Abstracts of free papers presented to the Obstetric Anaesthetists” … · 2011-08-10 · Abstracts of free papers presented to the Obstetric Anaesthetists’ Association meeting,

lnternotional Journal of Obstetric Anesrhesia (1999) 8, 191-218 0 1999 Harcourt Brace & Co. Ltd

Abstracts o f free papers p resented to the Obstetric Anaesthetists” Association mee ting in L iverpool, UK: 22-23 April 1999

ORAL PRESENTATIONS

1. Initiation of mobile regional analgesia in labour: a comparison of the spinal and epidural routes.

D.J.A. Vaughan, J.S. Nickells, N.K. Lillywhite, B. Loughnan, M . Hasan, I?N. Robinson. Department of Anaesthesia, Northwick Park Hospital, Harrow, M iddlesex, UK

Introduction: Combined Spinal/Epidural (CSE) techniques for labour analgesia have become common in recent years, and are said to provide faster onset than epidurals. lx2 We compared the mob ile epidural and spinal starter regimens used in our unit to assess if initial subarachnoid injection conferred a significant advantage over a sole epidural technique.

Method: 142 patients over 36 weeks gestation, with singleton cephalic presentation and in active labour were recruited. After randomisation, group 1 received a CSE (2.5 mg bupivacaine plus 25 p.g fentanyl; 1.5 m l total) and group 2 were given an epidural (12.5 mg bupivacaine plus 50 ug fentanyl; 10 m l total). The m idwife was unaware of the technique used, and noted the time of the first ‘comfortable’ contraction. This was taken as a contraction without pain regardless of other sensation. Maternal b lood pressure and fetal heart rate were recorded at 5 m in intervals for 30 m in. After this time motor blockade (modified Bromage) and proprioception (hallux position sense) were tested. Patients with persistently painful contractions were treated appropriately. T ime to first top up was noted.

Results: The two patient groups did not differ significantly with respect to age, parity, gestation, cervical dilation, induction or augmentat ion of labour, or incidence of pre-eclampsia. 69 patients

were randomized to CSEs and 73 to epidurals. There were nine failures ( inadequate analgesia after 30 m in) in each group. These 18 cases were removed from the data set, leaving 124 patients. The time to onset of first comfortable contraction was 10 m in (SD 5.7) for the CSE group, and 12.1 m in (SD 6.5) for the epidural group. This difference was not significant. There was a greater incidence of motor weakness and loss of joint position sense in the CSE group (P < 0.01 in both cases). T ime to first top up was similar in the two groups, at about 80 m in.

Discussion: All procedures were carried out by specialist registrars or consultants, and success rates for adequate analgesia approached 90% in both groups, a figure comparable with other studies.* Spinal starters have been advocated as ideal for initiation of mob ile regional analgesia.‘,* The increased risk of proprioceptive and motor dysfunction we found decreases the safety and ease of mob ilization. Our technique of assessment measures the outcome the patient wants from analgesia, rather than block height or complete sensation loss. We feel that a non significant difference in mean onset time of 2 m in in a labour lasting many hours does not justify the increased risk of pruritus, nausea and vomiting associated with intrathecal opioids, as well as increased cost in equipment. In conclusion, we find no advantage in the use of the CSE for routine initiation of labour analgesia.

REFERENCES

1. Collis RE, Davies DW, Aveling W . Randomised comparison of combined spinal epidural and standard epidural analgesia in labour. Lancet 1995; 345: 1413-1416.

2. Collis RE, Baxandall ML, Srikantharajah ID, Edge G, Kadim Y, Morgan B. Combined spinal epidural (CSE) analgesia: technique, management, and outcome of 300 mothers. International Journal of Obstetric Anesthesia 1994; 3: 75581.

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192 International Journal of Obstetric Anesthesia

2. Further development of a risk assessment protocol for the selective administration of H, receptor blockade in labour

B. Agarwal, T. Palit, S. Malik, A.C. Norton Department of Anaesthesia, Pilgrim Hospital, Sibsey Road, Boston, PE21 9QS, UK

Introduction: We have previously reported results from an audit of a midwife managed protocol for continuous risk assessment in labour and the selective administration of ranitidine to mothers graded as high risk.’ This protocol achieved a high sensitivity in accurately identifying high risk patients who ultimately required intervention, but the protocol was of low specificity. This study was designed to evaluate the effectiveness of a revised protocol.

Methods: Following a multi-disciplinary audit meeting where results from the first study were discussed, a number of revisions of the risk assessment protocol were agreed, principally relating to prostaglandin induction, augmentation of labour and use of a single dose of pethidine in the absence of any other risk factor. Low-risk women were allowed to feed from an approved list. High-risk women were given 6 hourly ranitidine and restricted to limited clear fluids.

Results: To date 477 mothers have been assessed under the revised protocol. Delivery outcomes classified by final risk grading are shown in the table. Sensitivity of the protocol high-risk grading for intervention in delivery was 92.9% with a specificity of 71.2%. In the previous study corresponding values were 94.2% and 32.2%. All mothers who had a caesarean section (n = 62) had a final high risk grading and 59 (95.1%) of these received ranitidine as per the protocol.

Table Delivery outcomes according to final risk grading

Delivery outcome SVD Instrumental Other Caesarean section

Final risk grade Low 250 9 0 0 High 101 41 8 62

Discussion: Use of the risk assessment protocol continues to achieve a high sensitivity in identifying mothers who are at risk of an obstetric intervention and ensures that such mothers receive H, receptor blockade with an acceptable degree of reliability.

ACKNOWLEDGEMENT

The authors wish to thank the midwives at Pilgrim Hospital for their continued support and enthusiasm.

REFERENCES

1. Norton A C, Agarwal B. Evaluation of a midwife managed risk assessment protocol for selective administration of H, receptor blockade in labour. International Journal of Obstetric Anesthesica 1998; 7: 202-203

3. Airway obstruction with cricoid pressure

E.L. Hartsilver, R.G. Vanner Gloucestershire Royal Hospital, Gloucester GLI 3NN UK

Introduction: If the anaesthetist fails to intubate the trachea, ventilation of the lungs is imperative. Cricoid pressure applied with a force of 44 N may prevent ventilation’ but less (30 N) is still adequate to prevent regurgitation.2 Cricoid pressure applied in an upward and backward direction may improve the view at laryngoscopy.3 This study investigates whether 30 N of force applied during cricoid pressure, either in a conventional manner or an upward and backward direction, also cause airway obstruction.

Method: Ethics committee approval and consent were obtained. Patients were female, not pregnant, without risk of regurgitation and about to undergo elective surgery. Standard monitoring and anaesthesia were used. Following muscle relaxation patients were ventilated via a face mask and oral airway with an inspired tidal volume of 900 ml. The expired tidal volume (largest of three breaths) and inflation pressure were recorded with cricoid pressure applied in four ways: no cricoid pressure, 44 N of cricoid pressure, 30 N of cricoid pressure, 30 N of cricoid pressure applied in an upward and backward direction. These were in a random order and blinded from the investigator. The trachea was intubated and the expired tidal volume recorded again. Simulated cricoid pressure was practised on a weighing scale at 3.06 kg (30 N) and 4.5 kg (44 N) before each case then blindly reapplied and recorded after each case. Expired tidal volume was measured with the same Wrights spirometer accurate with a gas flow of 10 L/min. An expired tidal volume of less than 200 ml was taken to indicate airway obstruction. Statistical analysis comprised of comparison of paired proportions.

Results: Fifty-two women were studied, median age 33 years (range 21-67), weight 64 kg (range 44-108). Mean forces applied to the scales were 3.0 kg (range 2.8-3.6, SD 0.2) and 4.4 kg (range 3.6-5.2, SD 0.34). Airway obstruction occurred in no subjects without cricoid pressure, 18 (35%) with 44 N, 1 (2%) with 30 N and 29 (56%) with 30 N cricoid pressure in an upward

Abstracts of free papers presented to the Obstetric Anaesthetists’ Association meeting, April 1999 193

and backward direction. Cricoid pressure applied with a force of 30 N is less likely to cause airway obstruction than if applied with 44 N (P = 0.0001). Cricoid pressure with a force of 30 N is less likely to cause airway obstruction if it is applied conventionally rather than in an upward and backward direction (P < 0.0001).

Conclusion: Cricoid pressure applied with a force of 44 N can cause airway obstruction. If cricoid pressure is applied with a force of 30 N airway obstruction occurs less frequently unless the force is applied in an upward and backward direction.

REFERENCES

1. Allman K G. The effect of cricoid pressure application on airway patency. Journal of Clinical Anesthesia 1995; 7: 1977199.

2. Vanner R G, Pryle B J. Regurgitation and oesophageal rupture with cricoid pressure: a cadaver study. Anaesthesia 1992; 47: 132-m735.

3. Vanner R G, Clarke P, Moore W J, Raftery S. The effect of cricoid pressure and neck support on the view at laryngoscopy. Anaesthesia 1997; 52: 896900.

4. The use of TED stockings and sequential compression device to prevent spinal hypotension during caesarean section

PD. Sutherland,* M.Y.K. Wee,* P. Weston-Smith,* T. Skinner,* P. Thomas? *Department of Anaesthesia, Poole Hospital NHS Trust, Poole, BHl5 2JB, fMedica1 Statistics Department, Bournemouth University, Bournemouth BHl 3Lz UK

Introduction: Maternal hypotension is the commonest complication of spinal anaesthesia for caesarean section. Mechanical devices applied to the lower limbs provide an attractive method of preventing venous pooling. We have studied the use of thromboembolic deterrent (TED) stockings and found them to be of equivocal benefit.’ Esmach bandages have proven efficacy,* but are difficult to apply and can create high pressures. We present the results of a randomized controlled trial to determine whether an active sequential compression device in conjunction with TED stockings may prevent spinal hypotension.

Methods: We obtained local ethics committee approval. One hundred ASAl women presenting for elective caesarean section were studied. Fifty-one women received TED stockings and a sequential compression device (SCD) [Kendall, that creates a pressure of 40

cmH,O in the foot followed by the calf and thigh within 45 s cycles. Forty-nine women received neither TED nor SCD and acted as a control group. Before anaesthesia a preload of 20 ml/kg Hartmann’s solution was administered and baseline non-invasive blood pressure determined. Subarachnoid block to T5 was established with 1.8-2.2 ml of heavy bupivacaine (dependent upon maternal height) with 0.3 mg diamorphine. Blood pressure was measured every min for 20 min and if c 100 mmHg or 20% below baseline, ephedrine 3 mg i.v. was administered. The two groups were compared for differences in systolic, mean and diastolic blood pressure (student t-test), ephedrine requirements (Mann Whitney U-test), adverse maternal events and condition of the newborn.

Results: The groups were equivalent for age, height, weight, baseline blood pressure, level of sensory block, adverse effects, Apgar score at five minutes and cord blood gases. Women in the SCD/TED group required a median 3 mg ephedrine compared with 6 mg in the control group (P = 0.08). However, there were 46 departures from the protocol (an error rate of 2%). On 17 occasions (eight control, nine SCD/TED) ephedrine was given when it was not indicated and on 29 occasions (19 control, 10 SCD/TED) it was not given when it should have been. By analysing the time to first hypotension, rather than the response to hypotension, the effect of departures from protocol can be minimized. Kaplan-Meier survival analysis of the data shows that subjects in the control group are 1.8 (CI; 1.1-2.9) times more likely to have a hypotensive episode than subjects in the TED/SCD group (P = 0.02, log rank test). The difference persisted after adjustment for age, height, weight, and base line SAP using Cox’s proportional hazard regression.

Conclusion: The SCD in combination with TED stockings results in a small, but statistically significant reduction in the chance of developing hypotension following spinal anaesthesia for caesarean section. We do not feel that this difference is great enough to justify the use of SCD routinely.

REFERENCES

1.

2.

Thromboembolic deterrent stockings fail to prevent hypotension associated with spinal anaesthesia for elective caesarean section. International Journal of Obstetric Anesthesia 1996; 5: 172-175. Bhagwanjee S, Rocke DA, Rout CC Koovarjee RV Brijball R. Prevention of hypotension following spinal anaesthesia for elective caesarean section by wrapping the legs. Br J Anaesth 1990; 65: 819-822.


5. Caesarean section for placenta praevia; a retrospective study of anaesthetic management.

N. Parekh, SW. Husaini, I.F. Russell Hull Maternity Hospital h Castle Hill Hospital, Department of Anaesthetics, Castle Hill Hospital, Castle Road, Cottingham, East Yorkshire, HU16 SJQ, UK

Introduction: Placenta praevia is a major causes of massive obstetric haemorrhage and can result in increased maternal, fetal and neonatal morbidity or mortality. Anaesthesia for caesarean section for placenta praevia is controversial. Many anaesthetists feel strongly that general anaesthesia is mandatory for placenta praevia’ but regional anaesthesia may have advantages. In a retrospective analysis we sought any association between maternal morbidity and anaesthetic technique for placenta praevia.

Methods: Cases of placenta praevia were identified from labour ward and theatre registers. Placental position, history of vaginal bleeding, emergency or elective caesarean section, method of anaesthesia, grade of anaesthetist, estimated blood loss, blood transfusion, pre- and postoperative haemoglobin (Hb) and haematocrit (Hct) and anaesthetic complications or comments were recorded for each case.

Results: We identified 307 cases between January 1984 and December 1997. Overall 58% were started with regional anaesthesia; 136 single shot spinal, 1 CSE and 41 catheter epidurals. Four regional blocks were converted to GA (Table). GA was used more for emergencies than electives: 63% v 22%. Consultants used RA more often than trainees: 42% v 26% for emergencies and 8 1% v 73% for electives. Preoperative Hb & Hct were similar in RA and GA but postoperative Hb & Hct were higher, and the number of transfusions were fewer with RA. Five patients (all grade IV praevia) had hysterectomies: two had GA throughout; two had spinal for caesarean section but GA for subsequent hysterectomy (due to prolonged surgery), one had spinal anaesthesia for caesarean section and hysterectomy. Although these women had

Table Type of caesarean section, grade of placenta praevia and anaesthesia.

Total Grade 1 Grade 2 Grade 3 Grade 4

El Em El Em El Em El Em GA 6 16 8 25 12 40 7 17 131 RA 17 10 45 19 36 22 17 8 174 RA% 74% 38% 85% 43% 75% 35% 70% 32% 57%

multiple transfusions, intravascular volume and blood pressure were well maintained. Two patients had unrelated postoperative problems: one had pulmonary embolism on day 10; one had cerebral thrombosis with hemiparesis on day 17. Both recovered fully.

Conclusion: This audit provides no evidence that management of caesarean section for placenta praevia is harder with RA than GA and the outcome is no better with GA than RA. Whatever the anaesthetic technique, preparations must be made to contend with sudden blood loss. Our data support the suggestion that there is no reduction in maternal safety with RA. Moreover, in haemorrhage sympathetic blockade induced by RA may preserve gut mucosal and renal function by maintaining splanchnic and renal prefusion.*

REFERENCES

1.

2.

Crawford JS. Obstetric Analgesia and Anaesthesia. Edinburgh, Churchill Livingstone 1984; pp 109-l 10. Shibata K, Yamamoto Y, Murakami S. Effects of epidural anesthesia on cardiovascular responses and survival in experimental hemorrhagic shock in dogs. Anesthesiology 1989; 71: 953-959.

6. A comparison of vasoactivity between levobupivacaine and bupivacaine

D. Burke, M. MacKenzie, D.J. Newton,* F. Khan,* G McLeod, J J F Belch,* J Bannister Departments of Anaesthesia and *Medicine, Ninewells Hospital, Dundee, UK

Introduction: Stereoisomerism and drug concentration both influence the vasoactive properties of local anaesthetic agents. The effect of a local anaesthetic on the vasculature can be determined using intradermal testing.’ The effect can be quantified with Laser Doppler Perfusion Imaging (LDPI). The LDPI (Moor Instruments, UK) can scan an area of skin, thus enabling simultaneous comparison of blood flow changes at different sites with computer software providing image display and analysis. We used this technique to compare the vasoactivity of racemic bupivacaine and levobupivacaine.

Method: A double-blind, randomized, placebo- controlled study was performed on eleven male non- smoking volunteers. Observations were recorded in a room thermostatically controlled at 22°C. Different doses of each drug were randomly allocated to five sites on the volar surface of each forearm with a minimum separation of 3 cm. One site was untreated


and served as baseline. At the control site, 0.1 ml of 0.9% sodium chloride was injected intradermally via a 30 gauge needle. In the remaining eight sites, 0.1 ml each of 0.75%, 0.5%, 0.25% and 0.125% levobupivacaine and the same concentrations of racemic bupivacaine were administered. Baseline skin blood flow was determined before the injections. Skin blood flow was subsequently measured 2.5, 10,20,40, 60, and 90 min after injection. The total blood flow response over time (in arbitrary perfusion units) of each of the two drugs compared with that of saline was evaluated by calculating an index of the area under each curve (Fig. 1). Results were analysed using a two-way repeated measures analysis of variance, with a significance value less than 0.05 indicating a 95% confidence of difference.

Results: At all concentrations tested levobupivacaine exhibited greater vasoconstrictor activity than bupivacaine (P = 0.019) with the greatest difference at higher concentrations. A decrease in skin blood flow compared to saline was observed with levobupivacaine at concentrations less than 0.25%.

Total response to saline

0.125 0.25 0.5 0.75

Dose(%)

Figure Total response with respect to saline.

REFERENCE

1. Aps C, Reynolds F. An intradermal study of the local anaesthetic and vascular effects of the isomers of bupivacaine. Br J Clin. Pharmacol 1978; 6: 63-68.

7. The Pre-Eclampsia, Pulmonary Oedema, Cardiomyopathy Syndrome (PPOCS)

K. Pandya, E. Djabetey, T. Hankin, A. Stronnach, R.G. Wilkes Department of Anaesthesia and Intensive Care, The Royal Liverpool and the Countess of Chester Hospitals.

Introduction: Pulmonary oedema associated with pre-eclampsia is normally attributed to fluid overload, increased pulmonary capillary permeability, high

impedance left ventricular failure or a combination of these aetiologies. Evidence is presented that when such cases are routinely invested by echocardiography a cardiomyopathic element is frequently revealed. The recognition of PPOCS has important therapeutic and follow-up implications.

Methods: Ten patients who developed pulmonary oedema associated with pre-eclampsia, among 20 000 maternities at the Liverpool Women’s and Countess of Chester Hospitals, were investigated by serial echocardiography.

Results: Echocardiography demonstrated dilated hypodynamic left ventricular function in all cases, with varying degrees of right ventricular hypofunction and mitral and tricuspid valvular leakage consistent with a diagnosis of dilated cardiomyopathy. Ages ranged from 19 to 35 years, 50% were primiparous and onset of pulmonary oedema ranged from 14 days before delivery to 10 days after, 80% occurring post-partum. All but three cases were delivered by caesarean section and gestational length was less than 36 weeks in five cases. No mother received more than one litre of intravenous fluid before the onset of pulmonary oedema. All were normotensive, aproteinuric and free of cardiac disease at their first antenatal booking. Six were admitted for intensive care where invasive monitoring confirmed systolic dysfunction. Five required mechanical ventilation and ionotropic support. ACE inhibitor therapy was instituted in all cases. Six months post-partum, all were normotensive and aproteinuric. Six had made a full recovery of heart size and function with normal exercise tolerances. The remaining four were improving but with some cardiac deficit. Three had dilated hearts and two, with ejection fractions less than 60%, had dyspnoea on mild exertion.

Discussion: Peripartum cardiomyopathy (PCM) is a rare condition with an incidence of less than one per 15 000,’ an unclear aetiology and a poor prognosis, 50% suffering progressive deterioration of cardiac function leading to premature death without heart transplantation.2,3 The high incidence of one per 2000 in our series, together with resolution or improvement in all cases, suggest that PPOCS may be a distinct entity from PCM or a milder under diagnosed form. In some ways PPOCS bears the same relationship to PCM as HELLP does to acute fatty liver of pregnancy. Preeclampsia is a panendothelial disease causing multi-system dysfunction and failure, and it would be surprising if the heart were not occasionally the predominant target organ. Echocardiography is mandatory in all cases of preeclamptic pulmonary


oedema, irrespective of presumed cause, to determine any cardiomyopathic element, and thereby institute early treatment with ACE inhibitors. Our evidence suggests that although prognosis should remain guarded, a less pessimistic prognosis can be offered than that for PCM.

REFERENCES

1. Cunningham FG, Pritchard JA, Hankins GDV, Anderson PL, Lucas MJ, Armstrong KF. Peripartum heart failure: idiopathic cardiomyopathy or compounding cardiovascular events? Obstet Gynecol 1986; 67: 157-168.

2. Lampert MB, Lang RM, Peripartum cardiomyopathy. Amer Heart J 1995; 130: 860-870.

3. Witlin AG, Mabie WC, Sibai BM, Peripartum cardiomyopathy: an ominous diagnosis. Amer J Obstet Gynecol 1997; 176: 183-188.

8. Which solution for extending low dose epidural analgesia for emergency caesarean section?

D.N. Lucas, G. Ciccone, S.M. Yentis. Magi11 Department of Anaesthesia, Chelsea & Westminster Hospital, London, UK

Introduction: Low dose epidural regimens are commonly used in labour. However there is little information on the optimal method of extending such a block for the purpose of emergency caesarean section.lm3

Aim: To compare three commonly used local anaesthetic combinations for converting a low dose epidural into a block adequate for caesarean section.

Methods: After local ethics committee approval nulliparous labouring women with low dose epidurals were consented. Women proceeding to caesarean section were randomised to receive either bupivacaine 0.5% (B), lignocaine 2% with 1:200 000 adrenaline (L), or a 5050 mixture of 2% lignocaine/0.5% bupivacaine with 1:200 000 adrenaline (BL). Twenty ml of freshly prepared solution were administered over 3 min by an anaesthetist blinded to which solution was being used. The time taken for the block to reach T4 to cold bilaterally (from the end of injection) was measured. Other variables recorded included demographic data, details of the pre-existing block, maximum height of block, motor block, fluid and ephedrine requirements and quality of block during surgery assessed by the mother and anaesthetist using a visual analogue scale.

Results: 460 women consented and 90 women were randomised (30 per group). ANOVA, Fisher’s exact, x2 or Kruskall-Wallis tests were used as appropriate, with P < 0.05 denoting significance. There was no

40-

E 30- !E f $2 20-

E F

lo-

01 BuP Bup-Lig Lig

Figure Time to T4 (median, interquartile range and range).

difference in time to T4 (figure) or any other variable recorded. However, three general anaesthetics were required in group L and none in groups B or BL (P = 0.04).

Conclusion: Our results suggest that bupivacaine 0.5% would most reliably extend low dose epidural block for caesarean section. Any trend towards faster block with lignocaine is offset by the increased variability in onset time and number of general anaesthetics required (although numbers were small).

REFERENCES

1. Dickson MAS, Jenkins J. Extension of epidural blockade for emergency caesarean section. Anaesthesia 1994; 94: 636638.

2. Price ML, Reynolds F, Morgan BM. Extending epidural blockade for emergency caesarean section. International Journal of Obstetric Anesthesia 1991; 1: 13-18.

3. Gaiser RR, Cheek TG, Adams HK, Gutsche BB. Epidural lidocaine for cesarean section of the distressed fetus. International Journal of Obstetric Anesthesia 1998; 7: 2773 1.

9. A comparison of 0.125% levohupivacaine and 0.125% hupivacaine epidural infusions for lahour analgesia.

P Convery,* D. Burke,? L Donaldsont J. Eldridge,$ A. Young& D. Bogodg R. Russell,f G. McLeod,? K. Fitzpatrick* Anaesthetic Departments, *Belfast City Hospital, f Ninewells Hospital, Dundee, $John Radcliffe Hospital, Oxford, City Hospital, Nottingham, UK

Introduction: Levobupivacaine (L) is a new amide local anaesthetic, one of two optical isomers present in racemic bupivacaine (B). Both have similar local anaesthetic potency but animal models have shown that L has significantly less cardiotoxic potential than both dexbupivacaine and the racemic mixture.‘s2 This study compared the analgesic efficacy of continuous epidural infusions of L and racemic B 0.125% during labour.


Methods: Following local ethics committee approval and informed consent 112 patients were recruited into the study. Patients were ASA 1 or 2 and 1840 years, had chosen epidural analgesia for labour at full term and 55 cm of cervical dilatation. A lumbar epidural catheter was sited and analgesia established with a 4 ml test dose and a 6 ml bolus dose of 0.25% study drug allocated in a double blind manner. A further 5 ml bolus was administered 15 min later if the block was considered to be inadequate. When pain free and with a sensory block at TlO or above epidural infusions of L or B 0.125% at 12 ml hi’ were started. Verbal rating scale scores, VAS pain scores (OGlOO mm) and degree of sensory and motor blockade were recorded hourly until delivery. Additional top ups of 10 ml 0.25% study drug, to a maximum of 4, were given as required. Patients were withdrawn from the study if additional analgesics were required. Data were analysed by ANOVA and logistic regression methods.

Results: There were no differences in patient characteristics nor gestation, parity or degree of cervical dilatation between the groups. 80 patients completed the study with evaluable data. For the primary endpoint (% of pain-free hours), L and B were deemed equivalent (90% confidence limits -12.1 to +8.6). Sensory block spread was similar between the groups but there was an apparent trend towards less motor block with L. Apgar and NAC scores were similar in the two groups.

Table

Group L (n = 38) B (n = 42)

Pain free hours in 1 st stage, (‘Y0) 43.3 43.1 Mean dose (mg.h I) 28.3 21.2 Top up patients, n (%) 33 (87) 34 (81) Delivery outcomes SVD/Forceps/CS, n 1311619 2211 l/9

Conclusion: The results suggest that epidural infusions of L or B 0.125% provide comparable analgesia during labour.

REFERENCES

1. Mazoit JX, Boico 0, Samii K. Myocardial uptake of bupivacaine: II. Pharmacokinetics and pharmacodynamics of bupivacaine enantiomers in the isolated perfused rabbit heart. Anesth Analg 1993; 11: 477482.

2. Bardsley H; Gristwood R; Baker H; Watson N; Nimmo W. A comparison of the cardiovascular effects of levobupivacaine and rat-bupivacaine following intravenous administration to healthy volunteers. Brit J Clin Pharmacol 1998; 46: 2455249.

POSTER PRESENTATIONS

1. Post dural puncture headache (PDPH) in obstetric anaesthesia - a 16 year survey of 128 cases.

F. Hadji, M. Rao, J.S. Sprigge Arrowe Park Maternity Hospital, Wirrel, UK

Since Arrowe Park Maternity Hospital opened in 1982, more than 12500 epidural and about 1700 spinal anaesthetics have been performed. There have been 128 recorded cases of PDPH; 99 cases followed epidural, 27 followed spinal anaesthesia and two cases occurred after spinal plus epidural anaesthesia.

Zncidences: The overall incidence of PDPH following epidural analgesia was O.S”/o. This figure increased from 0.6% to a current 1.1%. Over the same time the annual number of epidurals fell from 1000 to 500.

The overall incidence of PDPH following spinal anaesthesia decreased from 7.2% prior to the introduction of pencil-point needles to 0.8%.

Rank of anaesthetist: Registrars performed 62% of the epidurals and caused 64% of the accidental dural punctures (ADP). Consultants, who performed 18% of the epidurals caused 9% ADP The incidences were 1.8% and 0.8% respectively.

Epidural technique: Loss of resistance to saline was used in 74% to identify the epidural space. Loss of resistance to air was used in 15%. The technique was not recorded in 11%.

Presentation of ADP: The ADP was caused by the needle in 38O/o, by the epidural catheter in 12% and 9% of patients presented with a spinal response to test dose. One patient suffered a total spinal, but made a full recovery. 34% of the inadvertent punctures presented later with PDPH in the puerperium.

Immediate management: The epidural was resited at a different level in 41 patients, in 34 the epidural was continued at the same level and 10 patients received intrathecal boluses. The procedure was abandoned in two patients.

Method of delivery: 38 patients delivered normally, another 38 had instrumental delivery and 15 patients needed caesarean section; this was precipitated by high block in two cases.


Headache following ADP: This occurred in 86% of the patients, it did not occur in 14%, despite known dural puncture. In 63% the headache presented within 24 h. The mean duration was 8 days, although in three patients it lasted over 1 year.

Management of headache: Initially all patients were treated conservatively and their symptoms were monitored daily. Epidural blood patches (EBP) were performed in 45 patients, mainly on the 3rd to 5th day. They were successful initially in 70%, but the headaches recurred in 50% after discharge. Three mothers received a second EBP and three developed signs of infection after EBl?

Patient satisfaction: 69 patients were satisfied with their management. Twelve patients were strongly dissatisfied and six of these undertook litigation.

Conclusions:

1) 2)

3)

4)

5)

The incidence of PDPH after epidurals was 0.8%. The incidence of spinal-PDPH fell from 7.2% to 0.8% with the introduction of pencil-point needles. 34% of inadvertent dural punctures were not recognised at time of insertion. 14% of patients with known ADP never developed headache. Epidural blood patches were successful in 50% of patients.

Cases in which they failed, treatment of PDPH proved to be difficult.

2. The standard recipe for manual removal of placenta under spinal anaesthesia and a low dose alternative

H. Brooks, J. Sherwin, A.E. May Leicester Royal Infirmary, Leicester, UK

Introduction: Is there a ‘standard recipe’ for providing regional anaesthesia for the procedure of manual removal of placenta? We surveyed consultant anaesthetists at the 1997 Guildford OAA meeting. Fifty-three questionnaires were returned. Forty-seven routinely used spinal anaesthesia Thirty-eight anaesthetists used hyperbaric bupivacaine 0.5%. The volume used ranged from 1 ml to 3 ml but 2 ml of the above solution was the ‘standard’ at that time. Two anaesthetists added fentanyl to this. We also asked what height of block was required and 40 out of 51 answers were between T8 and TlO (range T4 to T12). The above ‘standard’ anaesthetic produces significant motor block which is not welcomed by many mothers.

We wished to see whether reducing the dose of local anaesthetic and adding an opiate could reduce motor block but still provide adequate analgesia as in the spinal component of a CSE for labour.’ This has also been used successfully in the assisted conception unit of our hospital.2

Method: We gained ethics committee consent and studied a technique using 1.5 ml of 0.25% plain bupivacaine and 25 pg of fentanyl (2 ml). Fifteen mothers were recruited. One block was converted to a general anaesthetic but no record was made of the point at which this was done or whether any block had been achieved; therefore the data will be presented on fourteen mothers.

Results: All blocks were above TlO and extended down to the perineum. Motor block was measured both before and after the procedure.

0 = ability to move hips, knees and ankles 1 = inability to raise extended legs 2 = inability to flex knees 3 = inability to flex ankle and/or feet

No patient had a score greater than 2. Immediately postoperatively only one patient had a score greater than 1. Five patients had scores of 0 both pre- and postoperatively. A visual analogue score was recorded on all patients. One patient who had a technically difficult 50 min procedure had a VAS of 71. Otherwise scores ranged from 0 to 30 with 6 patients having pain scores of 0 or 1. Five patients were given additional analgesia. The procedure was acceptable to all the mothers.

Conclusion: This technique can achieve our aim of excellent analgesia with minimal motor block. However, five patients did receive additional analgesia This may be reduced by waiting a little longer for the block to establish. We would certainly recommend this block for co-operative mothers who are keen to retain mobility or if a CSE is used but at this point in time not for those who are unhappy or nervous about regional anaesthesia.

REFERENCES

Collis R E, Baxandall M L, Srikantharajah I D, Edge G, Kadim M Y, Morgan B M. Combined spinal epidural (CSE) analgesia: technique, management and outcome of 300 mothers. International Journal of Obstetric Anesthesia 1994; 3: 75-81. Tidmarsh MD, May AE. Spinal analgesia for transvaginal oocyte retrieval. International Journal of Obstetric Anesthesia 1998; 7: 1577160.

Abstracts of free namers nresented to the Obstetric Anaesthetists’ Association meeting, Auril 1999 199 I I I -

3. An audit of single-dose epidural diamorphine during emergency caesarean section under epidural anaesthesia.

N.J.D. McNeillis (SpR2), S.U. Khot (SpR2), G.K. Bloor (Consultant) Department of Anaesthesia, Eastbourne Hospitals NHS Trust, Eastbourne, UK

Introduction: Prolonged analgesia is obtained if neuraxial diamorphine is administered at the time of surgery.‘m3 A recent study showed prolonged effect with epidural diamorphine given at the first request for pain relief after caesarean section under spinal but not epidural anaesthesia.4 It was suggested that the prolonged analgesia was due to diamorphine entering the cerebrospinal fluid via the dural hole. We routinely administer single-shot epidural diamorphine during emergency caesarean section as part of an epidural technique; the dura remains intact.

Methods and results: During the last two years, 169 mothers received epidural analgesia in labour and proceeded to caesarean section. There were 44 exclusions (18 received general anaesthesia (GA), 8 planned and 10 conversions); 17 received spinal anaesthesia; 9 did not receive diamorphine. 125 mothers fulfilled the criteria for the audit but only 99 pain charts were found. The epidural catheter was removed at the end of surgery. Regular diclofenac and pm Co-dydramol were prescribed routinely. Pain scores were recorded as 0 (nil), 1 (mild), 2 (moderate) or 3 (severe), immediately on return to labour ward recovery and at 15 min, 30 min, 1 h, 2 h, 3 h, 4 h, 8 h, 12 h, 16 h, 20 h and 24 h. 91.6% of all pain-score data fields were completed. Postoperative analgesia was prolonged and excellent, see Table. No mother received morphine. Four mothers complained of severe pain after surgery; two did not received diclofenac (fears about asthma or preeclampsia), one with painful nipples and one with an inadequate regional block who refused general anaesthesia. Moderate or severe pain was successfully treated with Co-dydramol. Five mothers received anti-emetics and ten mothers received naloxone for moderate to severe itching.

Table Incidence and severity of pain during the first postoperative day

Symptom

Pain

Severity Percent of mothers

nil 25% mild 52% moderate 18% severe 4%

Discussion: Epidural diamorphine provided prolonged analgesia when given during emergency caesarean section under epidural anaesthesia. Additional postoperative opiate was unnecessary. Similar results were obtained using a combined spinal/ epidural technique (submitted work). Single-dose epidural diamorphine provides prolonged analgesia, whether or not the dura is intact.

REFERENCES

Roulson CJ, Bennett J, Shaw M, Carli E Effect of extradural diamorphine on analgesia after caesarean section under subarachnoid block. Br J Anaesth 1993: 71: 810-813. Graham D, Russell IF. A double-blind assessment of the analgesic sparing effect of intrathecal diamorphine (0.3 mg) with spinal anaesthesia for elective caesarean section. International Journal of Obstetric Anesthesia 1997; 6: 224-230. Bloor GK. Analgesia after caesarean section: systemic opiates are unnecessary if neuraxial diamorphine is given during surgery. International Journal of Obstetric Anesthesia 1998; 7: 190 (letter). Norman BJ, Yentis S. Analgesia produced by epidural diamorphine is better following caesarean section under spinal anaesthesia than under epidural anaesthesia. International Journal of Obstetric Anesthesia 1998; 7: 98-102.

4. Prospective analysis of the incidence of intraoperative pain during caesarean section under spinal anaesthetic.

B.M. Miller Department of Anaesthesia, University Hospital of South Manchesteu, UK

Introduction: Published series of caesarean sections performed under spinal anaesthesia report the incidence of pain up to 17%.’ I describe a large scale audit to review the incidence, severity and response to this event.

Methods: Data were collected in three hospitals in the Manchester region, all with large obstetric units. The study ran for 6 months in the second half of 1997. The case anaesthetist was asked to complete an anonymous form detailing the patients demographics, spinal technique, and recording the presence of pain on a ordinal numeric O-3 scale, along with any response.

Results: At the end of the study period, 291 correctly completed forms were collected. Based on a previous audit this would identify the incidence with a 95% confidence interval of & 3.7%. The age range of the patients was 1642 years, with 177 elective and 115 urgent or emergency procedures (CEPOD classification). Nausea was recorded in 91 cases (31.3%) and vomiting occurred in 36 cases (12.4%).


Despite its increasing popularity in the journals, only 50 patients (17%) received an opioid in the spinal injectate, fentanyl being the exclusive agent of choice. Pain was recorded in 20 cases (6.9%), 9 at grade one, 10 at grade two and 1 at grade three. Almost invariably an intravenous opioid was given to alleviate the pain, either fentanyl or alfentanil. In only 4 cases was nitrous oxide given, and in only one was it considered sufficient. In a further 8 cases (2.7%) a short-acting opioid analgesic was given although no pain was recorded. In total, 28 cases (9.6%) required supplementary analgesia. Analysis of the cases involved showed that analgesia was required despite an otherwise acceptable block as tested at the beginning of the case (in 27 of the cases T6 or above), and injectate volumes of 2.7 ml or greater in 25 cases.

Introduction: Addition of morphine to intrathecal bupivacaine provides excellent pain relief after caesarean section but increases nausea, vomiting and pruritus. Intrathecal diamorphine is reported to produce less severe side effects,’ but analgesia of shorter duration possibly because relatively smaller doses have been used.2 This study aimed to compare doses of intrathecal morphine and diamorphine that provide similar postoperative analgesia3 and examine the incidence and severity of side effects.

Conclusion: The high rate of recorded pain, and even higher rate of analgesic requirements during the procedure are significant. The implications lie in our communication skills, and are both clinical and medico-legal. We must better explain that some degree of discomfort is commonly experienced, and that this is not evidence of imminent block failure or any other imagined catastrophe. Also we must teach ourselves to cope quickly and efficiently with the inevitable event of pain, and teach other obstetric staff that under spinal anaesthesia the patient will not necessarily ‘feel absolutely nothing’.

Methods: Following ethics committee approval, 60 women presenting for elective caesarean section were randomised, in a double blind manner, to receive 2.5 ml of 0.5% hyperbaric bupivacaine and 12.5 ug fentanyl intrathecally with either 0.1 mg of morphine (group M) or 0.25 mg of diamorphine (group D). At the end of surgery, diclofenac 100 mg was given rectally and an intravenous morphine PCA attached. Severity of pain at rest and movement using a verbal numerical scale (O-10) was performed at 2, 4, 8 and 24 hours. At each time interval the incidence and severity of pruritus, nausea and drowsiness, the number of vomiting episodes, cumulative morphine use and oral analgesia requirement were noted. Overall satisfaction with postoperative analgesia was recorded at 24 hours.

REFERENCE

1. Riley E T, Cohen S E, Macario A, Desai J B, Ratner E F. Spinal versus epidural anesthesia for cesarean section: comparison of time efficiency, costs, charges and complications. Anesth Analg 1995; 80: 709-712.

5. A comparison of intrathecal bupivacaine-fentanyl- morphine with bupivacaine-fentanyl-diamorphine for post caesarean section pain relief

Results: There were no significant differences in speed of onset of block, block height or hypotension. No patient reported intraoperative pain. Apgar scores and umbilical blood gas analysis were similar. There were no significant differences in time to first PCA demand. Three women in group M and 2 in group D did not use their PCA. Morphine consumption and oral analgesia use in each time period, and total morphine use were similar (table). The incidence of nausea was similar but the number of vomiting episodes greater in group M although this did not reach statistical significance.

K Barkshire, R Russell, J Burry, M Popat Conclusion: In the doses used, we have not Nufjeld Department of Anaesthetics, demonstrated a difference in pain relief between John Radcliffe Hospital, Oxford, UK the groups. The severity of vomiting was greater

Table Use of PCA and incidence of side-effects.

Time of first PCA demand Total morphine used Post op nausea Post op vomiting Post op vomiting episodes Post op pruritus Post op drowsiness

*median and range

Group M (n = 30)

240 mins (1355974 mins)* 24 mg (&60 mg)*

n = 18 (60%) n = 11 (37%)

n = 49 n = 26 (87%) n = 16 (53%)

Group D (n = 30)

249 mins (1133788 mins)* 23 mg (O-l 16 mg)*

n = 20 (67%) n = 8 (27%)

n = 23 n = 28 (93%) n = 15 (50%)


after morphine. Intrathecal diamorphine is a suitable alternative to morphine for post caesarean section analgesia.

REFERENCES

Husaini SW, Russell IF. Intrathecal diamorphine compared with morphine for postoperative analgesia after caesarean section under spinal anaesthesia. Br J Anaesth 1998; 81: 1355139. Kelly MC, Carabine U, Mirakhur R. lntrathecal diamorphine for analgesia after caesarean section. Anaesthesia 1998; 53: 231-231. Roulson C, Chan A, Albin M, Carli F. Intrathecal morphine or diamorphine for Caesarean section? Preliminary findings. International Journal of Obstetric Anesthesia 1994; 3: 18 1.

6. Awake fibreoptic intubation skills in obstetric patients: A survey of anaesthetists in the Oxford Region

M.T. Popat,* M. Srivastavat, R. Russell* *Nuffield Department of Anaesthetics, John Radcliffe Hospital, Oxford OX3 9DU fRoya1 Berkshire Hospital, London Road, Reading RGl SAN, UK

Introduction: The majority of parturients with a known difficult airway presenting for caesarean section are successfully managed with regional anaesthesia. However, if regional anaesthesia is contraindicated or unsuccessful, then securing the airway by awake fibreoptic intubation (AFI) is a safe and reliable technique.’ This survey was conducted to determine the skills and practice of AFI amongst obstetric anaesthetists and to compare them with consultant anaesthetists with an interest in difficult airway management and specialist registrars in the final year of training.

Methods: A postal questionnaire was sent to 83 anaesthetists, 42 consultant obstetric anaesthetists (group 0), 21 consultant anaesthetists with an interest in difficult airway management (group D) and 20 specialist registrars (group S). The questionnaire was divided into two parts. The first part included a case scenario of a parturient with a known difficult airway presenting for elective caesarean section. Respondents were asked how they would anaesthetise this patient if regional block was contraindicated. If they chose AFI, they were asked to complete the second part which was designed to assess their practice of fibreoptic intubation in non-obstetric patients.

Results: We received 82 (98.8%) completed replies. 75/82 anaesthetists (91.5%) chose to secure the airway by awake intubation in the given scenario, 74 of these

+ 30 $ 25

Group 0 Group D Group S

Anaesthetists group

Figure Confidence in performing AFI in obstetric patients.

choosing AFI. Only 6 of these 74 anaesthetists had previously performed AFI in an obstetric patient. In group 0 only 12131 anaesthetists (38%) were confident to perform AFI in an obstetric patient compared to 13/18 in group D (72%) and 12/19 in group S (63%) (Fig). Overall 84% (group O-88%) of respondents stated that consultant obstetric anaesthetists should be experienced in performing AFI. If more than 3 AFUmonth is regarded as ‘regular’ practice, only 1 anaesthetist in the survey met this standard.

Conclusion: Although AFI skills are highly desirable in consultant obstetric anaesthetists, the majority in this survey would not be confident in performing this technique in a parturient with a known difficult airway. More AFI practice and training is required in non-obstetric patients to gain this confidence.

REFERENCE

1. Edwards R M. Fibreoptic intubation: A solution to failed intubation in the parturient? Anaesth Intensive Care 1994; 22: 718-719.

7. Paraesthesiae and nerve root damage following combined spinal epidural and spinal anaesthesia.

John Holloway*, Paul Seedt, Felicity Reynolds*, Geraldine O’Sullivan* *Departments of Anaesthesia and fPublic Health Medicine, UMDS and Guy’s and St Thomas’ Hospitals, London SE1 7EH, UK

Introduction: Since the introduction of combined spinal-epidural (CSE) anaesthesia and atraumatic needles, anecdotal reports have suggested an increasing frequency of paraesthesiae either during or after anaesthesia.’ As a first step to explore the question, we conducted a postal survey to see whether there was any indication that such symptoms might be increased with CSE and/or atraumatic needles in parturients.


Table The numbers of problems reported annually with each technique. Denominators are the approximate numbers of procedures conducted annually.

CSE Spinal

Whitacre Rate %I (Cl) Sprotte Rate% (CI) Both needles Rate% (CI)

13/10700 1.21 (0.57 to 2.58) 111554 0.64 (0.10 to 4.13) 14112254 1.14 (0.58 to 2.26)

H/17560 0.87 (0.49 to1.56) 18/12138 1.44 (0.72 to 2.89) 33129698 1.11 (0.69 to 1.76)

Total

28128260 1.00 (0.64 to 1.57) 19113692 1.35 (0.69 to 2.64) 47141952 1.12 (0.76 to 1.65)

Method: A questionnaire was sent to an anaesthetist at each of the 259 obstetric units in the UK about the use the different needles and techniques, the numbers conducted and whether neurological sequelae had been encountered, with details if available. Those reporting problems were questioned by telephone about the time scale. Data were analysed using logistic regression with robust standard errors.

Results: The response rate was 85.7%, with 94 units using single shot spinals (SSS) only, 8 CSE only and 120 using both. The majority used Whitacre or Sprotte needles with Quincke used in only 18 units (insufficient for statistical analysis). Minor neurological problems only were reported with an overall incidence of 1.12 per thousand (Table 1). Logistic regression demonstrated no significant difference between needles or techniques.

Discussion: These data, albeit approximate, do not suggest a significant difference in complication rate between CSE and SSS. There is a suggestion that Sprotte needles are to be preferred for CSE and Whitacre for SSS but this is influenced by the practice and performance of individual centres.

REFERENCE

1. Turner MA, Reifenberg NA. Combined spinal epidural anaesthesia: The single space double barrel technique. International Journal of Obstetric Anesthesia 1995; 4: 158-160.

8. Evaluation of sacral block during spinal anaesthesia for caesarean section

M.C. Nixon, H. Bromhead, J. Eldridge Department of Anaesthesia, St. Mary’s Hospital, Portsmouth, Hampshire

Introduction: Bourne et al. stated ‘... it is clinically recognized that spinal anaesthesia guarantees complete sensory loss below the most cephalad level.” However, Russell reported that over 90% of patients undergoing caesarean section with spinal anaesthesia retained touch sensation at Sl .2 This study was

designed to assess formally whether sacral sparing occurs and if so, whether patient comfort is affected.

Methods: After Ethics Committee approval and informed consent, 35 patients undergoing elective caesarean section were recruited. Spinal anaesthesia was performed in the left lateral position, using 2.5 ml 0.5% heavy bupivacaine with 25 l.tg fentanyl. Sensory block was assessed in dermatomes L5-S3 every 5 min until surgery started and again at the end of surgery, using 3 modalities: light touch (standardised 1 g stimulus), cold and pinprick. We assessed adequacy of pain relief during caesarean section using a visual analogue score (VAS).

Results: The median height of block at the start of surgery was T4 (light touch), T2 (cold) and T3 (pinprick). Sacral sparing was observed 5 and 10 min after injection (Fig). By the end of the procedure, only three patients still had unblocked sacral segments. The VAS was zero (no discomfort) for all patients except one, who had sacral sparing at Sl and, despite a cephalad spread to T3, experienced significant pain necessitating conversion to general anaesthesia.

UNBLOCKED SEGMENTS at 5 &IO MINUTES: (35 patients) 14 12 10 8 6 4 2 0

L5 Sl s2 s3 L5 “dg;; 53 L5 si sa s3 L5 Sl s2 s3 Left Left -5 mnutes- - 10 mlnufes- Right

Figure Unblocked segments at 5 and 10 min

Conclusion: We have confirmed that sacral sparing occurs. In this study the incidence was 63% (22 patients) at 5 minutes and 23% (8 patients) at 10 minutes. Sacral sparing is seen predominantly at Sl and most sensitively detected by light touch. It diminishes rapidly and appears, in general, to have no


effect on the overall quality of block. However, given that one patient in our study with persistent sacral sparing experienced significant pain, it remains arguable whether sacral block should be routinely assessed before caesarean section with spinal anaesthesia.

REFERENCES

1.

2.

Bourne TM, deMelo AE, Bastianpillai BA, May AE. A survey of how British Obstetric Anaesthetists test regional anaesthesia before caesarean section. Anaesthesia 1997; 52: 901&903. Russell IF. Testing regional anaesthesia before caesarean section. Anaesthesia 1998; 53: 93-94.

9. Do women in labour understand risk information about epidural analgesia?

S.V. Rutter, J.R. Clay, W.E. Scott Milton Keynes General Hospital, Standing Way, Eaglestone MK6 5LD, UK

Introduction: Understanding risk information is important for patients who give consent before epidural analgesia in labour and anaesthetists who obtain it.‘,2

Methods: After Ethics Committee approval, a calendar month was randomly selected for a confidential postal survey of 215 women who delivered vaginally. The patients’ questionnaire addressed the sources of risk information and how well the parturients were aware of the risks of epidural analgesia in labour. We also analysed 23 confidential questionnaires sent to anaesthetists working in our department, assessing their satisfaction with the current state of ‘informed’ consent and their perception of what women should know when requesting epidural analgesia.

Results: 14 anaesthetists (61%) were dissatisfied with the current circumstances of obtaining informed consent. In decreasing order (Fig. 1) the anaesthetists’ priorities about risk information were: headache (lOO%), incomplete block (96%), hypotension, severe motor block and backache (52%), instrumental delivery (35%), neurological damage (30%) and prolonged labour (22%). 133 valid returns (61.8%) were received from parturients, of which 34 (26%) comprised the epidural (EPI) group and 99 (74%)

Figure Awareness of potential problems: anaesthetists vs patients in labour.

non-epidural (NEPI) group. Awareness of risks of epidural blocks in parturients is summarized in the figure.

In decreasing order the priorities about risk information in the EPI group were: backache (76%), severe motor block (71%) headache (68%) incomplete block (59%), instrumental delivery (56%) hypotension (50%) prolonged labour and neurological damage (44%). Awareness of these risks in the NEPI group was generally worse than in the EPI group.

Conclusions: Our survey highlights some problems related to ‘informed’ consent for epidural analgesia in labour. There is a discrepancy between anaesthetists’ perception of which risks women need to be aware of and women’s actual awareness. A possible solution to the problem is to make an up-to-date leaflet incorporating risk information about epidural analgesia available to women antenatally with an appropriate record in their notes that the leaflet was given. This policy is being implemented in our hospital.

REFERENCES

1. Robinson PN, Salmon P, Yentis SM. Maternal satisfaction (Review). IJOA 1998; 7: 32-37.

2. Scott W. Ethics in obstetric anaesthesia (Editorial). Anaesthesia 1996; 51: 717-718.


10. Epidural analgesia after caesarean section: comparison between patient controlled ropivacaine or ropivacainelfentanyl and cost comparison with bolus diamorphinelclonidine

N. Hall, D. Buggy*, J. Brown*, J. Williams, S. Coley University Department of Anaesthesia and Pain Management, Leicester University and the *Department of Obstetric Anaesthesia, Leicester General Hospital, Leicester, UK

Introduction: Analgesia after caesarean section must ideally facilitate early mobilisation. Epidural analgesia is an effective option, especially if opioids are used to obviate motor block. They may be administered as doctor-given boluses or patient-controlled epidural analgesia (PCEA).‘x2 Ropivacaine is a new amide local anaesthetic, which produces less motor block than an equal dose of bupivacaine.3 It may be used as a sole analgesic, but combination of bupivacaine with opioids such as fentanyl has improved patient satisfaction with labour analgesia.4 The efficacy and side-effects of ropivacaine combined with fentanyl for postoperative analgesia have not been reported.

Objective: (1) To compare analgesic efficacy, motor weakness and side-effects of PCEA using ropivacaine alone or in combination with fentanyl. (2) To compare the costs of PCEA with those of doctor-controlled bolus epidural analgesia using diamorphine and clonidine.

Methods: After Ethics Committee approval and informed consent, ASA I patients undergoing elective caesarean section under combined spinal-epidural anaesthesia (CSE) were randomly assigned into three groups: group CD (n=20) received epidural diamorphine 2 mg plus clonidine 7.5 ng in recovery and could request a further bolus after 6 h. Group R (n=23) received PCEA ropivacaine 0. lo!, bolus 5 mg, lockout 15 min, with 3 mg/h background infusion. Group RF (n=24) received PCEA ropivacaine 0.1% plus fentany12 pg/ml, at identical settings to group R. Patients and staff were blind to group randomisation in R and RF, but the CD group was open to enable cost deductions to be made. Pain at rest and on movement and patient satisfaction were compared on a 100 mm visual analogue scale (VAS) at 2, 4, 6, 8, 12 and 24 h, using repeated-measures ANOVA. Categorical data were evaluated by x2 analysis of contingency tables.

Results: Pain scores on movement were significantly lower in RF compared with R at 6, 8, 12 and 24 h, and were lower at rest at 6 and 12 h (PCO.05, each

comparison). Mean total analgesic consumption was 199L23 mg in R compared with 175+15 mg in RF (mea&SD, P~0.05). Incidence of motor weakness (Bromage grade 1 or more) was 48% (1 l/23) at 8 h in R compared with 12% (3/24) in RF (PcO.05). Incidence of nausea, pruritus and hypotension were not significantly different between the groups. Patient satisfaction (expressed as VAS, mean + SD) with postoperative analgesia was higher in RF compared with R (79f9 versus 56 k 12, PcO.05). Bolus therapy using CD gave relatively low pain scores, no motor block after 6 h and a high degree of patient satisfaction (VAS 88+11). Despite being relatively labour-intensive, bolus therapy was also associated with significantly lower costs than either PCEA technique (&8&l versus 528k2 versus &30&l, PcO.01, mea&SD).

Conclusions: These data suggest that PCEA with RF provides better analgesia, less motor weakness and better patient satisfaction than R alone after caesarean section. Epidural bolus therapy with CD may be more cost effective than either PCEA regimen and is also associated with high analgesia, satisfaction levels and no residual motor block after 6 h. Prospective, blind studies comparing this bolus regimen with PCEA are warranted.

REFERENCES

Rockemann MG, Seeling W, Duschek S, Reinelt H, Steffen P and Georgieff M. Epidural bolus clonidine/morphine versus epidural patient controlled bupivacaine/sufentanil: quality of postoperative analgesia and cost-identification analysis. Anesth Analg 1997; 85: 864869. Vercauteren MP, Vandeput DM, Meert TF, and Adriaensen HA. Patient controlled epidural analgesia with sufentanil following Caesarean section: the effect of adrenaline and clonidine admixture. Anaesthesia 1994; 49: 767-771. McClure JH. Ropivacaine. Br J Anaesth 1996; 76: 300-307. Collis RE, Davies DWL, Aveling W. Randomised comparison of combined spinal-epidural and standard epidural analgesia in labour. Lancet 1995; 345: 1413-1416.

11. General anaesthesia for emergency caesarean section: could regional anaesthesia have been used?

J. Shah, J. Wynroe, A. Gornall, J. Klein, T.M. Bourne, A.E. May Leicester Royal Infirmary, Women’s Hospital, Departments of Anaesthesia & Obstetrics, Leicester LEl 5 WW UK

Introduction: Complications of general anaesthesia for caesarean section remain a leading cause of anaesthesia related maternal mortality.1,2 Morgan et al. showed that emergency caesarean section could be anticipated in 87% of women3 When caesarean


section is indicated because of fetal distress general anaesthesia is often used as the fastest anaesthetic technique. The term fetal distress is imprecise, non specific, has low predictive value and is often associated with the delivery of an infant who is in good condition4 This review was undertaken to find the reason general anaesthesia was used for emergency caesarean section.

Method: We reviewed the medical records of all women who underwent general anaesthesia for emergency caesarean section from January-December 1997. We collected the following data: (1) indication for caesarean section, (2) indication for general anaesthesia, (3) time of the day, (4) time from decision to delivery, (5) seniority of anaesthetist and obstetrician, (6) assessment of CTG and (7) neonatal assessment: umbilical artery pH and Apgar score.

Results: 114 emergency caesarean section were done under general anaesthesia. Common reasons for emergency caesarean section were fetal distress (38%) and failure to progress (21%). Common reasons for general anaesthesia for emergency caesarean section were perceived lack of time (64%) and inadequate regional block (26%). For all emergency caesarean sections under general anaesthesia, 72% were done between 17:Ol and 08:29. Time from decision to delivery was >31 min in 41%. Emergency caesarean sections for fetal distress under general anaesthesia: 86% were done between 17:01- 08:29 hours. Time from decision to delivery was >31 min in 28%. The umbilical artery pH was >7.15 in 85%. Apgar Score was >7 in 88%. Bradycardia was found in 44% of CTGs. A consultant anaesthetist was present in 12% and a consultant obstetrician in 0% of emergency caesarean section done under general anaesthesia.

Conclusions: Many caesarean sections for fetal distress under general anaesthesia could, in retrospect, have been delayed to allow regional anaesthesia. More than 31 min is sufficient time to establish an adequate regional block. Early communication in a busy unit might help in resiting an epidural block and decrease the need for general anaesthesia. Suboptimal blocks might be expected less frequently with more experienced anaesthetists. More senior medical involvement may help to increase the use of regional anaesthesia.

REFERENCES

1. Hawkins J L, Koonin L M, Palmer S K, Gibbs C. Anesthesia related deaths during obstetric delivery in the United States, 1979-1990. Anesthesiology 1997; 86: 277-284.

2. Report on Confidential Enquires into Maternal Deaths in the United Kingdom 1991-1993, London: HMSO, 1996.

3. Morgan B M, V Magni, Goroszenuik T. Anaesthesia for emergency caesarean section. Br J Obstet Gynaecol 1990; 97: 420424.

4. Chestnut D H. Anesthesia for fetal distress. In Obstetric Anesthesia, Principles and Practice 1994, pp 487-499.

12. Post-dural puncture headache in obstetric patients - experience from a West African teaching hospital

O.O., Nafiu E.O. Elegbe Department of Anaesthesia, Korle Bu Teaching Hospital, Accra, Ghana

Introduction: Post dural puncture headache (PDPH) is an unfortunate complication of spinal anaesthesia. While there are fairly conclusive data about the incidence and aetiology of PDPH in developed countries,‘.* there is a dearth of data from developing countries. We describe the frequency and severity of PDPH in parturients undergoing caesarean section under spinal anaesthesia in a West African teaching hospital.

Methods: Data were collected prospectively on 96 ASA I-II consenting mothers who had spinal anaesthesia for caesarean section. All blocks were performed by one investigator while the second investigator conducted the review and management of patients with PDPH. All patients were pre-loaded with 500-1000 ml Ringers lactate and dural puncture was performed using 22, 25 or 26 gauge Quincke needles. All needles were inserted with the bevel oriented laterally. Patients were followed up for 3 days postoperatively. Those with PDPH were assessed using a Visual Analogue Scale (VAS).

Results: A total of 96 parturients were studied. There were 58 (60.4%) emergency and 38 (39.6%) elective cases. Dural puncture was performed with a 25 gauge needle in 46 patients (47%), a 26 gauge needle in 38 patients (39.6%) and a 22 gauge needle in 12 patients (12.5%). PDPH occurred in 8 patients (8.3%). Fifty percent of the PDPH occurred in patients in whom 22 gauge needles were used. Most patients graded their headache as mild, while 3 patients had moderate headaches. All were managed with analgesics and liberal fluids. No patient needed an epidural blood patch.

Conclusion: The incidence of PDPH in our patients is similar to that usually reported from developed countries before the widespread use of pencil point needles.* Unfortunately, non-cutting needles are too expensive for most health services in developing countries. We believe that the relatively low incidence of PDPH in our patients may be related to lateral


bevel orientation of the spinal needles. We are however aware that these rates could be improved with the use of small calibre, non-cutting needles.

REFERENCES

1. Gerard K W, Fagraeus L. Post spinal headache. Seminars in Anaesthesiology 1990; 9: 68874.

2. Shuttle L E, Valentine S J, Wee M Y K, Page R J, Prosser A, Thomas T A: Spinal anaesthesia for caesarean section; comparison of 22 g and 25 g Whitacre needles with 26 g Quincke needles. Br J Anaesth 1992; 69: 5899594.

13. A paradoxical change in obstetric outcome following the introduction of low dose epidurals for obstetric analgesia

B.J. Norman, M. Hasan Northwick Park Hospital, Harrow, Middlesex, HAI 3 UJ UK

Introduction: Previous studies have shown that low dose epidurals for analgesia in labour are associated with a lower obstetric intervention rate than high dose epidurals.‘s2 This retrospective study analyses the change in obstetric outcome with the introduction of low dose epidurals at our hospital.

Methods: Parturients were classified as receiving high dose epidural analgesia if the dose following the initial epidural dose was 10 ml of 0.25% bupivacaine. If the dose following the initial epidural dose was 10 ml of 0.1% or 0.125% bupivacaine with 20 pg of fentanyl, this was classified as a low dose epidural. The choice between a high dose and a low dose epidural was dependent on the personal preference of the anaesthetist. The number of patients receiving each type of epidural, and their mode of delivery, was recorded between 1994 and 1997.

Results: Data were available for 2278 primiparous and 834 multiparous women. The percentage of patients receiving low dose epidurals increased steadily from 34.0% in 1994 to 98.0% in 1997. The Figure shows the

Primiparous Multiparous

Figure Mode of delivery in primiparous and multiparous patients (%) who had had a high dose or low dose epidural.

types of delivery for primiparous and multiparous women receiving each type of epidural. Findings were similar when data for each year were analysed individually. For primiparous women obstetric outcome was similar in the two groups. However, in multiparous women there was a significant increase in instrumental and caesarean deliveries for those who had had low dose epidurals (P = 0.019, x2 test).

Conclusion: The observed association between low dose epidurals and a decreased chance of spontaneous delivery in multiparous women is not necessarily causal, and should be interpreted with caution. It is not consistent with previous prospective and retrospective studies. 1,2 Nonetheless we present these data in case other units have found a similar association.

REFERENCES

1. Olofsson CH, Ekblom A, Ekman-Ordeberg G, Irestedt L. Obstetric outcome following epidural analgesia with bupivacaine-adrenaline 0.25% or bupivacaine 0.125% with sufentanil - a prospective randomized controlled study in 1000 parturients. Acta Anaesthesiol Stand 1998; 42: 284292.

2. Norman B, Jenkins G. Change in rate of spontaneous vaginal delivery following introduction of low dose epidurals (abstract). International Journal of Obstetric Anesthesia 1997; 6: 211-212.

14. Haematological referrals from obstetric patients

T Isitt, R Fernando, A England The Royal Free Hospital, London NW3 2QG UK

Introduction: The Royal Free Hospital is a regional centre for haematology. The anaesthetic department received referrals for 30 women with haematological pathology delivering between January and October 1998. A consultant anaesthetist saw them antenatally and in the peripartum period. Data were collected and stored as part of an ongoing computerised audit of complicated obstetric patients. Significant morbidity is described where it occurred.

Findings: Five groups of patients were identified: hypocoagulable (5), hypercoagulable (9), platelet disorders (9), haemoglobinopathies (3) and previous deep vein thrombosis (4).

Hypocoagulable states: Haemophilia trait (l), Factor IX deficiency (2), Factor XI deficiency (2). Three had normal clotting factor levels. One received epidural analgesia for spontaneous vaginal delivery (SVD). Two had elective caesarean sections under combined spinal epidural anaesthesia (CSE) and one of these developed an extensive wound haematoma. Two had clotting factor levels below the normal range. One


required emergency caesarean section under general anaesthesia (GA) and received tranexamic acid postoperatively. The other had SVD, but required GA for retained placenta and suffered a 2 L postpartum haemorrhage requiring 3 units of blood and 3 units of fresh frozen plasma.

Hypercoagulable states: Protein C deficiency (3) Protein S deficiency (l), Factor V Leiden deficiency (6), Prothrombin III polymorphism (1). (1 had combined Protein C and Factor V deficiency; 1 had Factor V deficiency and Prothrombin III polymorphism). All received fragmin during the third trimester and two received aspirin 75 mg/day until 36 weeks. Six delivered vaginally, five with epidural analgesia. Three had elective caesarean section under CSE. Regional blocks were inserted between 6 and 24 h after the last dose of fragmin and no more was administered until after catheter removal.

Platelet disorders: Thrombocytopenia (6: 5 immune and 1 HIV-mediated), von Willebrands disease (3: 1 had both von Willebrands and platelet storage disease). Six had elective caesarean section (3 GA and 3 CSE, 2 of whom had a CSE with platelet counts ~90 x 109/L). Three had SVD and two received epidural analgesia. Three women with ITP received a 5-day course of Sandoglobulin in the third trimester for thrombocytopenia and 1 received corticosteroids at 26 weeks. Two required further Sandoglobulin postnatally. The patient with von Willebrands and platelet storage diseases received DDAVP and tranexamic acid postnatally.

Haemoglobinopathies: Beta thalassaemia major (2), homozygous haemoglobin S disease (1). All were delivered by caesarean section under regional blockade. The woman with sickle S disease suffered several antenatal crises requiring 2 exchange transfusions. One, with thalassaemia major, died a week postpartum from pre-existing cardiac disease.

Previous deep vein thromboses: Four patients, three delivered by elective caesarean section (one GA for inferior vena cava umbrella, two CSE), the other by SVD under epidural.

Conclusion: Problems were greatest in women who were not seen antenatally by an anaesthetist. Anaesthetic morbidity was uncommon in women who had management plans agreed in advance between the obstetric, haematology and anaesthetic consultants. These management plans were easily accessible to the anaesthetic trainees.

15. Performance of standard and reservoir Hudson masks in pregnant and non-pregnant subjects

E.A.J. Morris, A.J. Smith, S.M. Kinsella Department of Anaesthesia, St Michael’s Hospital, Bristol BS2 8EG, UK

Introduction: The Hudson-style mask is used to provide low levels of oxygen therapy (average inspired oxygen concentration [F,O,] of 0.3-0.4) and the Hudson non-rebreathing mask with reservoir bag for maximum oxygen therapy (nominal F,O, 1.0) in critically ill patients and as part of fetal resuscitation. Fetal oxygenation is maximal with maternal F,O, of 1.0.’ Neither of these devices has been evaluated in pregnant women.

Method: Non-pregnant subjects breathed from a standard mask or a reservoir mask, with four oxygen flows from 4 to 15 L/min. Gases were sampled continuously through a tube secured beneath the subject’s nostril and insulated from the incoming gas flow. After equilibration expired oxygen fraction [FEOZ] was measured using a Hewlett Packard monitor M1025B. Term pregnant subjects were similarly studied but at only two oxygen flows, 4 and 15 L/min.

Results: Seven subjects have been studied in each group. In normal subjects, increasing oxygen flow rate increased F,O,. At all oxygen flows, mean F,O, was significantly (P<O.Ol) higher when using the reservoir mask than the standard mask. Similar findings applied to the pregnant subjects, but all mean F,O, values were lower by 2-9% than in the non-pregnant subjects under corresponding conditions (Table).

Table Mean F,O, values

Non-pregnant Pregnant

Standard Reservoir 4 Urnin 15 Urnin 4 Urnin 15 Umin

0.32 0.48 0.43 0.7 0.3 0.41 0.34 0.65

Discussion: Assuming average F,O, is 5% higher than F,O,, we conclude that the standard mask is adequate for low oxygen therapy. For maximum oxygen administration however, the reservoir mask did not perform according to the manufacturer’s specification (F,O, of 1 .O), giving a mean F,O, of only 0.7 in non- pregnant and 0.65 in pregnant women. If F,O, is lower in pregnancy because of increased tidal volume


or peak inspiratory flow rate, we suspect that mask performance may be even worse during labour. We are hoping to clarify the reasons for this under- performance.

REFERENCES

1. Ramanathan S, Gandhi S, Arismendy J, Chalon J, Turndorf H. Oxygen transfer from mother to fetus during cesarean section under epidural anesthesia. Anesth Analg 1982; 61: 576581.

16. Comparison of two volume regimens for labour epidurals

M. Atkins, M. Dresner, J. Charlton Obstetric Anaesthesia, Leeds General Infirmary, Leeds, UK

Introduction: Two papers presented to the OAA in 1997 described our epidural regimen of the time.‘s2 This consisted of 0.1% bupivacaine with 2 pg/ml fentanyl given as a 20 ml loading dose, followed by an infusion of 12 ml/h and 20 ml top ups (20,12,20). Some delegates regarded these drug volumes as excessive. A regimen more typical of national practice with the drug cocktail mentioned is a loading dose of 15 ml, an infusion of 8 ml/h, and top ups of 10 ml (15,8,10), to which we converted soon after the meeting. We resolved to compare these two regimens by means of a detailed audit.

Methods: Epidural techniques are strictly standardised in our unit. Comprehensive demographics, procedural details, obstetric outcome, complications reports, midwife and patient assessments are recorded by our modification of the Wansbeck epidural audit program. The records are stored on an Access database, at present containing prospectively compiled data from 2500 epidurals. We identified all 20,12,20 and 15,8,10 epidurals and compared all relevant outcomes using the x2 test.

Results: There were no differences in demographics or complication rates between the groups. Other results are shown below (Table), including the midwife and

Table Outcome

l&8,10 regimen 20,12,20 regimen P value

Patient numbers 234 948 Normal deliveries 124 (53%) 501 (52.8%) ns. Forceps/ventouse 56 (23.9%) 214 (22.6%) n.s. Sections 54 (23.1%) 233 (24.6%) n.s. Minimal motor block 119 (50.9) 511 (53.9%) n.s. Midwife ‘excellent’ 87 (37.2%) 497 (52.4%) 0.001 Patient ‘excellent’ 164 (70.1%) 713 (75.2%) n.s. >3 top ups given 70 (29.9%) 133 (14.0%) 0.0012

patient overall assessment of the epidural’s performance. ‘Excellent’ is the best of a four point verbal scale.

Conclusion: Although the greater proportion of ‘excellent’ patient assessments for the 20,12,20 regimen did not reach statistical significance, the difference in midwife verdicts did. This could be explained partly by suspicion of a new protocol (a very real delivery suite phenomenon), but more likely by the increased number of top ups required with the 15,8,10 regimen. The 20,12,20 regimen is labour saving for the midwife without any penalties such as increased motor block or complications. We therefore conclude that our use of a relatively high volume regimen described in earlier studies is vindicated.

REFERENCES

1. Dresner M, Bamber J, Freeman J, Calow C. Combined spinal- epidural or epidural? A randomised comparison of two low dose epidural techniques. International Journal of Obstetric Anesthesia 1998; 7: 195.

2. Calow C, Dresner M, Bamber J, Freeman J. Does motor block influence satisfaction with epidural analgesia? International Journal of Obstetric Anesthesia 1998: 7: 1955196.

17. Epidural ropivacaine for continuous analgesia in labour: a dose-response study

D.A. Hughes, D.A. Hill Department of Anaesthesia, Ulster Hospital, Belfast, iV Ireland

Introduction: Published studies regarding ropivacaine infusions for labour analgesia have shown analgesic efficacy with 0.25% ropivacaine,’ and more recently with 0.2% solutions.2 However, both demonstrated a significant degree of motor blockade in the patients studied. This study investigated the use of ropivacaine at the concentrations currently used in obstetric anaesthesia.

Methods: We studied 49 parturients randomised to receive 0.2%, 0.1% or 0.05% ropivacaine infusions at 10 ml/h, with 0.2% top-ups on request if analgesia was inadequate. Motor blockade was assessed on the modified Bromage scale and quality of analgesia on a four point verbal rating scale (1 = no sensation, 4 = distressing pain/pressure). The hourly anaesthetic requirement, via infusion and top-ups, was calculated for each woman.

Results: Pain scores did not differ between groups. Hourly ropivacaine requirements did not differ significantly between the 0.1% and 0.05% groups, but both were significantly lower than the 0.2% group


Table Outcome

Hourly ropivacaine dose Grade 3 Perineal Group (mg) median (range) block (n) pain 0.2% (n = 18) 23.73 (18.431.4)* 4 7 (39%) 0.1% (n = 17) 15.71 (12.1-26.2) 2 5 (29%) 0.05% (n = 14) 16.16 (8.8-22.3) 0 8 (57%)

*P < 0.001

(P<O.OOl, P=O.OOl respectively). Fewer women in the 0.05% and 0.1% ropivacaine groups had grade 3 (modified Bromage) motor blockade compared to the 0.2% group, but this failed to reach statistical significance (Table).

Conclusion: We conclude that the concentration of ropivacaine infusion for continuous analgesia in labour can be reduced below 0.2% while maintaining equivalent efficacy and potentially further reducing motor blockade. The occurrence of perineal pain at delivery ranged from 39% in the 0.1% group to 57% in the 0.05% group. We suggest that analgesia may be further improved, without worsening motor block, by the addition of opioid to the infusions.

REFERENCES

1.

2.

Eddleston JM, Holland JJ, Griffen RP, Corbett A, Horsman EL, Reynolds F. A double blind comparison of 0.25% ropivacaine and 0.25% bupivacaine for extradural analgesia in labour. Br J Anaesth 1996; 76: 66-71. Benhamou D, Hamza J, Eledjam JJ et al. Continuous extradural infusion of ropivacaine 2 mg/ml for pain relief during labour. Br J Anaesth 1997; 78: 7488750.

18. Entonox equipment: a potential source of cross infection?

R.J. Chilvers, M. Weisz Department of Anaesthetics, Peterborough District Hospital, Peterborough, UK

Introduction: Entonox is widely used throughout the UK as an inhalational analgesic during labour. Over the last few years concerns regarding potential sources of infection have led to the introduction of microbiological filters on anaesthetic breathing circuits. The aim of this study was to survey current practice regarding the cleansing of, and the use of filters with, Entonox apparatus.

Methods: A survey was carried out using a standardised questionnaire enquiring about the practices relating to the routine care of Entonox apparatus with emphasis on the use of filters and cleaning procedures. All hospitals with obstetric units within the Anglia and Oxford Region were contacted; the most senior midwife available was interviewed.

Results: Twenty hospitals in the Anglia and Oxford Region were identified. The response rate was 100%. Entonox was used in all the units. Midwives and Health Care Assistants were responsible for cleaning the equipment after use. Various methods were used: masks were cleaned with soap and water only (9/20), soap and water followed by alcohol spray (l/20), soaked in sterilising solution (3/20), wiped with alcohol (2/20), washed with chlorhexidine (l/20), washed in water only (l/20) or sent to CSSD (2120). One hospital reported that masks were never used. Mouthpieces were single use and disposable (8/20), sent to CSSD (6/20), washed and then soaked in sterilising solution (4/20) or washed in soap and water (2/20).

Filters were used in only two hospitals; these were changed after every patient and were either disposable or sent for sterilisation. A third hospital had filters introduced and subsequently withdrawn. In the majority of hospitals the demand valve was not cleaned between patients (18/20) and surface wiped in two hospitals. The corrugated tubing was neither cleaned nor replaced after use at any hospital,

When questioned regarding the use and cleaning of Entonox apparatus following use with known ‘high risk’ patients, no additional measures were taken in three hospitals; in the other hospitals all equipment was sent to CSSD Q/20), cleaned more thoroughly (l/20), discarded (2/20), cleaned with soap and water (l/20), tubing changed or discarded (2/20), or the mask and mouthpieces soaked in Milton@ (l/20). Two respondents were unsure but would contact their infection control team; two hospitals reported they had no ‘high risk’ patients.

Conclusions: There is no general consensus regarding cleaning of Entonox equipment in labour wards in the Anglia and Oxford Region. In contrast to anaesthetic machines where filters are recommended’ and in widespread use, only two hospitals were using microbiological filters on Entonox equipment. We consider all patients to be potentially ‘high risk’ as a source of infection and all patients should be protected from cross infection. The recommendation that a microbiological filter should be placed between the patient and the breathing system should be extended to Entonox apparatus.

REFERENCE

1. The Association of Anaesthetists of Great Britain and Ireland. A report received by the council of the Association of Anaesthetists on blood borne viruses and anaesthesia, January 1996.


19. A comparison of glucose 8 mg/ml or glucose 80 mg/ml with hupivacaine 5 mglml for spinal anaesthesia for caesarean section

C. Connolly, J.A.W. Wildsmith, G. McLeod Department of Anaesthesia, Ninewells Hospital and Medical School, Dundee DDI 9SX UK

Objectives: Studies in non-pregnant subjects have shown intrathecal bupivacaine with 8 mg/ml glucose to be as efficacious for spinal anaesthesia as the standard hyperbaric 80 mg/ml preparation (density 1.0230 at 37C”C).‘m3 As the density of CSF in the pregnant patient reaches a nadir at term (1.0003 f 0.0004), bupivacaine 5 mg/ml with glucose 8 mg/ml remains slightly hyperbaric. The aim of this study, therefore, was to compare the onset, spread, quality and duration of spinal anaesthesia for caesarean section with bupivacaine 5 mg/ml in glucose 8 mg/ml or glucose 80 mg/ml and to assess the cardiovascular stability with each solution.

Methods: Forty women (aged 1840 years) undergoing elective caesarean section gave informed consent for this study which was approved by the local ethics committee. Patients were placed in the right lateral position with a pillow under the dependant shoulder. Under aseptic conditions, a 25 gauge Whitacre needle was introduced at L314 with the needle port facing cephalad. The study solution (2.5 ml) was injected at 1 ml/5 s and the end of injection defined as time zero. The study solution in group A was bupivacaine 5 mg/ml with glucose 8 mg/ml and in group B bupivacaine 5 mg/ml with glucose 80 mg/ml. Patients were immediately placed in the left wedged position. Sensory block was determined using the blunt end of a 27 gauge dental needle at 2, 5, 10, 15,20,25, 30 min after injection and every 15 min for 2 h thereafter. The extent of block was measured on both sides and an average taken if there was a difference. Blood pressure was measured pre-op, every 2 min for 10 min and every 5 min for 2 h. Hypotension (defined as a systolic blood pressure >20% below the pre-operative figure or symptoms related to poor perfusion such as nausea or dizziness) was treated with 6 mg ephedrine intravenously as required. The spinal anaesthetic was supplemented with increments of either alfentanil or morphine as required. Postoperatively, all patients received diclofenac 100 mg per rectum. The time to first morphine requirement was noted and the first bolus was given intravenously by the investigator.

Results: No demographic differences existed between the groups. Speed of onset of sensory block, time to

maximum sensory block and median maximum block height were the same in the two groups. Four patients in group A and two in group B had sensory block to cervical dermatomes. Five patients in group A and eight in group B required intra-operative opioid supplementation. Patient satisfaction scores were equivalent in the two groups. There was no difference in two segment regression, regression to TlO or times to first request for morphine. No differences existed between the groups with regard to cardiovascular parameters or ephedrine requirement.

Conclusion: Despite a lo-fold difference in glucose concentrations, only minor differences existed between the two solutions. This would suggest that baricity is of relatively little importance in spinal anaesthesia at term.

ACKNOWLEDGEMENT

Dr C. Connolly was supported by Astra Pain Control, Sweden.

REFERENCES

1. Bannister .I, McClure JH, Wildsmith JA. Effect of glucose concentration on the intrathecal spread of 0.5% bupivacaine. Br J Anaesth 1990; 64: 2322234.

2. Sanderson P, Read J, Littlewood DG, McKeown D, Wildsmith JA. Interaction between baricity (glucose concentration) and other factors influencing intrathecal drug spread. Br J Anaesth 1994; 13: 744146.

3. Richardson MG, Wissler RN. Density of lumbar cerebrospinal fluid in pregnant and non pregnant humans. Anesthesiology 1996; 85: 326330.

20. Does intrathecal fentanyl provide cardiostability at caesarean section?

J.Y. Bigeon, R.P.R. Smith, R. Wadsworth, A. Vohra St Mary’s Hospital, Manchester, UK

Introduction: Spinal block is considered by many authorities to be the ideal anaesthetic for elective caesarean delivery’ and the majority of sections are now performed under regional anaesthesia. Indirect evidence from the Confidential Enquiries into Maternal Deaths showed that avoiding general anaesthesia in pregnancy contributed to an improved outcome for the mother.* However, hypotension may occur following the profound sympathetic blockade associated with spinal anaesthesia. The study aimed to see whether this could be avoided by reducing the intrathecal dose of local anaesthetic by the addition of fentanyl. Grant et a1.3 showed that intrathecal fentanyl 25 p.g in non-labouring pregnant women did not produce clinically important haemodynamic change. We examined the cardiovascular effects of this dose of intrathecal fentanyl when combined with 12.5 mg of 0.5% heavy bupivacaine for use in spinal anaesthesia for caesarean section.


Methods: Following ethics approval and informed consent 20 patients were randomized and blinded into two groups. Control group (CG) bupivacaine 15 mg only and fentanyl group (FG) bupivacaine 12.5 mg + 25 ug fentanyl. Mean arterial pressure (MAP) and heat rate (HR) were measured using automated oscillotonometry (Datex). Continuous cardiac index (CI) was measured by bioimpedance (BoMed Inc Irving). Total vascular resistance index (TVRI) was calculated. Ephedrine (3 mg) was given for overt hypotension (MAP ~60 mmHg) or on the basis of clinical assessment of the patient. Measurements were recorded at 1-min intervals for 30 min and analysed using Mann-Whitney and the t-tests.

Table

MAP CI TVRI HR mmHg L.minP.m~2 dyne.s.cm~sm~2 bpm

Control Group Baseline 99 5.1 1624 91 Mean ranges (min-max) 68-108 3.9-1.2 1077-2122 766110 Fentanyl Group Baseline 107 5.8 1659 107 Mean ranges (min-max) 58-104 3.1-1.6 1820-2205 69-120

Interventions Ephedrine mg mean (SD)

Control Group 6110 1.2 (8.5) Fentanyl Group 9110 17 (10.7) P = 0.034

Results: There were no differences between the two groups in knife to skin time (KTS) or KTS to delivery time. There were no significant differences between the two groups in block heights or haemodynamic parameters MAP, CI, TVRI or HR. Ephedrine interventions were greater in FG. Total ephedrine requirements were significantly greater in FG.

Conclusions: It was not surprising that there were no significant differences in the haemodynamic parameters between the two groups as the anaesthetist intervenes to maintain stability. However, we cannot recommend the addition of fentanyl to a reduced dose of local anaesthetic to maintain cardiostability because more ephedrine was required in these patients.

REFERENCES

1. SA Lussos, F Datta. Anesthesia for cesarean delivery, part 1, General considerations and spinal anesthesia. International Journal of Obstetric Anesthesia. 1992; 1: 79-91.

2. Report on Confidential Enquiries into Maternal Deaths in the United Kingdom 1991-1993. Her Majesty’s Stationery Office. London, 1996.

3. Grant GJ, Susser L, Cascio M, Moses M, Zakowski MI. Hemodynamic effects of intrathecal fentanyl in non-laboring term parturients. Journal of Clinical Anesthesia. 1996; 8: 999103.

21. Spinal anaesthesia following failed epidural anaesthesia for instrumental or operative delivery

A. Simpson, D. Smith, E. McGrady Glasgow Royal Maternity Hospital, Glasgow, UK

Introduction: The requirement for operative or instrumental delivery in the event of inadequate epidural block is not an uncommon problem in obstetric anaesthetic practice. The options are then general anaesthesia, the complications of which are well documented in the obstetric population, or spinal anaesthesia. Spinal anaesthesia following failed epidural anaesthesia is perceived as having a greater risk of high or total spinal. There have been several reports in the recent literature of high or total spinal anaesthesia following failed epidural block. In addition there is no consensus as to the dose of spinal bupivacaine to use in these circumstances.‘.* Should epidural anaesthesia be inadequate for operative or instrumental delivery, it is the practice in our hospital to remove the epidural catheter and to perform a spinal anaesthetic.

Method: We therefore decided to perform a three-year retrospective chart review of patients in our hospital to determine the incidence of high spinal following failed epidural block and to determine the dosage of bupivacaine used by our anaesthetic staff in these circumstances. During the period or review (1994-96) the average number of deliveries at Glasgow Royal Maternity Hospital (GRMH) was 4800 per year, the epidural rate was approximately 30%, the average emergency caesarean section rate was 570 per year, of which 44% were performed under epidural anaesthesia.

Results: There were 72 patients who received spinal anaesthesia following inadequate epidural block. Eight patients received their spinal after delivery (six manual removal of placenta, one repair 3rd degree tear, one no reason given). Of the remaining 64 patients, 48 had emergency caesarean section and 16 had instrumental delivery (all were prepared for caesarean section). None of our patients had a high or total spinal where they experienced respiratory difficulty or required respiratory support. The highest block recorded was C6 bilateral, the patient was at term and received 11.25 mg of heavy bupivacaine for trial of forceps and proceeded to emergency caesarean section. Her epidural had been adequate for labour analgesia but she had inadequate sacral block for trial of forceps. At no point did she experience respiratory difficulty and she required only 6 mg of ephedrine. 57.8% of our 64 patients received 12.5 mg of heavy


bupivacaine, 37.5% received a smaller dose (range 7.5-l 1.25 mg) and 4.7% received a larger dose (range 15-17.5 mg).

Conclusion: None of our patients who received spinal anaesthesia following failed epidural block experienced a high or total spinal. 57.8% received a standard spinal dose of 12.5 mg of heavy bupivacaine.

REFERENCES

1. Stone P A, Thorburn J, Lamb K S R. Complications of spinal anaesthesia following epidural block for caesarean section. Br J Anaesth 1989; 62: 335-337.

2. Furst S R, Reisner L S. Risk of high spinal anesthesia following failed epidural block for cesarean delivery. Journal of Clinical Anesthesia 1995; 7: 71-74.

22. Ultrasound controlled peridural anaesthesia in obstetrics - a prospective controlled pilot study

Th. Grau, R. Conradi, E. Martin University of Heidelberg, Germany

Introduction: Conventional puncture of the lumbal epidural space is sometimes difficult in pregnancy: there is a problem of the difficult puncture and a problem of the perforation of the dura. The main reasons for these problems can be seen in the variation of puncture depth and the anatomical variety in the lumbar region of pregnant patients. Primary aims of this study were to find a qualitative good method for the detection of the lumbar epidural space and to use ultrasound for epidural anaesthesia.

Method: After approval of the local ethics committee and after written consent from the patients, ultrasound investigation of the lumbar region was made before the puncture. Ultrasound was performed with an Kretz SONOACE 6000 and a 5.0 MHZ slight curved ultrasound sensor. Ultrasound was taken in two plains: vertical and horizontal to get three dimensional information on bone and ligament structures. In a prospective randomised study design 60 control epidural anesthesias and 60 ultrasound- controlled epidural anaesthesias for pain management under delivery were performed. We used the loss of resistance method in both groups.

Results: The two groups were similar, regarding demographic data like age (29.8/30.1 years), weight (79.1 kg/79,7 kg), height (165 cm/166 cm), gestation week, (38/38), ASA classification [2.0/2.1] and risk factors. We found puncture depth between 38 mm and 85 mm and vertical puncture angles between 5 and 40”. The mean number of attempts for successful puncture was 1.29+0,61 in the ultrasound and 2. lfl. 1

in the control group. The mean number of needed puncture plains was 1.14 + 0.4 in the ultrasound group and 1.4kO.62 in the control. In the ultrasound group we had a mean measured depth of 53.2k7.82 mm and a puncture depth of 52.8+9,9 mm and the control group had 58.28k12.56. Time to start puncture was 5.22-t-1.46 min and in the control group 4.43f2.04 min. VAS after puncture was 0.69k1.16 in the ultrasound group and 1.27&l .86 in the control group. Patients acceptance (scale from l=very good to 6=insufficient) was higher in the ultrasound group: 1.2 + 0.5 than in the control: 1.8k1.13. Complications [ultrasound/control] were mild headache (O/7) backpain [ 1 O/14] continence problems (l/2) sensibility disorders (O/4) and no complications were detected in (35/50) patients. In both groups we had no drop-out but we had two failures in trying to achieve sufficient analgesia.

Conclusion: Our findings suggests that ultrasound is a useful method for the detection of the epidural space. Puncture quality and results regarding pain relief and patients acceptance after epidural analgesia were better than in the control group. The ultrasound technique can be a useful method to improve epidural anesthesia.

23. Preliminary impressions of PCA Remifentanil on delivery suite

R. G. Wilkes*, B. V S. Murthyt, S. Mallaiah*, S. M. Burns* *Liverpool Women’s Hospital and fRoya1 Liverpool University Hospital, Liverpool, UK

Introduction: Remifentanil used in labour may offer the benefits of potency, rapid offset and titrabi1ity.Q With Ethics Committee approval we have examined the use of PCA remifentanil for women in labour with a non viable fetus and observed its safety and efficacy. Here we show preliminary impressions.

Methods: In each case a Graseby 9300 pump was used. Boluses were administered over one minute. Remifentanil was started at the patient’s request and the dosing schedule was altered as necessary. Patients were observed for any adverse effects.

Results: Each diagram (Figure) represents the patient’s labour up to delivery of the fetus. The use of PCA remifentanil is indicated as are any necessary dose adjustments. No serious untoward effects occurred. A brief self-correcting desaturation to 90% occurred in the second patient. All women remained stable afterwards.


a b C d e f

time=3h approx. (15 midcm)

a: pre remifentanil; b: 0.05 ug/kg bolus, 3 min lockout; c: 0.075 ug/kg bolus, 3 min lockout; d: 0.1 ugfkg bolus, 2 min lockout; e: 0.1 ug/kg bolus, 2 min lockout; f: 0.125 ug/kg bolus, 2 min lockout; (request for epidural made) g: epidural analgesia, second stage.

h time=2.8h approx. (14minkm)

I j k

h: 0.125 uglkg bolus, 1 min lockout; i: 0.15 uglkg bolus, 1 min lockout; j: 0.175 ug/kg bolus, 1 min lockout; k: PCA empty; Entonox for second stage.

I m n 0 P time=7.4h approx. (37 minkm)

I: pre remifentanil; m: 0.09-0.15 ug/kg bolus, 1 min lockout; n: 0.18 ug/kg bolus 1 min lockout; o: 0.2 pg/kg bolus, 1 min lockout; p: required dose exceeding protocol limits; intramuscular diamorphine used. (Active second stage started fifteen minutes before delivery.)

Conclusions: Our dosing schedule for the first patient was ineffective. In particular, the lockout period was too long. However, the subsequently upgraded dosing schedule enabled us to provide improved analgesia for the other two patients. We have since continued to use PCA remifentanil in our unit. Remifentanil appears to be safe at the doses used but patients must be monitored with vigilance.

REFERENCES

1. Thompson JP, Rowbotham DJ. Remifentanil an opioid for the 21”Lcentury. Br J Anaesth 1996; 76: 341-343.

2. Servin F. Remifentanil: when and how to use it. European Journal of Anaesthesiology Suppl. 1997; 15: 4144.

24. Definitions in obstetric anaesthesia: how should we measure anaesthetic workload and what is ‘epidural rate’?

S.M. Yentis,* P.N. Robinson? *Magi11 Dept. of Anaesthesia, Chelsea and Westminster Hospital, London and fDept. of Anaesthetics, Northwick Park Hospital, Harrow HA1 3 UJ, UK

Introduction: Crude delivery rate is used to calculate requirements for consultant anaesthetic sessions in

the UK, but arbitrarily and ignoring casemix. The term “epidural rate” is commonly used to indicate regional anaesthetic activity but has never been defined. We challenge both of these concepts.

Methods: Data prospectively collected using the same computerised system at our hospitals (1994-97) were examined. (i) Numbers of deliveries and anaesthetic interventions (regional anaesthetics for labour + all caesarean sections, instrumental deliveries and third stage/other theatre procedures) were obtained. (ii) Different definitions of obstetric anaesthetic activity were calculated:

1.

2.

3.

4.

5.

number of women receiving an epidural, spinal or CSE where the indication was ‘labour’ + total number of labours. number of women receiving an epidural, spinal or CSE where the indication was ‘labour’ or ‘instrumental delivery’ + total number of labours. number of women receiving an epidural, spinal or CSE where the indication was ‘labour’ or ‘instrumental delivery’ t total number of deliveries. number of women receiving an epidurdl, spinal or CSE for any indication + total number of deliveries. number of women receiving any anaesthetic intervention + total number of deliveries.

Results: Data from 23 692 deliveries were analysed. Despite having fewer deliveries than Northwick Park, there were consistently more anaesthetic interventions at the Chelsea & Westminster. Activity rates differed widely according to the above definitions (Table).

Table

C&W 1994 1995 1996 1997

Number of deliveries Number of anaesthetic interventions Definition 1 Definition 2 Definition 3 Definition 4 Definition 5

NPH Number of deliveries Number of anaesthetic interventions Definition 1 Definition 2 Definition 3 Definition 4 Definition 5

t 2807 3209 3609 t 2259 2488 2764

43.5% 44.6% 40.9% 53.6% 56.10/o

42.5% 43.5% 39.5% 53.1% 55.3%

42.8% 43.8% 39.1% 53.9% 56.1%

1994 1995 1996 1997 3382 3471 3377 3831 1 a47 1955 2050 2349

31 .I% 32.2% 30.2% 38.8% 41.4%

29.5% 3 5 .2’%, 29.8% 35.5% 27.4% 32.8%) 38.9% 42.0% 42.2% 44.2%

35.2% 35.9% 32.4% 45.6% 47.7%

C & W = Chelsea & Westminster; NPH = Northwick Park; t = computerised system not in place.


Discussion: Number of anaesthetic interventions is better than delivery rate for estimating anaesthetic workload because it accounts for:

regional analgesia rate in labour caesarean section rate instrumental delivery rate. high-risk cases (these having higher intervention rates).

It does not include:

l monitoring, general advice l antenatal/postnatal assessments l antenatal education.

Delivery rate accounts for none of these points. The number of interventions worthy of one consultant session remains to be determined.

Any attempt to collect data nationally is meaning- less unless a single definition of regional anaesthetic activity is adopted by all contributing units. We suggest this definition should be the simplest and easiest to collect, and suggest definition 4 fulhls these criteria despite definition 1 being perhaps closer to what is generally considered ‘epidural rate’. The term ‘regional anaesthesia rate’ should replace “epidural rate”.

ACKNOWLEDGEMENTS

We are grateful to Ciconia Healthcare Systems Ltd for performing the data analysis.

25. Anti-infective measures and Entonox equipment - a survey

R. Turner, S.M. Yentis Magi11 Dept. of Anaesthesia, Chelsea & Westminster Hospital, London.

Introduction: Cases of cross-infection with hepatitis C from breathing equipment have led to the recommendation that an anti-infective filter or fully disposable breathing system is used for each new patient.] Whilst investigating methods of complying with this recommendation with respect to Entonox apparatus in our labour ward, we conducted a survey of other units to determine what measures were being taken.

Methods: 50 maternity suites were randomly selected from the Directory of Emergency & Special Care Units, 1996 (CMA Medical Data, Cambridge). We asked the person in charge of maintenance and/or cleaning of Entonox equipment what equipment was used, whether it was disposable or reusable and how often it was changed or cleaned.

Table Methods used by 50 units to clean/decontaminate Entonox equipment.

Component Method used number (%)

Tubing disposable - replaced after each case 0 sterilized ~ ever washed? after each case 13 (26%; washedt weekly 6 (12%) washed? monthly 10 (20%) washedt 3-6 monthly 3 (6%) never washed 1(14%) did not know 11 (22%)

Mouthpieces* disposable - replaced after each case 26 (52%) sterilized after each case 11 (22%) washed? after each case 12 (24%)

Filters disposable ~ replaced after each case 2 (4%) never used 48 (96%)

tin soapy water only; *one unit used facemasks only (washed after each case

Results: All 50 units provided information; the results are shown in Table 1.

Discussion: Although the prevalence of hepatitis C in pregnant women is uncertain, that of HIV is over 1:400 in UK inner cities.2 Other viruses that could be passed between patients via contaminated Entonox equipment include hepatitis B, Epstein-Barr and Herpes simplex viruses. Despite recommendations about anti-infective measures and the high cost of litigation should a case of cross-contamination occur, trusts are not taking steps to protect mothers from the risk of infection from Entonox equipment. This deficiency requires urgent attention.

ACKNOWLEDGEMENTS

We are grateful to the staff of the contibuting hospitals for supplying information to us.

REFERENCES

1. Report of the Blood Borne Viruses Advisory Panel. Association of Anaesthetists of Great Britain & Ireland, 1996.

2. Unlinked anonymous HIV prevalence monitoring programme, England &Wales. Department of Health, 1996.

26. Postpartum femoral neuropathy: more common than you think

A. Q. Dar, A. Robinson, G. Lyons Obstetric Anaesthethesia, St. James’s University Hospital, Leeds, UK

Introduction: At the start of the 20th century femoral neuropathy complicated up to 3.2% of vaginal deliveries. Modern obstetric practice, with increased


use of caesarean section and avoidance of prolonged labour, has substantially reduced the incidence of femoral neuropathy.’ The condition is now considered rare with only isolated cases appearing in the literature. We have attempted to quantify the current risk of postpartum femoral neuropathy in a UK teaching hospital. We report three cases of femoral neuropathy, collected over a 6-month period from February 1998 with an incidence of 1.5 per 1000 deliveries. Two had received regional analgesia in labour.

Cases: Case 1 had uncomplicated vaginal delivery of a 4.23 kg infant in conventional (semi-recumbent) position with epidural analgesia. The following morning, she complained of her right leg giving way when she first rose out of bed.

Case 2 delivered a 3.60 kg infant using vacuum extraction with epidural analgesia. She was in lithotomy position for a period of 90 min. Some 14 h later, when she was allowed out if bed, her right leg gave way and she could not walk. Case 3 had an uncomplicated vaginal delivery of a 4.16 kg infant in conventional position with transcutaneous electrical nerve stimulation and Entonox for analgesia. On the first postpartum day she described areas of numbness on both thighs.

After neurological examination, case 1 was diagnosed to have right sided femoral neuropathy which was confirmed on nerve conduction study. Cases 2 and 3 were diagnosed to have bilateral femoral neuropathies. All three patients were discharged home within 3 postpartum days with minimal sensory deficit and able to walk without support.

Discussion: Femoral neuropathy following vaginal delivery can be the result of direct compression of the nerve, proximally within the pelvis by either the fetal head or instruments, or the result of pressure induced ischaemia at the level of the inguinal ligament in lithotomy position. The diagnosis of femoral neuropathy was made on the basis of a sensory deficit in the distribution of the nerve and absent patellar reflex, with or without the presence of quadriceps weakness. The reduced or absent patellar reflex is the most reliable objective sign in femoral neuropathy. Nerve conduction studies can be used to confirm the diagnosis. Postpartum femoral neuropathy is associated with a good prognosis and is consistent with a neuropractic injury where axonal loss is less than 50%*. Improvement is to be expected within 2 to 8 weeks and full recovery within 6 months.

Conclusion: Femoral neuropathy is a relatively common complication of childbirth (1.5:1000) and

has a variable presentation. It is almost always self- limiting and full resolution is the rule. Once diagnosed, conservative management and reassurance are all that is needed.

REFERENCES

1. Donaldson JO. Maternal obstetric palsies. In Neurology of Pregnancy, 2nd Ed, W.B. Saunders: London, 1989; 45-46.

2. Kuntzer T, Melle GV and Regli F. Clinical and prognostic features in unilateral femoral neuropathies. Muscle and Nerve. 1997; 20: 205-211.

27. Low-dose CSE analgesia for labour: influence of cephaladkaudad Wbitacre needle orientation.

T. Mumtaz, A. Shawe, J.A. Crowhurst, F. Plaat Queen Charlotte’s Hospital, London, UK

Background and goal of study: Several studies of high- dose spinal anaesthesia have shown that mechanisms of injection can alter intrathecal local anaesthetic distribution.1,2 The aim of this study is to determine if injection directed cephalad (group A) or caudad (group B) affects the distribution of sensory and motor blockade with low-dose combined spinal- epidural analgesia (CSEA).

Materials and methods: After ethics committee approval 40 women in labour consented and were studied. CSEA was administered in the left lateral position with a 27 gauge Whitacre needle at L2-3. Parturients were randomly assigned to group A or B. All mothers received 2.5 mg of isobaric bupivacaine and 25 pg fentanyl (1.5 ml total volume) over 10 seconds and an epidural catheter left in situ for later use. Five minutes later, all women were placed in a semi- recumbent position and routine maternal and fetal monitoring instituted. A ‘blinded’ observer then carried out neurologic assessments and visual analogue pain scores at 5-min intervals for 30 minutes. Sensory blockade was tested using loss of temperature (ethyl chloride) and pin-scratch (Neurotips). Motor block was assessed with reference to specific myotomes. A score of 0 is assigned for no block and 1 for complete block at each joint on both sides, hip flexion (L2), knee extension (L3), ankle dorsiflexion (L4), great toe dorsiflexion (L5), ankle planter flexion (Sl).’ Bromage scores were noted at the same time. Block of S2-S4 was assessed by direct questions about pelvic floor tone. The time to first epidural top-up request and the ability to ambulate were noted. Statistical analysis was performed by Student’s t-test and Mann Whitney U tests.

Results and discussion: The two groups were comparable in age, weight and height. All parturients had adequate analgesia with a similar onset time but a


longer duration in the cephalad group (PcO.001). The mean sensory level achieved (up to 20 min) was significantly higher in the cephalad group (P<O.OOl). This was not associated with any haemodynamic or fetal cardiotocographic changes. Initial degree of motor block was similar in the two groups (mean myotome score of 34) but after 1.5 min it was found to be significantly reduced in group A group (P~O.009). Motor blockade below S2 (i.e. the pelvic floor) was noted to be dense throughout the study period in all patients.

Conclusion: We conclude that Whitacre needle orientation exerts a major influence on distribution and duration of sensory and motor blockade in low- dose CSEA in labour. Our study has confirmed earlier observations that a cephalad-directed injection is the preferred method to achieve selective CSEA with the ability to ambulate 230 minutes after the spinal injection.4

REFERENCES

Urmey W F. The direction of the Whitacre needle aperture affects the extent and duration of isobaric spinal anesthesia. Anesth Analg 1997; 84: 337-341. Graham C W, Sutton L. Directional spinals in obstetric analgesia. Anaesthesia 1978; 33: 192-195. Seow L T, Cousins M J. Lidocaine and bupivacaine mixtures for epidural blockade. Anesthesiology 1982; 56: 177-l 83. Plaat F, Singh R, Crowhurst JA. Selective sensory blockade with low-dose combined spinal epidural allows safe ambulation in labour: a pilot study. International Journal of Obstetric Anesthesia 1996; 3: 220.

28. Three-month audit of incidence, management and outcome of preleclampsia at Queen Elizabeth Central Hospital, Blantyre, Malawi

I. Boyne,* F. Taulof- *Dept of Anaesthesia, Eyob Tadesse and fDept of Obstetrics and Gynaecology, Queen Elizabeth Central Hospital, PO Box 95, Blantyre, Malawi

Introduction: No data were available on preleclampsia in Malawi. An audit of incidence and current management of pre/eclampsia in our hospital, which is tertiary referral centre to Southern Malawi, was conducted, including maternal and neonatal outcome.

Methods: This audit was conducted in August, September and October 1998 by daily visits to labour ward and the obstetric theatre to take details from the delivery and theatre books. Short ward rounds were done to reduce the number of cases missed by incomplete entry of data into the delivery book. A questionnaire was completed for every patient with pre/eclampsia. Patients were followed up on day one post-delivery.

Results: Data collection proved difficult. 3370 deliveries were recorded, 96 patients with pre/eclampsia; on 9 1 data from the questionnaire were available. The overall incidence of pre/eclampsia was 2.8%, of eclampsia 0.6%. 24% of parturients with pre/eclampsia were delivered by CS in comparison to 47.4% of eclamptic patients and an average CS rate of 14.9%. 88% received iv. diazepam combined with i.v. hydralazine in 53.8%, oral anti-hypertensive treatment or seizure prophylaxis were also given. Intravenous drip rates were very variable. Diastolic blood pressures (DBP) were recorded in the questionnaire on admission to labour ward, highest intra-partum and post-partum values. All 91 patients were hypertensive at some stage. DBP 2110 were present in 24% on admission, 25% intra-partum with 14 patients never having an intra-partum measurement and 21% post-partum. All 23 patients who were delivered by CS were anaesthetised by anaesthetic clinical officers (paramedical). They follow guidelines which include hydralazine to reduce pre-induction DBP to ~110, induction with thiopentone, followed by suxame- thonium for intubation and halothane for maintenance via a draw-over system.

Maternal outcome: Two deaths were recorded, one in an eclamptic patient who died on admission to labour ward and one in a preeclamptic patient who suffered intra-partum stroke and died 2 weeks later. Three patients were admitted to ICU post-CS because of uncontrollable blood pressure, cerebral or respiratory problems requiring intubation and ventilation and multiple drug administration.

Neonatal outcome: 92 live births, seven stillbirths and four neonatal deaths. Neonatal Apgar one minute <5 in 40% (pre/eclamptic mothers) in comparison to an average rate of 9.1% in labour ward.

Conclusion: There is room for a lot of improvement: record keeping, intra-partum monitoring, drug administration, hydralazine in preference to diazepam as anti-hypertensive treatment. A protocol for management of pre/eclampsia is existent and should be implemented soon. Magnesium as part of a multi-centre study might be desirable.

REFERENCES

Jamelle RN. Eclampsia - a taxing situation in the Third World. International Journal of Gynaecology & Obstetrics 1997; 58: 311-312. Mwinyoglee J, Amoko DH, Simelela N, Marivate M. Eclampsia at Ga-Rankuwa Hospital. South African Medical Journal 1996; 86: 15361539. Makhseed M, Musini VM. Eclampsia in Kuwait 1981-1993. Australian & New Zealand Journal of Obstetrics & Gynaecology 199636: 258-263.


29. A report on maternal mortality in Uganda, based on personal experience

N. Smith Currently specialist registrar at the Royal Free Hospital, London, UK

Introduction: The World Health Organisation has estimated that over half a million women die each year due to pregnancy, 99% of these in developing countries.’ I worked as a volunteer in the anaesthetic department at the Mbarara University of Science and Technology Hospital in the rural south-west of Uganda for almost 2 months in 1998, and developed an interest in maternal and infant health due to my experiences there. Although it is not easy to obtain correct and inclusive statistics, the incidence of maternal mortality in Uganda is estimated to be anywhere between 500 and 2000 per 100 000 deliveries - 1200 is the widely accepted average figure. The figure in the UK is six per 100 000 deliveries, as reported in the 199 1-l 993 Confidential Enquiries into Maternal Deaths in the UK.2

Causes of maternal mortality: The teaching hospital in the capital city of Uganda, Mulago Hospital, carried out a survey in 1997 of causes of maternal mortality. These were presented at an anaesthetic conference in Mbarara in March 1998 (Fig. 1).

HIV related complications were often meningitis or pulmonary infections such as tuberculosis, often with diarrhoea, dehydration, and severe wasting and weakness. Haemorrhage included antepartum haemorrhage, postpartum haemorrhage, and the relatively common condition of ruptured uterus. That anaemia was such a high proportion is a reflection of the prevalence of malaria, and its increasing resistance to chloroquine. The sepsis category specifically excluded HIV-related infection, and included overwhelming infection secondary to ruptured uterus or prolonged labour. Separate data are not available for the effects of anaesthesia, but it is thought to be a significant factor.

Contributing factors: Knowledge database. Com- munication and record keeping are poor, and it is not clear what proportion of pregnancies and deliveries occur outside medical facilities. Early in 1997, the Ugandan government launched a nationwide campaign called the Safe Motherhood Programme, and one of its first objectives has been data collection.

Assessment of needfor help. Delay in deciding to seek medical help has been described as a major factor in maternal mortality elsewhere in the developing

Other -...-. 3.6% Abortion

HIV related 40.0%

Hypertension 3.6% Sepsis

7.8%

Figure Causes of maternal mortality in Mulago Hospital - 1997.

world,3 and seems to be an important problem in Uganda. Many villagers will only seek help when a complication has developed. A scenario that I have seen is that of a man bringing his wife to hospital on the back of a bicycle after she has been in labour in the village for several days ~ by then the baby was dead, and the mother septic and shocked from a ruptured uterus on top of her usual anaemia.

Transport. The main method of transport for many villagers is the bicycle. The mean distance to reach a hospital in Uganda has been calculated at almost 13 km.

Normal birth practices. It has been estimated that 35% of deliveries in Uganda are assisted by a relative, 50% by a local birth attendant, only 4% by a doctor, and 12% by no-one at all. In my experience, high-risk pregnancies are not often identified early, and caesarean sections are rarely planned electively. Caesarean section is the most common operation performed in Uganda. It constitutes approximately 60% of all operations, and 90% of all emergency operations.

Age. It is estimated that approximately 43% of teenagers in Uganda either are or have been pregnant and that these teenagers account for approximately 30% of the maternal mortality.’ In the hospital in which I worked, 12% of caesarean sections were on women aged 13-l 8 years of age. Over half of these were for obstructed or prolonged labour, 14% were for ruptured uterus, and another 14% were for a previous scar. Fortunately, there was no mortality in this group in my time there, although approximately 20% of the babies delivered by caesarean section in theatre were stillborn.

Provision of adequate care at a health facility: Another survey examined the resources available within health clinics in one district in Uganda.’ Overall, 76% of clinics offered antenatal care, with less offering


normal delivery care. Only 60% of staff doing deliveries had any training, and over 50% of the normal delivery records were incomplete or poor. An alarmingly small proportion had a working system for blood pressure measurement. Less than half the clinics had any equipment for neonatal resuscitation. This implies that even when a woman reaches a health clinic, the care received there may be sub-optimal.

Conclusion: The plight of African women could be summarized as: neglected as children, married as adolescents, poor and illiterate, traditional practices, underfed and overworked, worth is defined by number of children, and the births are too many, too close, too early, and too late. Strategies that have been defined in Uganda to improve the problem of high maternal mortality include not only improved medical training,

equipment, and care in hospitals and clinics, but also improved infrastructure within the community, improved understanding of pregnancy and general health issues in all levels of the community, continued research, and on the establishment of this issue as a major health priority.

REFERENCES

AbouZahr C, Wardlaw T, Stanton C, Hill K. Maternal mortality. Maternal Health and Safe Motherhood Programme, WHO, Geneva. World Health Statistics Quarterly. 1996; 49: 77-87. Department of Health. Report on confidential enquiries into maternal deaths in the United Kingdom 1991-1993. London, HMSO 1996. Barnes-Josiah D, Myntti C, Augustin A. The ‘three delays’ as a framework for examining maternal mortality in Haiti. Social Science and Medicine 1998; 46: 981-993.

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Abstracts of free papers presented to the Obstetric Anaesthetists” … · 2011-08-10 · Abstracts of free papers presented to the Obstetric Anaesthetists’ Association meeting,