniques to identify theposition of major vessels in the neck

before performing the PDT [6, 7].Operator experience may also play apart in the incidence of acute compli-

cations. One study demonstrated asigni®cant learning curve for perform-ing PDT, particularly in the ®rst 20patients, with most complications

occurring during acquisition of earlyexperience in the technique [8]. In thissurvey, 27 people fell within this early

learning curve episode. Over half(55%) of these, however, reported hav-ing never experienced a complication.

Paradoxically, of the 15 who had per-formed greater than 20 PDTs, two-thirds had. This survey is too small todeduce any statistical signi®cance from

such ®ndings, and it may well be thatthose in the ÔexperiencedÕ group hadseen their complications within their

®rst 20, or perhaps it justi®es the oldadage Ôif you havenÕt seen a complica-tion, you haven't done enough'.

Another important issue of PDT thatmay enhance safety is appropriatepatient selection and surgical referral of

patients with potentially dif®cult orunusual anatomy. Other suggestionsinclude making an adequate incision toenhance identi®cation of the tracheal

rings [5] and the use of capnography tocon®rm correct placement [5, 9].

Thus, whilst the increasingly popular

PDT has undoubtedly proven its worth

Table 4

No. ofPDT performed

No. ofanaesthetists

0 51±20 27> 20 15

Correspondence Anaesthesia, 2002, 57, pages 183±208......................................................................................................................................................................................................................

196 Ó 2002 Blackwell Science Ltd

Page 15: Just who do they think we are?

on the intensive care unit, it wouldseem wise to heed the tales of the manywho seem to have experienced near-disasters and to continue to regard it as a

signi®cantly invasive procedure that isnot without complications, the safety ofwhich can be enhanced by adopting

sensible precautions and appropriatetechnique modi®cations.

H. Wise

Poole Hospital Poole,

BH15 2JB, UK

References1 Freeman BD, Isabella K, Lin N,

Buchman TG. A meta-analysis of pro-

spective trials comparing percutaneous

and surgical tracheostomy in

critically ill patients. Chest 2000; 118:

1412±18.

2 Cheng E, Fee WE Jr. Dilatational vs

Standard tracheostomy: a meta-analysis.

Annals of Otology, Rhinology and

Laryngology 2000; 109: 803±7.

3 Dulguerov P, Gysin C, Perneger TV,

Chevrolet JC. Surgical or Percutaneous

Tracheostomy: a meta-analysis.

Critical Care Medicine 1999; 27:

1617±25.

4 Cooper RM. Use and safety of percu-

taneous tracheostomies in intensive

care-report of a postal survey of UK

practice. Anaesthesia 1998; 53: 1209±27.

5 Marx WH, Ciaglia P, Graniero KD.

Some important details in the technique

of percutaneous dilatational tracheos-

tomy via the modified Seldinger tech-

nique. Chest 1996; 110: 762±6.

6 Hatfield A, Bodenham A. Portable

ultrasonic scanning of the anterior neck

before percutaneous dilatational trach-

eostomy. Anaesthesia 1999; 54: 660±3.

7 Muhammad JK, Major E, Wood A,

Patton DW. Percutaneous dilatational

trachesotomy: haemorrhagic compli-

cations and the vascular anatomy of

the anterior neck. A review based on

497 cases. International Journal of Oral

and Maxillofacial Surgery 2000; 29:

217±22.

8 Massick DD, Powell DM, Price PD,

Chang SL, Squires G, Forrest LA,

Young DC. Qualification of the

learning curve for percutaneous dilata-

tional tracheostomy. Laryngoscope 2000;

110: 222±8.

9 Coleman NA, Power BM, van

Heerden PV. The use of end-tidal

carbon dioxide monitoring to confirm

intratracheal cannula placement prior to

percutaneous dilatational tracheostomy.

Anaesthesia and Intensive Care 2000; 28:

191±2.

Single-lung ventilation via adouble lumen tube in a patientwith a tracheostomy

A recent letter in this journal described

the use of a ®breoptically directedÔsteerableÕ endobronchial blocker inassociation with a tracheostomy tube

to provide single-lung ventilation in apatient with a permanent tracheostomy(Matthews et al. Anaesthesia 2001; 56:492±3). Other techniques available

include double lumen tracheostomytubes and endobronchial intubationwith a single lumen tube. We would

like to describe the use of a conven-tional double lumen tube in this situa-tion.

A 44-year-old man presented forleft pneumonectomy for an upper lobesquamous cell carcinoma, just

2 months following a total laryngec-tomy for a squamous cell laryngealcarcinoma. The patient was anaesthe-tised with midazolam 1 mg, morphine

5 mg, thiopental 325 mg and vecuro-nium 10 mg, and was easily ventilatedusing a paediatric face mask positioned

over the tracheostomy. A right-sided37G Mallinckrodt double lumen tubewas passed through the stoma and into

his trachea. The correct position ofthe tube was checked clinically andcon®rmed with a ®breoptic broncho-scope. Once the patient was in posi-

tion for a left thoracotomy, the tubelay easily on the side of his face asshown in Fig. 12.

We feel there are a number ofadvantages to this technique. Firstly,double lumen tubes are usually more

readily available than double lumentracheostomy tubes or bronchialblockers. Second, anaesthetists have

more experience positioning doublelumen tubes than bronchial blockers,and ®nally, once the patient is posi-tioned and prepared for surgery, the

extra length and ¯exibility of thedouble lumen tube allows easier accessto the airway, facilitating such ma-

noeuvres as suctioning and checkingtube position intra-operatively with a®breoptic bronchoscope. We would

recommend this technique as a simplesolution to what can be an awkwardproblem.Figure 12 Double lumen tracheal tube in situ. The patient is in the right lateral position.

Anaesthesia, 2002, 57, pages 183±208 Correspondence......................................................................................................................................................................................................................

Ó 2002 Blackwell Science Ltd 197

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M. C. Renton

I. D. Conacher

Freeman Hospital,

Newcastle upon Tyne NE4 6BE, UK

E-mail: [email protected]

Acid-base disorders in thecritically ill

The recent paper (Story et al. Anaesthe-sia 2001; 56: 530±3] provides a wel-come demonstration of the utility of the

Stewart approach to the analysis of acid-base disorders in critically ill patients.The authors are to be commended ontheir clear illustration of the potential of

this methodology to offer mechanisticinsights not readily attained with themore traditional Henderson-Hasselbach

approach. The demonstration thatdecreases in plasma albumin, a common®nding in critically ill patients, may

have contributed to the alkalosis seen intheir patients is of particular interest.

The authors suggest that an acidifying

effect of increasing plasma albuminconcentration may play a role in theapparent adverse effect of albumintherapy reported in a recent meta-

analysis [1]. This contention reveals acommon and important misconceptionregarding acidosis and outcome from

illness. While acidosis is clearly associatedwith poor outcome, this does not implycausation. Acidosis, particularly lactic

acidosis, may indicate tissue dysoxia;however, acidosis per se is not necessar-ily harmful [2]. In fact, there is abundant

evidence in the literature that acidaemiamay exert protective effects in thecontext of acute organ injury. Acidosis,metabolic and ¤ or hypercapnic, is pro-

tective in a variety of animal models ofneurologic [3], cardiac [4], and pulmo-nary injury [5±7]. The mechanisms

underlying the protective effects ofacidosis are becoming increasingly clear,and include attenuation of key compo-

nents of the in¯ammatory process, andreduction of cellular respiration andoxygen consumption [2]. A recentnovel hypothesis [8], pointing out that

acidosis protects against ongoing tissueproduction of further organic acids (by anegative feedback loop), provides a

mechanism for cellular metabolic shut-

down at times of nutrient shortage, e.g.ischaemia.

This distinction between cause andassociation is of particular importance in

regard to the practice of buffering.Buffering of acidosis remains a com-mon, if controversial practice [9, 10].

The physiologic rationale for this prac-tice is based on the concept that acidosisis directly harmful and therefore must

be treated. However, there exists little ifany data to support the practice ofbuffering acidosis. In fact, there is

evidence from laboratory models oflung injury that buffering may abolishthe protective effects of acidosis [7].

In summary, in the light of current

evidence, it may be timely to re-eval-uate our traditional concepts regardingacidosis.

J. G. Laffey

St. Vincent's University Hospital,

Dublin, Ireland

References1 Cochrane Injuries Group Albumin

Reviewers. Human albumin adminis-

tration in critically ill patients: system-

atic review of randomised controlled

trials. British Medical Journal 1998; 317:

235±4.

2 Laffey JG, Kavanagh BP. Carbon

dioxide and the critically ill -too little of

a good thing? Lancet 1999; 354: 1283±6.

3 Vannucci RC, Towfighi J, Heitjan DF,

Brucklacher RM. Carbon dioxide

protects the perinatal brain from hyp-

oxic-ischemic damage: an experimental

study in the immature rat. Pediatrics

1995; 95: 868±74.

4 Kitakaze M, Takashima S, Funaya H,

et al. Temporary acidosis during

reperfusion limits myocardial infarct

size in dogs. American Journal of

Physiology 1997; 272: H2071±8.

5 Moore TM, Khimenko PL, Taylor AE.

Restoration of normal pH triggers

ischemia-reperfusion injury by Na ¤ Hexchange activation. American Journal of

Physiology 1995; 269: H1501±5.

6 Shibata K, Cregg N, Engelberts D,

Takeuchi A, Fedorko L, Kavanagh BP.

Hypercapnic acidosis may attenuate

acute lung injury by inhibition of

endogenous xanthine oxidase. American

Journal of Respiratory Critical Care

Medicine 1998; 158: 1578±84.

7 Laffey JG, Engelberts D, Kavanagh BP.

Buffering hypercapnic acidosis worsens

acute lung injury. American Journal of

Respiratory Critical Care Medicine 2000;

161: 141±6.

8 Hood VL, Tannen RL. Protection of

acid-base balance by pH regulation of

acid production. New England Journal of

Medicine 1998; 339: 819±26.

9 Vukmir RB, Bircher N, Safar P. Sodi-

um bicarbonate in cardiac arrest: a

reappraisal. American Journal of Emergency

Medicine 1996; 14: 192±206.

10 Levy MM. An evidence-based evalua-

tion of the use of sodium bicarbonate

during cardiopulmonary resuscitation.

Critical Care Clinics 1998; 14: 457±83.

A reply

We appreciate Dr Laffey's interest in

our paper. Dr Laffey raises the possibil-ity that acidosis may be protective. Wesaid in our paper that the acidosis

secondary to albumin therapy mightbe a cause of adverse outcome. Weaccept, if Dr Laffey were correct, that

this statement would be wrong. Likethe Stewart approach to acid-baseDr Laffey's suggestion is contrary tomuch of the mainstream thinking but

has considerable supporting research.Further, like the Stewart approach, thechallenge for the future is to determine

the truth through clinical studies.

D. Story

S. Poustie

R. Bellomo

Austin and Repatriation Medical

Centre,Victoria 3084, Australia

E-mail: [email protected]

Inadvertent catheterisation of apartial anomalous pulmonaryvenous channel during centralvenous cannulation

A 71-year-old Chinese woman with ahistory of ischaemic heart disease, atrial

®brillation and non-insulin-dependentdiabetes mellitus was admitted withnecrotizing fasciitis of her right leg.On admission, she was septic with

signs of diabetic ketoacidosis. A centralvenous catheter was inserted via the

Correspondence Anaesthesia, 2002, 57, pages 183±208......................................................................................................................................................................................................................

198 Ó 2002 Blackwell Science Ltd

Page 17: Just who do they think we are?

right subclavian vein to aid ¯uid resus-citation. A chest radiograph showedthat the catheter tip was in the ipsilateralinternal jugular vein, and was therefore

removed.After induction of general anaesthe-

sia, another central venous catheter was

inserted via the left internal jugular (LIJ)vein. As the pressure waveform andreadings were consistent with that of a

central vein, and there was good blood¯ow on aspiration of the ports, thiscatheter was used for monitoring andinfusion purposes during surgery.

Following surgery, she was transferredto the surgical intensive care unit wherethe admission chest radiograph revealed

that the central venous catheter wasprojected along the left lateral border ofthe heart. As the location of this catheter

was unclear, another catheter wasinserted via the right internal jugular(RIJ) vein with no complications.

On closer inspection, the pressurewaveforms from the two catheters weremorphologically different with the pres-sure recorded via the LIJ catheter

5 mmHg higher than that from theRIJ catheter. Blood aspirated from theLIJ catheter showed a PaO2 of

212 mmHg, whilst that from the radialarterial cannula was 196 mmHg. Bloodaspirated from the RIJ catheter had a

PaO2 of 52 mmHg. These blood sam-ples were taken simultaneously whilethe patient's lungs were being ventilatedwith an inspired oxygen concentration

of 40%.

Doppler ultrasound studies con®rmedthat the LIJ catheter was lying within avein in the neck. Venograms were thenperformed with the injection of contrast

medium through both catheters. The tipof the LIJ catheter was located within avessel inferior to the con¯uence of the

left internal jugular and subclavian veins(Fig. 13). As blood was ¯owing towardsthe catheter from this anomalous chan-

nel, manual injection of the contrastmedium could not reveal the origin ofthis anomaly. Contrast medium injectedthrough the RIJ catheter was seen to

enter the right side of the heart and thepulmonary circulation, followed rapidlyby the anomalous channel. The LIJ

catheter was removed, though onanother occasion it was used for centralvenous access, when the catheter tip

went into the brachiocephalic vein.Anomalous pulmonary venous con-

nections occur when at least one pul-

monary vein is connected to the rightatrium either directly or indirectly via avenous tributary. A partial anomalouspulmonary venous connection (PAP-

VC) occurs when one or more, but notall, the pulmonary veins connect to theright atrium. These may be found in

association with atrial septal defects.There are a number of potential vari-ants, but the variants with anomalous

right pulmonary veins are said to betwice as common as those involving theleft side.

PAPVCs are usually asymptomatic,

remain undiagnosed during life and are

incidental post mortem ®ndings [1]. Theincidence ranges from 0.4 to 0.7% indifferent series. Although they are asso-ciated with cardiopulmonary malforma-

tions, there are no known risk factors forthe development of this abnormality.The haemodynamic consequence is a

left-to-right shunt and the consequentvolume overload to the right heart withdilatation of the right atrium, right

ventricle and pulmonary artery. The leftheart chambers tend to be unaffectedand the cardiac output remains normal.

Pulmonary hypertension is not a recog-nised complication. Surgical correctionis not required in the absence of othercardio-pulmonary malformations.

The slightly different pressure wave-form morphology that we observed is incontrast to previous reports [2, 3] of

PAPVC catheterisation, in which anearly sign was a markedly abnormalwaveform with pulsatile ¯ow of bright

red blood. The explanation for thesewas wedging of the catheter in thepulmonary vein, resulting in the trans-

mission of the pulmonary arterial pres-sure waveform. Such waveformanomalies, if recognised early, mayindicate misplacement of the central

venous catheter.This case illustrates the value of check

chest radiographs in the correct identi-

®cation of central venous catheterposition. Congenital vascular abnormal-ities are rarely diagnosed in this way

unless catheterisation of either a leftsuperior vena cava or a partial anoma-lous pulmonary venous channel occurs.If the left superior vena cava is cathe-

terised, the catheter will be seen to travelin a left paramediastinal path initially,then cross the mediastinum deeper

within the thorax. In such a situation,the pressure waveforms would conformto that of a normal central vein.

Digital subtraction angiography hasbeen used to de®ne PAPVCs withoutsubjecting patients to the risks of con-

ventional angiography [4]. Non-radio-logical methods of diagnosing thepresence of partial anomalous pulmo-nary venous channels include transth-

oracic [5] or trans-oesophageal [6] echocardiography. Transthoracic echocardi-ography done on this patient a few years

previously had merely revealed bi-atrial

Brachiocephalic vein

RIJ central venous catheter

Superior vena cava

Anomalous venous channel

Tip of LIJ catheter

Figure 13 Digital subtraction venography with the injection of contrast mediumthrough the LIJ catheter showing the anomalous venous connection at the point wherethe internal jugular vein continues into the left brachiocephalic vein.

Anaesthesia, 2002, 57, pages 183±208 Correspondence......................................................................................................................................................................................................................

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enlargement and did not suggest thepresence of an atrial septal defect. Wefelt it was unnecessary to subject her totrans-oesophageal echocardiography

when there was little doubt about thediagnosis after the radiological studies.

C. J. C. Cheng

B. L. Lim

B. S. Tan

Singapore General Hospital,

Singapore 169608

E-mail: [email protected]

References1 Ward KE, Mullins CE. Anomalous

pulmonary venous connections; pul-

monary venous stenosis; atresia of the

commonpulmonaryvein. In:Garson A Jr,

Bricker JT, McNamara DG, eds. The

Science and Practice of Pediatric Cardiology.

Lea & Febiger Philadelphia ¤ London

1990, 1145±72.

2 Orme R, Harper L, Olliff JFC. Case of

the month. In what's my line? British

Journal of Radiology 1998; 71: 457±8.

3 Wylam ME, Schmidt GA. Serendipi-

tous discovery during jugular cathe-

terisation. Partial anomalous pulmonary

venous connection. Chest 1996; 98:

493±5.

4 Sider L, Fisher MR, Minzer RA. The

evaluation of partial anomalous pul-

monary venous return with the use of

digital subtraction angiography. Chest

1984; 86: 97±9.

5 Higgs AG, Paris S, Potter F. Discovery

of left-sided superior vena cava during

central venous catheterization. British

Journal of Anaesthesia 1998; 81: 260±1.

6 Garduno C, Chew S, Forbess J,

Smith PK, Grocott HP. Persistent left

superior vena cava and partial anoma-

lous pulmonary venous connection:

incidental diagnosis by transesophageal

echocardiography during coronary

artery bypass surgery. Journal of the

American Society of Echocardiography

1999; 12: 682±5.

Correct nomenclature forstereo isomers

Recently, there has been a move to

produce enantiopure agents, therebyreducing unwanted or potentially toxic

effects associated with certain anaesthet-ic agents. It therefore seemed appropri-ate for a review on levobupivacaine(McLeod & Burke. Anaesthesia 2001;

56: 331±41) to appear with a shortreÂsume of optical isomerism. However,I was disappointed on two counts, one

to ®nd the information given concern-ing the naming of chiral molecules to beinaccurate, and secondly with the inad-

equate description of symmetry. Whenconsidering stereoisomerism in generaland optical stereoisomerism in particu-

lar, there is a need for accuracy, which Ifelt was lacking in the general intro-duction to this review. As an example,there was no attempt to make clear the

distinction between geometric stereoi-somers and optical stereoisomers ± apoint often missed by trainees preparing

for examinations.The S and R con®gurations are, as

correctly pointed out, based on the

absolute con®guration of the four asym-metrical groups around the chiral cen-tre, usually a carbon atom but often a

quaternary nitrogen. Unfortunately, thethree-dimensional nature of this ar-rangement does not lend itself to beingrepresented unambiguously on a ¯at

plane such as a piece of paper. Thus, it isinaccurate to suggest Ôof the four atomssurrounding the stereogenic centre, the

order of size from highest to lowest isnotedÕ. A more accurate description is:®rstly, identify the atom with the lowest

atomic number, then imagine you arelooking through the base of the tetra-hedron formed by the four atomstoward the atom previously identi®ed.

The three remaining atoms now lie in asingle plane and if the order of theiratomic number count, starting with the

highest and moving round to the low-est, follows a clockwise sequence then itis the R form, if anticlockwise the S

form. Thus, the entries made in Table 1are actually wrong since one alwaysstarts with the highest atomic number

and moves around to the lowest, but ifyou do start with the lowest, thenmoving from lowest to highest anti-clockwise gives the R form and clock-

wise the S form. Those who areinterested should refer to The PenguinDictionary of Chemistry [1], starting with

the entry for Ôoptical activityÕ. For an

explanation of what to do when, forexample, two or more of the atomsattached to the chiral centre are carbonatoms, but with different substitutions,

look under Ôsequence ruleÕ.I also found the section ÔSymmetryÕ to

be unnecessarily brief. The description

of symmetry given is for re¯ectionalsymmetry only. There are other forms ofsymmetry, namely translational (of im-

portance in tessellations) and rotationalsymmetry. This latter is of importancewhen considering complex molecules

like atracurium that have several chiralcentres and are rotationally symmetricalas this reduces the total number ofpossible three dimensional spatial con-

formations (from 16 to 10 in the case ofatracurium). I do understand that articlelength is limited, but clarity must not be

sacri®ced at the expense of accuracy.

S. A. Hill

Southampton General Hospital,

Southampton SO16 6YD, UK

Reference1 Sharp DWA, eds. The Penguin Dictio-

nary of Chemistry 1990, 5th edn. 287,

356.

Hypo-osmolar Hartmann's

The recent paper (Gray et al. Anaesthesia2001; 56: 461±5) con®rms the associa-tion between bladder pressure during

surgery for trans-urethral prostatectomyand absorption of irrigating ¯uid. Indescribing movement of ¯uid betweenbody compartments during this proce-

dure they state explicitly that theyassume iso-osmolarity. However, theiranaesthetic technique militates against

this because they administer intravenousRinger's Lactate (Hartmann's solution).This is a hypo-osmolar ¯uid (between

273 and 278 mosmol.l±l, depending onformulation) compared with plasma(between 285 and 290 in mosmol.l±l).Its use therefore interferes with their

assumption that infusion of this ¯uid canexacerbate peri-operative osmotic com-plications especially hyponatraemia [1].

There are other problems with usingthis ¯uid. It is incompatible with trans-fused blood (the calcium binding the

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200 Ó 2002 Blackwell Science Ltd

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citrate anticoagulant of blood) and thevasopressor metaraminol. This drugmay become more popular becausemethoxamine is to be withdrawn.

Finally, peri-operative infusion ofHartmann's solution can worsen gly-caemic control of diabetics, a relatively

common group of patients presentingfor prostatectomy [2].

Whilst our comments do not detract

from the author's results, we write tomention that other types of ¯uid ther-apy may be more reasonable.

D. R. Ball

V. Perkins

Dumfries and Galloway Royal

In®rmary,

Dumfries DG1 4AP, UK

References1 Gill G, Leese G. Hyponatraemia:

biochemical and clinical perspectives.

Post Graduate Medical Journal 1998; 74:

516±23.

2 Thomas DJB, Alberti KG. Hypergly-

caemic effects of Hartmann's solution

during patients with maturity onset

diabetes. British Journal of Surgery 1978;

50: 185.

Effective labelling is dif®cult,but safety really does matter

The recent letter discussing the Pog-gendorf effect (Nott. Anaesthesia 2001;

56: 917) is helpful in understandingsome of the complex psychologicalaspects of labelling and safety. Hissuggestion that a second person must

also read the label before the adminis-tration of any drug is certainly of value,but raises a number of issues. The ®rst

concerns resource ± a survey of NewZealand anaesthetists found that in only1.5% of circumstances was a second

person routinely available throughoutthe anaesthetic to check drugs beforetheir administration [1]. The second,more important issue, however, relates

to human fallibility. We have received anumber of routine audit reports docu-menting errors made by nursing staff

who have used a two-person check, butstill got it wrong. Part of the problemseems to be the suggestibility of human

beings. If the second person is shown alabel and asked if it is indeed drug X,then there is a chance that he or she willread the label as drug X, even if it is in

fact a similarly named but differentdrug.

We have developed a new system

designed to reduce the propensity forerror during drug administration inanaesthesia [2]. One feature of this

system is the use of large legible labelsthat include bar codes. When a syringewith such a label is scanned by the

barcode reader just before administra-tion, a computer speaks the name of thedrug as a ®nal check of the syringe'scontents. The computer is of course not

open to suggestion and our system hasalready demonstrated its ability to facil-itate anaesthetists' efforts to avoid drug

error. In this way, we have embodiedthe principle of the two-person check,in a manner that utilises a less expensive

resource than a trained health profes-sional, and that capitalises on thestrength of machines in an area in

which humans are prone to error. Theapproach also makes possible the inclu-sion of various alarms for expired drugsand allergy alerts.

No safety system can be expected toeliminate errors and accidents entirely[2, 3]. We therefore agree with

Dr Nott's statement that colour codingby class of drug will not eliminate erroron its own. Neither will the use of the

bar-coded Ôtwo-person checkÕ describedabove. However, we believe that eachwould be a signi®cant improvement onthe status quo, and both should be

incorporated into a wide-rangingapproach to error reduction, whichincludes (so far as possible) all aspects

of the drug administration environmentin theatre and indeed beyond [2, 4, 5].

The use of colour-coded (and bar-

coded) user-applied syringe labels doesnothing to address the problem ofampoule labelling. We have previously

suggested that manufacturers shouldsupply injectable drugs in appropriatelylabelled pre®lled syringes to remove oneerror-prone step from the process of

drug administration [4]. In reality, thiswill be a long time coming, and thecurrent state of labelling on most

ampoules can only be described as

appalling. Figure 14 shows twoampoules from a drug trolley at ourhospital, which were recently involvedin a substitution near miss. These am-

poules are compliant with the currentNHS speci®cation for ampoule labelling[6]. Yet, despite the fact that the ®gure

shows the drug brand names facingforward (in the largest text on theampoule), the ampoules remain very

dif®cult to read and distinguish fromone another. The black writing on clearglass is hard to read because the writing

on the other side of the ampoule showsthrough and obscures critical informa-tion. The NHS speci®cation suggests theuse of a yellow background for the

lettering on ampoules to increase legi-bility ± but obviously it is simpler andallowable for manufacturers not to

bother. The bands at the base of theseampoules may look like an identi®ca-tion aid such as the rings sometimes

used to indicate the length of action of adrug [7], but they are in fact specialisedbarcodes (without expiry dates) used by

the manufacturer (personal communi-cation, Abbott Laboratories).

We use custom-made pre®lledsyringes where practical in our new

system [2, 4]. In addition we havedesigned a Ô¯agÕ or supplementary labelattached to the ampoule by a licensed

Figure 14

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Ó 2002 Blackwell Science Ltd 201

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pharmaceutical manufacturer with aloop of clear plastic [2]. The ¯ag labeladds the drug name, drug class, its class-speci®c colour cue and a barcode, all in

a highly legible manner, withoutobscuring any of the ampoule's originaldetails (Fig. 15). When the contents of

the ampoule are drawn up, the self-adhesive ¯ag label can be removed andattached to the syringe as part of the

drawing-up process.Consistent colour standards for user-

applied syringe labels in anaesthesia

already exist in Australia, New Zealand,Canada and the United States (discussedin [2]). In addition, ampoule standardsalso exist in Canada and the US, which

allow the use of a colour-coded border,consistent with the aforementionedsyringe label standards, around the Ôcriti-

cal information panelÕ ± thus permittingthe use of consistent ampoule andsyringe label colour cues [8, 9]. Amp-

oule colour coding by class of drug wassuggested 19 years ago, but remainsundeveloped [7]. While it may be con-

venient from an administrative, bureau-cratic or manufacturing perspective tohave different standards for ampoulesand syringes, this makes no sense in

terms of the ergonomics and safety of aclinician administering a drug to a

patient. There is no doubt that gettingthe detail of effective labelling standardsright is dif®cult, but if safety really doesmatter [10], then these dif®culties must

be overcome. Resolution of theseproblems is long overdue.

C. S. Webster

D. J. Mathew

A. F. Merry

Green Lane Hospital,

Auckland, New Zealand

E-mail: [email protected]

References1 Merry AF, Peck DJ. Anaesthetists,

errors in drug administration and the

law. New Zealand Medical Journal 1995;

108: 185±7.

2 Merry AF, Webster CS, Mathew DJ.

A new, safety-oriented, integrated drug

administration and automated anesthe-

sia record system. Anesthesia and

Analgesia 2001; 93: 385±90.

3 Webster CS, Merry AF, Larsson L,

McGrath KA, Weller J. The frequency

and nature of drug administration error

during anaesthesia. Anaesthesia and

Intensive Care 2001; 29: 494±500.

4 Webster CS, Merry AF, Ducat CM.

Safety, cost and predrawn emergency

drugs. Anaesthesia 2001; 56: 818±20.

5 Webster CS, Anderson D, Murtagh S.

Safety and peri-operative medical care.

Anaesthesia 2001; 56: 496±7.

6 Anonymous. Ampoule Labelling ±

NHS Specification 1994 Revision.

National Pharmaceutical Supply Group, 18

March.

7 Smellie GD, Lees NW, Smith EM.

Drug recognition by nurses and

anaesthetists. Anaesthesia 1982; 37:

206±8.

8 Anonymous. Labelling of Drug

Ampoules, Vials, and Prefilled Syringes

(Z264.2±99). Etobicoke: Canadian.

Standards Association 1999.

9 Anonymous. Standard Specification

for Labels for Small-Volume

(100 Ml or Less) Parenteral Drug

Containers (D4267±95). Philadelphia:

American. Society for Testing and Materials

1995.

10 Birks RJS. Safety matters. Anaesthesia

2001; 56: 823±4.

Persistent cough followingtarget-controlled infusion (TCI)with propofol

I was interested to read the description

of a persistent cough during sedationwith propofol given by TCI (Aly.Anaesthesia 2001; 56: 1016). I have seen

similar coughing in patients anaesthe-tised for lower limb or gynaecologicalsurgery with a combination of centralneural block and propofol sedation

given by TCI. Patients were in thesupine or lateral position and receivedsupplementary oxygen via a simple

variable performance mask. In myexperience, the coughing oftenresponds to raising the target propofol

concentration to hypnotic levels, inwhich case a Guedel airway may berequired. However, on occasion I too

have resorted to waking the patient up.Of 28 cases anaesthetised in this way,about 15% have coughed in the mannerdescribed by Dr Aly. Neither regurgi-

tation nor aspiration occurred in anypatient.

C. J. D. Maile

Ronkswood Hospital,

Worcester WR51HN, UK

E-mail: [email protected] 15

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202 Ó 2002 Blackwell Science Ltd

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Use of herbal medicines inambulatory surgical patients

We conducted a study to examine the

frequency and pattern of herbal med-icine usage in patients admitted for daycare surgery. As they waited in the

holding area of the operating depart-ment, 387 consecutive patients attend-ing the hospital for day case surgery

were asked to complete a question-naire. No patient refused to participate.All unpremedicated, ASA physical sta-

tus I and II patients were included.The questionnaire included questionsabout use of herbal medicines in thepre-operative period, source of infor-

mation ¤ referral about herbal prepara-tions, knowledge of side-effects andcoincident administration of prescrip-

tion medications. We also askedwhether the patient's general practitio-ner or surgical team had been informed

that the patient was taking a herbalmedicine.

There were 387 completed question-

naires from 186 males and 201 females.The mean age of subjects was 39 years(range 13±82 years). Forty-sevenpatients (12.1%) were currently taking

a herbal remedy. The mean age ofpositive respondents was 38 years(range 18±70 years). Sixty-eight percent

of those taking herbs were female. Ofthe 47 patients taking a herbal prepara-tion, 27.7% were taking more than one

preparation, and 34% were taking aprescribed medication in addition to theherbal product.

There was a wide variety of prep-

arations in use, with garlic, ginseng,echinacea and arnica being the mostfrequently reported. Twenty-seven

percent of those taking a herbal prep-aration were doing so on the advice ofan alternative practitioner. Thirty-two

percent had learned of the herbalmedicine from the media, and 31%had learned of the preparation by

Ôword of mouthÕ. One patient hadobtained the information from theInternet.

In response to the question regarding

side-effects of the herbal medicine theywere taking, 42 (89.4%) of patientsreplied that they did not know of any

potential side-effects.

In general, the patient had notinformed their family practitioner thatthey were taking a herbal product,with only 29.8% stating that their

doctor was aware, and 83% said thatthe surgical team was also unaware,many patients commenting that they

had not been asked about alternativemedicines.

Case reports in the current literature

have questioned the safety of manyherbal remedies [1]. In particular, sev-eral have been implicated in serious

drug interactions with prescribed med-ications [2, 3]. Recent studies carriedout in the United States have shownthat signi®cant numbers of patients are

taking herbal medicines in the pre-operative period [4, 5]. Data from thesestudies suggest that up to 22% of

patients are using herbal preparations.It is clear from the results of this study

that a substantial proportion of patients

presenting for day-case surgery aretaking herbal medicines. The preva-lence of 12.14% in our study is lower

than North American ®gures, but stillrepresents over 1 in 10 patients. In1998, Eisenberg et al. estimated that onein ®ve US adults taking prescription

medications were also using herbalmedicines and risked developingadverse interactions between herbal

medicines and prescription drugs [4].Our study suggests that 34% of pre-operative patients are using concomi-

tant medications.In the present study, less than one

®fth of those taking herbal prepara-tions had informed medical staff of this

fact. This may be due to the com-monly held belief that herbal productsare natural and are therefore safe. This

is a matter for concern, as many ofthese products are potent and poten-tially harmful. Many patients com-

mented that they had not been askedspeci®cally about herbal remedies,vitamins or minerals. We would sug-

gest that questions relating to the useof alternative therapies should nowbecome a standard part of the patient'sadmission history and pre-operative

assessment.At present the particular risks associ-

ated with herbal medicines in relation to

anaesthesia are unclear. However,

awareness of some of the known effectsof some of these preparations shouldhelp us, at least in theory, to predictpossible problems.

The most important side-effects andinteractions to be aware of are cardio-vascular instability, bleeding and pro-

longation of anaesthesia. Much of theinformation available on herbal medi-cines is at present anecdotal and awaits

further study. However, given thatthese preparations do not require aproduct license, it is unlikely that they

will ever be subjected to the samerigorous study as conventional pharma-ceutical preparations. Indeed, concernsover safety have precipitated calls for

licensing legislation to be extended toherbal medicines [6]. Recently, the IrishMedicines Board has recommended that

the herbal medicine St. John's Wort bemade subject to prescription control [7].

In conclusion, patients are taking

herbal medicines on a regular basis,frequently in conjunction with pre-scribed medication. In general, they

are not aware of any possible side-effects, and therefore regard thesepreparations as innocuous. There iscertainly a potential for signi®cant

interactions and side-effects to occur,and we should take this into accountin our pre-operative assessment [8].

Further research into this area will benecessary before ®rm recommendationscan be made regarding herbal medi-

cines and their effects on anaesthesiaand surgery.

S. Crowe

G. Fitzpatrick

M. F. Jamaluddin

Adelaide, Meath and National

Children's Hospital,

Dublin 24, Ireland

E-mail: [email protected]

References1 Windrum P, Hull DR, Morris TC.

Herb±drug interactions. Lancet 2000;

355: 1019±20.

2 Piscitelli SC, Burstein AH, Chaitt D,

Alfaro RM, Falloon J. Indinavir con-

centrations and St. John's wort. Lancet

2000; 355: 547±8.

3 Ruschitzka F, Meier PJ, Turina M,

Luscer TF, Noll G. Acute heart

Anaesthesia, 2002, 57, pages 183±208 Correspondence......................................................................................................................................................................................................................

Ó 2002 Blackwell Science Ltd 203

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transplant rejection due to St. John's

wort. Lancet 2000; 355: 548±9.

4 Tsen LC, Segal S, Pothier M, Bader AM.

Alternative medicine use in presurgical

patients. Anesthesiology 2000; 93:

148±51.

5 Eisenberg DM, Davis RB, Ettner SL

et al. Trends in alternative medicine use

in the United States, 1990±97. Journal of

the American Medical Association 1998;

280: 1569±75.

6 De Smet PAGM. Should herbal medi-

cine-like products be licensed as medi-

cines. British Medical Journal 1995; 310:

1023±4.

7 Irish Medicines Board. 9th edn. Drug

Safety Newsletter February 2000.

8 Ang-Lee MK, Moss J, Yuan CS.

Herbal medicines and perioperative

care. Journal of the American Medical

Association 2001; 286: 208±16.

Overcoming dif®culties withpercutaneous tracheostomy

We read with interest the recently

published investigation of the BlueRhinoTM percutaneous tracheostomyset (Bewsher et al. Anaesthesia 2001;

56: 859±64). We note that one of theproblems cited was the fact that thetracheostomy created by the dilator was

not big enough to easily accommodate asize 8 Mallinckrodt ShileyTM tracheos-tomy tube. As we have been workingon the same intensive care unit from

which the paper originated, we feel itnecessary to communicate how thisproblem has been overcome. On

examination of the aforementionedtracheostomy tube, it is found to havean external diameter of 12.2 mm. If this

is substituted for a size 8 Portex Blue-line UltraTM, the passing of the tube ismore easily achieved. Not only does the

Portex tube have a smaller externaldiameter (11.9 mm), but it also has asofter and more malleable tip. It is alsosimilar to the ShileyTM tube in that it

retains the advantage of a detachableinner tube.

A. MacKillop

D. Acharya

Victoria Hospital,

Blackpool FY3 8NR, UK

Cheese, drug labels andanaesthetic room error

A recent editorial and correspondence

over several years draw attention todrug labelling and its importance in theavoidance of drug error in the anaes-

thetic room [1±4]. Labelling of thepackaging, ampoule and syringe areimportant but not unique factors in

anaesthetic room drug error. It is ofconcern that whilst other areas of errorin medicine undergo vigorous systems

analysis, we seem to be looking nofurther than the issue of labelling ± if wecould only get the label right, we wouldnever make a drug error. The mecha-

nisms of cognition and of cognitiveerror are well described elsewhere [5, 6].Should we not take a more analytical

approach to this problem rather than thesimplistic one that discussions aboutdrug labelling seem to invite?

Giving drugs in the anaesthetic roomis a classic example of latent error. Wehave been set up. What other group of

health professionals prescribe, dispenseand administer potentially lethal drugsto patients we may have met onlyminutes before without any system of

checking? Errors are going to happenno matter how careful we are. In thepast we may have been slow to

implement change, as one singlechange was not going to make thesystem perfect. Now, with understand-

ing of the ÔSwiss CheeseÕ phenomena,it is apparent that we must take everystep possible, no matter how small, tomake the system as good as we possibly

can whilst accepting that perfection isunlikely in a system that relies to anyextent upon individuals reading drug

labels.The drawing up of drugs is an

example of a skill-based action, which

as such is governed by patterns ofpreprogrammed instructions (schemata)that is largely subconscious. Skill based

errors are known as slips ± they areunintended actions. There are severalfactors, both endogenous and exo-genous, that make slips more likely

and could be avoided [5].Fatigue, sleep loss, alcohol, drugs and

illness are examples of endogenous

factors that are thought to make slips

more likely and are under the controlof the individual. Exogenous factors aremore dif®cult for the individual tocontrol. Overwork and stress are all

emotions we are familiar with, butshould we really be rushing to get anover-optimistic list ®nished? The envi-

ronment in the anaesthetic room isimportant. The temperature should beappropriate for both you and the

patient. Noise should be kept to aminimum and interruptions notallowed. Fear and anxiety are good

for you in moderation, but excessresults in under-performance. Theynormally arise when undertaking occa-sional practice or working in an unfa-

miliar environment. Departmentsshould not allow this to happen. It isimportant that we, as individuals,

realise that when we are angry we aremore likely to make a mistake. Bore-dom should be avoided, and breaks

during long cases facilitated.Many of us have developed patterns

of work that we consider to be safe

practice. Some are common sense,others more controversial. We shouldshare this information, encouragedebate and re-examine our own prac-

tice. For example, what practical stepscan be taken to avoid drug error in theanaesthetic room?

The standardisation of anaestheticroom drug cupboards is a ®rst step,removing those drugs that are not often

used and keeping drug stock centrally toavoid crowded cupboards. Only thedrugs in use speci®cally for that listshould be removed from that cupboard

by the anaesthetist and placed on thework surface. Drugs would be keptalphabetically, with no labels on the

shelf. No individual ampoule shouldever be put back into a box, and theyshould not be removed from the pack-

aging and kept elsewhere. Ampoulesshould be for single use only and not leftopen on the bench. When a supplier for

a particular drug is changed, each indi-vidual anaesthetist should be informedand warning labels attached to the drugboxes. It has been assumed that best

practice is that the anaesthetist who isgoing to administer the drugs shoulddraw them up. Perhaps the Operating

Department Assistant should draw them

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204 Ó 2002 Blackwell Science Ltd

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up and we check them? The diluting ofdrugs is a potential source of error. Thecommonest slip is giving a wrong drugbut in the right sized syringe [7]. Should

we draw all induction agents up into a20-ml syringe, all neuromuscular block-ing drugs into a 5-ml syringe and all

analgesics into a 2-ml syringe? If localanaesthetic is to be used, it should bedrawn up and used before the induction

agent is drawn up. Conversely, if theblock is to be performed after induc-tion, draw the local anaesthetic up only

once the patient is asleep.

These suggestions ignore the issues

that surround labelling, and individually

will not prevent drug error. However,

taken together, they may work syner-

gistically to make error much less likely.

Anaesthetic department practice, phar-

macy policy, theatre management, the

physical environment we work in and

our own well being all play a role in

anaesthetic room drug error. Until we

accept the multifactorial causes of these

errors, they will continue to happen

with alarming frequency and potential

for disaster.

C. P. Leng

Northampton General Hospital,

Northampton NN1 5BD, UK

References1 Birks RJS. Safety Matters. Anaesthesia

2001; 56: 823±4.

2 Nott MR. Misidentification, in-filling

and confirmation bias. Anaesthesia 2001;

56: 917.

3 Dill-Russell P, Dhileepan S. Sodium

citrate bottles. Anaesthesia 2001; 56:

401±2.

4 Heneghan CP. Drug labelling ± a place

for colour coding? Anaesthesia 1996; 51:

600±1.

5 Leape LL. Error in Medicine. Journal of

the American Medical Association 1994;

272: 1851±7.

6 MerryAF, Webster CS. Labelling and

drug administration error. Anaesthesia

1996; 51: 987±8.

7 Fasting S, Gisvold SE. Adverse

drug error in anaesthesia, and the

impact of coloured syringe labels.

Canadian Journal of Anaesthesia 2000; 47:

1060±7.

A±Q alphabetic anaestheticassessment algorithm

As a SHO, I tend to forget to ask certainquestions or do certain assessments. Itherefore developed an alphabetic

anaesthetic assessment algorithm to helpme do a complete assessment (Table 5).With experience, the algorithm takesabout 3 min to complete for an ASA I

patient. Using the algorithm also helpedin the Primary OSCE exams.

As a more senior anaesthetist, I am

less likely to forget the important pointsof an anaesthetic assessment. However,all too often, missing notes or anaes-

thetic charts mean that I have toannotate my anaesthetic assessmenton my theatre list. An abbreviated

alphabetic anaesthetic assessment algo-rithm helps me maximise the limited

Table 5 The A±Q Anaesthetic Assess-ment Algorithm. Classi®cation A±Q algorithm Comments (e.g. or esp)

Biodata AgeBody weight

Surgical issues Current problem and procedureTime of damage Time between food and trauma

Anaesthetic history Exposure to previous anaestheticsFamily history

Medical problems Gastric problems Re¯ux, hiatus hernia,gastritis ¤ ulcer

HistoryAsthma­BPCardiacDiabetesEpilepsyFags per dayGlasses of alcoholHospitalisationsInfections URTI, sepsis

Anaesthetic assessment Joint problems Neck, back, arti®cial jointsKitchenware Dentition, Mallampati

and Wilson scoringLast meal and drink

Interactions MedicationsNoxious Allergies

Obs Obs and labsDiscussion Plan

postpone for optimisation?premedicationpre-operativeperi-operative e.g. invasive monitoringpostoperativeQuestions? Ask patient for questions

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space on the theatre list. For example,for an ASA I patient, I may write E 4

GHI0 JKL 4 M0 N0 P NSAID PR, inany available space. The annotation has

the bene®t of reminding me of thequestions I asked or did not ask, whenthe anaesthetic chart ®nally turns up for

documentation. In fact, the annotationmay be used as a standard form ofdocumentation on anaesthetic charts, if

there is general agreement within thereader's department to do so.

I therefore submit the A-Q anaes-

thetic assessment algorithm for fellowanaesthetists to use and adapt.

M. Lim

Northampton General Hospital,

Northampton NN1 5BD, UK

E-mail: [email protected]

An unusual complication offasting

We would like to describe an unusualcomplication of fasting in children: An18-month-old child was admitted to

our day case unit for a gastroscopy. Inaccordance with our usual practiceEMLA cream was applied to the back

of the hand of the child and coveredwith a non-occlusive dressing. Theparents had adhered to our guidelines

of fasting the child pre-operatively.During the endoscopy procedure

performed under general anaesthesia,

the gastric fundus was visualised and itwas noted that the fundus was coveredwith a large piece of the non-occlusivedressing. This was then removed with

no ill after effects.It is a usual practice to apply EMLA

cream to children's hands in prepara-

tion for theatre. The non-occlusivedressing is applied to improve theeffectiveness of the cream and to hold

the cream in place. In young children,the EMLA cream and the non-occlu-sive dressing are then covered by a

bandage in order to prevent the childremoving the cream and the dressingaltogether. In this case, as was laterrevealed, the patient Ôslipped through

the netÕ and a bandage had not beenapplied.

Children of this age have a tendency

to place things in their mouth, and in

this case the dressing was torn andswallowed. This action could havepotentially disastrous consequences ifthe dressing was inhaled as a foreign

body causing upper airway obstruction,which is a real possibility in childrenwith small airways.

Extra care should be taken to ensurethat the occlusive dressing is safelycovered with an additional bandage in

young children if Emla cream is con-sidered necessary, especially in hungrychildren!

J. Easby

B. McLain

S. JuÈrgens

University Hospital of North Tees,

Stockton TS19 8PE, UK

Can propofol cause keratitis?

I read with interest the recent letter

(Ameen et al. Anaesthesia 2001; 56:1017±18) describing a possible compli-cation of propofol in an anaesthetist. Iwould like to report a similar incident,

which I experienced a few months agowhen I was anaesthetising an electivesurgical patient for herniorrhaphy.

In common with Dr Ameen, whilst Iwas injecting propofol into the injec-tion port of an intravenous cannula,

most of the propofol splashed into myeyes. Immediately I experienced anintense burning sensation and was

blinded for a few minutes. I was thesole anaesthetist and unfortunatelycould not proceed with the anaesthetic.Therefore, help was summoned and

another anaesthetist had to completethe anaesthetic. As regards to my eyes, Iimmediately washed them with tap

water and later rinsed them with sterilewater. The burning gradually subsidedover a period of a few minutes and I

did not suffer any ill effects from thepropofol.

The above incident fortunately

occurred in the daytime when helpwas immediately to hand. Furthermore,we had a trainee ODA, who went tocall for assistance, while the Senior

ODA maintained the patient's airwaywhile waiting for another anaesthetist.A critical incident form was completed,

and later discussed in the local Morbid-

ity and Mortality meeting. The majorconcern expressed was had such anincident occurred in the night, it mighthave resulted in a more serious incident

with a partially anaesthetised patient andan incapacitated anaesthetist.

M. B. Reddy

Northampton General Hospital,

Northampton NN15BD, UK

The incidence of pulmonaryoedema in ®t patients ofAfrican origin

I would like to report three cases ofpulmonary oedema in ASA 1 patients ofAfrican origin. I believe that it is easier

to cause pulmonary oedema in medi-cally ®t patients of African origin thanpatients of other races.

The ®rst case was a 46-year-old,

92 kg male who developed pulmonaryoedema following a short episode oflaryngospasm on emergence from an-

aesthesia. He had had elective handsurgery and had received 1 L intrave-nous ¯uid during 2 h of surgery.

The second case was a 28-year-old,63 kg female who had an electiveCaesarean section under general anaes-

thesia. She received 2.5 L intravenous¯uid during 1 h of surgery duringwhich there was 1.5 L blood loss. Shedeveloped pulmonary oedema post-

operatively.The third case was a 34-year-old,

61 kg male who had emergency surgery

to drain a scrotal haematoma followingan inguinal hernia repair. Pre-opera-tively, he was dehydrated, and he

received 2 L intravenous ¯uid during1 h of surgery. Postoperatively he alsodeveloped pulmonary oedema.

In each case the diagnosis was con-

®rmed on X-ray, treatment was withfurosemide and oxygen, and resolutionoccurred within 24 h. Each patient was

looked after by myself and was recordedin a log of unusual cases, which I havekept for 10 years. During that time, I

have anaesthetised approximately 5000ASA 1 patients. I estimate that 500 ofthese have been of African origin

including the three cases reportedabove. I have had no unexpected cases

Correspondence Anaesthesia, 2002, 57, pages 183±208......................................................................................................................................................................................................................

206 Ó 2002 Blackwell Science Ltd

Page 25: Just who do they think we are?

of pulmonary oedema in the remaining4500 patients, who have been mainly ofEuropean, Asian, or Oriental origin.

Although in each of the three cases

reported above there were some pro-voking factors to cause pulmonaryoedema, it seems surprising that each

patient was of the same racial group. Byapplying the Fisher exact test to thefrequency table (Table 6), the level of

statistical signi®cance is given asp < 0.001.

I have found no evidence in the

literature to support my contention thatit is easier to cause pulmonary oedemain ASA 1 patients of African origin thanother patients, although some col-

leagues have provided anecdotal evi-dence to support my hypothesis. Iwould be interested if readers have any

comments.

B. Norman

Chelsea and Westminster Hospital,

London SW10 9NH, UK

Preventing rubber stoppercoring

I read the recent letter about theaccidental injection of rubber bung

pieces into patients (Chikungwa.Anaesthesia 2001; 55: 828) and can offera solution. The problem is becomingmore common as many drugs now

come in a bunged vial. Although mostof these bungs are not made of latex,stopper coring can occur with any

rubber-topped vial. Manufacturers rec-ommend discarding any product wherecoring is thought to have occurred [1].

The problem usually occurs when alarge bore blunt drawing up needle isused. Instead of using a sharp needle,which increases the risk of needle-stick

injury to draw up drugs, a Ôvial access

cannulaÕ should be used. Such a cannulais manufactured by Becton-Dickinsonand Co.

The vial access cannula is attached to

the drawing up syringe and its coverremoved. The coloured plastic spike ofthe cannula is inserted through the

centre of the vial bung until the cannulashoulder reaches the vial bung. Thedrug is then withdrawn into the syringe.

The arrow tipped spike does not form arubber core and prevents any debrisbeing withdrawn with the drug. The

cannula is removed leaving the col-oured spike lodged in the bung fordispersal. This avoids the problems ofstopper coring, the subsequent discard-

ing of the drug and of needle stickinjury, protecting both patient andanaesthetist.

G. Nicol

Western Hospital,

Footscray, Victoria 3011, Australia

Reference1 Camegie C. Are we causing latex sen-

sitisation unknowingly? Anaesthesia

2001; 55: 828.

Non-English information onampoules and drug package-inserts

I was surprised on returning to my basehospital in London that some of the

everyday drugs used by anaesthetists hadforeign (non-English) labels on theampoules. Firstly, I noticed that glyco-pyrronium 0.2 mg, 1 ml ampoules were

labelled in German and bupivacaine0.5%, 10 ml ampoules were labelled inItalian. Essential information such as

drug name, concentration, volume andexpiry date were fairly obvious.

I then found that the drug package-

inserts (for both doctors and patients)were in German for the glycopyrroniumand Italian for the bupivacaine. Therewas no English translation immediately

to hand, although they were apparentlyavailable from the hospital pharmacy. I®nd the drug package-inserts a valuable

source of information for users as well asmedical students and other staff in train-ing, especially during theatre sessions.

I was wondering whether others hadhad similar experiences with ÔforeignÕampoules and if this was a subtle attemptby the powers-that-be to force NHS

staff to become more multilingual andpro-European!

G. Wearne

King's College Hospital,

London SE5 9RS, UK

E-mail: [email protected]

Anaesthetic history of a patient:250 anaesthetics in 30 years

We wish to present a unique case whohas experienced nearly 250 anaestheticsduring 30 years and has had an excep-

tional opportunity to observe thedevelopment of anaesthesia from apatient's perspective. We interviewedher following her 80th birthday and

240th anaesthetic.At the age of 3 years, our patient

accidentally ingested alkaline caustics,

which caused stricture of the upperoesophagus. The community doctorstarted dilations, and this procedure

was repeated frequently for 50 yearswithout any analgesia or anaesthesia.

ÔThe dilations were sometimes painful

and I was afraid of them, yet I don'tremember anything especially negativeabout them. Perhaps, even as a smallchild, I understood that they helped me

and afterwards I could eat again. Later,however, the stricture progressed anddilations were more dif®cult and painfulÕ.

The dilations were ®rst performedunder general anaesthesia in 1970.Concomitant diseases appeared along

with advancing age. Our patient hasgeneral arteriosclerosis, coronary heartdisease with seven myocardial infarc-tions (MI), arterial hypertension, diabe-

tes and dietary anaemia. Recently, theprocedures have often been postponedbecause of chest pain and fatigue.

The anaesthetic history of the patientis a good overview of the developmentof general anaesthesia practice. The ®rst

anaesthetics consisted of thiopental,pethidine, succinylcholine infusion andhalothane. From 1975 to 1982, there

was a period of Ôneurolept anaesthesiaÕ(fentanyl and droperidol). Through the

Table 6

Race Pulmonaryoedema

No pulmonaryoedema

African 3 497Non-African 0 4,500

Anaesthesia, 2002, 57, pages 183±208 Correspondence......................................................................................................................................................................................................................

Ó 2002 Blackwell Science Ltd 207

Page 26: Just who do they think we are?

use of several inhalation anaesthetics(en¯urane, iso¯urane and des¯urane),opioids (fentanyl and alfentanil) andmuscle relaxants (alkuronium, vecuro-

nium and atracurium), the recent meth-od has been propofol and remifentanilinfusions, sevo¯urane inhalation and

mivacurium.From the patient's point of view, the

major improvement has been in the

quality of recovery.ÔFalling asleep has always been easyand it has remained similar. Waking

up and the recovery period havechanged a lot during the years. Eventhough I am much older now, it iseasier to recover. Earlier it took a

week and I used to be very tired andkept forgetting things. Now it onlytakes 2 or 3 days, even though my

health is a lot worse. At best, I haverecovered in a day. Only lately, asmy health has deteriorated, have I

been afraid of the procedures. I havelearned to trust in you and I knowyou do your best. I am over 80-

years-old now and have done quitewell to get this far.ÕThe modern anaesthetic methods

allow safe anaesthesia to elderly patients

with multiple concomitant diseases.The ASA class of our patient hasprogressed from I to IV because of old

age, multiple MIs and other diseases.In spite of this, according to the anaes-thetic records, the peri-operative hae-

modynamic responses have remainedsimilar and a MI during an emergencylaparotomy has been the only majorcomplication.

Even though not actively examined,there has been no clinical indication of

organ toxicity, such as liver or renalfailure or bone marrow depression,following numerous exposures to, e.g.nitrous oxide or halothane [1, 2]. Dur-

ing the ®rst years, cognitive failurelasted for up to a week. The patientherself considered diazepam to be

responsible and later refused to have it.Halothane metabolites may also havedelayed recovery [3].

From the patient's point of view,falling asleep following the intravenousadministration of an anaesthetic has

been similar but the recovery periodhas improved markedly during threedecades. We do not know what mightbe the world record in the number of

anaesthetics experienced by one person.The experiences of our patient arecertainly unique, and we are grateful

for her comments.

L. Kotiniemi

S. Autio

K. Hyrynkangas

Oulu University Hospital,

FIN-90029 OYS, Finland

E-mail: leena.kotiniemi@ppshp.®

References1 Baden JM, Rice SA, Metabolism and

Toxicity. In: Miller RD, eds. Anesthe-

sia, 4th edn. Churchill Livingstone,

New York 1994, 157±84.

2 Kharash ED. Volatile Anesthetics:

Organ Toxicity. In: Atlee JL, ed.

Complications in Anesthesia.

Philadelphia: W.B. Saunders Co 1999,

57±9.

3 Harkin CP. Delayed Emergence. In:

Atlee JL, ed. Complications in Anesthesia.

Philadelphia: W.B. Saunders Co 1999,

189±91.

Just who do they think we are?

National Anaesthesia Day has been and

gone, hopefully leaving the generalpublic with an improved awareness ofthe role of the anaesthetist. Whilst all

this is highly commendable, I can'thelp feeling more concerned about theastonishing degree of ignorance exist-ing much closer to home. Sadly, it

appears that many of our colleaguesalso have very little idea of our practiceor even of our quali®cations. As an

illustration, I present three recent inci-dents.

A ward nurse accompanying a patient

to theatre remarked that she too wouldlike to become an anaesthetist and askedif she would need to have A-levels.

After a successful cardioversion car-ried out in the anaesthetic room, themedical houseman had second thoughtsabout leaving and asked the anaes-

thetist if she would like a doctor toremain with her while the patient wokeup.

An anaesthetist from the intensivecare unit whilst reviewing a patient onthe ward was told by nurses that he

could not write on the drug chart asÔonly doctors are allowed to do thatÕ.

I am sure that many readers will havesimilar examples. Perhaps next year we

need to hold National Anaesthesia dayinside the hospital!

R. Spencer

Gloucestershire Royal Hospital,

Glouceter GL1 3NR, UK

Erratum

Adenotonsillectomy in children: a comparison of morphineand fentanyl for peri-operative analgesia. Anaesthesia 2001; 56:

1193±7.

We wish to apologise for an error which was printed inthis paper. Drs Streets and Johnson were identi®ed as

Specialist Registrar and Senior House Of®cer in Anaes-thesia respectively. Dr Streets is in fact the Senior HouseOf®cer and Dr Johnson the Consultant Paediatric Anaes-

thetist at Derriford Hospital, Plymouth PL6 8DH, UK.

Correspondence Anaesthesia, 2002, 57, pages 183±208......................................................................................................................................................................................................................

208 Ó 2002 Blackwell Science Ltd