exemple subiecte EDAIC Part 1 publicate in newsletter-ul ESA si afisate, pana in ianuarie 2015 inclusiv, pe: https://www.esahq.org/resources/publications/quarterly-esa-newsletter

newsletter 2012 autumn (n-am gasit subiecte in newsletter-ele mai vechi)

Multiple choice questions // Each question has only one correct answer (de fapt pot fi mai multe). Answers will be published in the next issue of the Newsletter.

1. Total T4 level in serum:a. has a reciprocal relationship with the free T3 levelb. is controlled by calcitonin from the C-cells of the thyroid c. is affected by the level of thyroxine binding globulind. is controlled via a posterior pituitary hormonee. is elevated by growth hormone

2. Uptake of inhalational anaesthetics across the alveolar-capillary membrane is affected by:a. the partial pressure difference between the alveolar gas and that dissolved in bloodb. membrane thicknessc. the presence of nitrous oxide within the alveolus d. the cardiac outpute. hyperventilation

3. In type II halothane-induced hepatotoxicity:a. severity of injury increases after each useb. injury is invariably dose relatedc. cross reactions with other volatile agents occur d. specific treatment includes high dose steroids e. injury never occurs on first exposure

4. A gas chromatograph can be used to measure the:a. concentration of nitrous oxide in a gas mixture b. concentration of CO2 in expired airc. concentration of a volatile agent in a gas mixture d. blood pHe. plasma thiopental level

5. The Chi-squared test ( 2):χa. is an example of a parametric testb. requires calculation of the squared (observed-expected frequencies), divided bythe expected frequency, for each cell of the contingency tablec. Yates’ continuity correction is normally applied for a 2 x 2 table where oneexpected value is less than 5d. Fisher’s exact test is preferred for a 2 x 2 contingency table

e. a 2 x 2 contingency table has 3 degrees of freedom

newsletter 2013 winter

Preparation for EDAIC // Answers / These are the answers to the questions posed in the previous newsletter. T= True, F=False

1. Total T4 level in serum:a. has a reciprocal relationship with the free T3 levelb. is controlled by calcitonin from the C-cells of the thyroid c. is affected by the level of thyroxine binding globulind. is controlled via a posterior pituitary hormonee. is elevated by growth hormoneAnswers: a)F b)F c)T d)F e)FExplanation:The levels of total T3 and T4 are not strongly correlated in normal subjects. T4 is carried in the plasma by thyroxine binding globulin (TBG), which is normally only 25% saturated: changes in TBG levels will affect total T4 but not free T4. T4 is controlled by TSH from the anterior pituitary, which is released under the control of TRH from the hypothalamus. Growth hormone acts synergistically with T4 but does not affect plasma levels of T4.

2. Uptake of inhalational anaesthetics across the alveolar-capillary membrane is affected by:a. the partial pressure difference between the alveolar gas and that dissolved in bloodb. membrane thicknessc. the presence of nitrous oxide within the alveolusd. the cardiac outpute. hyperventilationAnswers: a)T b)T c)T d)T e)TExplanation:Movement of volatile agent from alveolus to capillary depends on the concentration gradient (difference in partial pressure), distance to diffuse (membrane thickness), the second gas effect - nitrous oxide diffuses into the capillaries faster than nitrogen exits the capillaries, so concentrating the volatile agent in the alveolus and increasing the concentration gradient; a high cardiac output slows and a low cardiac output speeds uptake of volatile agent; increasing minute ventilation speeds uptake (hyperventilation) and lowering minute ventilation slows uptake.

3. In type II halothane-induced hepatotoxicity:a. severity of injury increases after each useb. injury is invariably dose relatedc. cross reactions with other volatile agents occur d. specific treatment includes high dose steroids e. injury never occurs on first exposureAnswers: a)T b)F c)T d)F e)F

Explanation:Type I halothane hepatitis is common and self-limiting, type II rare and fulminant. Previous exposure produces antibodies against the haptensformed during halothane metabolism, early re-exposure can then produce a greater response. This adverse reaction is immune, not not dose-related and requires a genetic predisposition. Other volatile agents that produce similar oxidative metabolites can also trigger hepatotoxicity. Steroids have not been shown to be beneficial. First exposure can be associated with hepatotoxicity, although more commonly it is seen on second or subsequent exposure particularly if close in time (within 6 weeks).

4. A gas chromatograph can be used to measure the:a. concentration of nitrous oxide in a gas mixture b. concentration of CO2 in expired airc. concentration of a volatile agent in a gas mixture d. blood pHe. plasma thiopental levelAnswers: a)T b)T c)T d)F e)TExplanation:Gas chromatographs can identify compounds in a mixture that can be converted into a volatile form without degrading, including compounds in solution such as thiopental. Blood pH is determined by hydrogen ion concentration, not hydrogen gas concentration.

5. The Chi-squared test (X2):a. is an example of a parametric testb. requires calculation of the squared (observed-expected frequencies),divided by the expected frequency, for each cell of the contingencytablec. Yates’ continuity correction is normally applied for a 2 x 2 table whereoneexpectedvalueislessthan5d. Fisher’s exact test is preferred for a 2 x 2 contingency table e. a 2 x 2 contingency table has 3 degrees of freedomAnswers: a)F b)T c)T d)T e)FExplanation:The Chi-squared test is a non-parametric test commonly used to identify an association between categorical variables. The value of the Chi-squared statistic is calculated as: ∑ (O-E)2/E where O and E are the observed and expected frequencies for a given cell of the contingency table. The continuity correction (Yates’) is used in 2 x 2 tables to allow for the approximation of a discrete distribution by a continuous one, more commonly for tables with small numbers of expected frequencies - fewer than 5 expected observations in one cell is the generally quoted limit. Fisher’s exact test was recommended only for 2 x 2 tables before the advent of computers and acceptable computational methods. It calculates the exact probability of the observed distribution of events occurring rather than the approximate method used by the Chi-squared test and works best when there is an uneven distribution of observations in rows/columns. It is still preferred for small numbers of

observations and a 2 x 2 table. The number of degrees of freedom for any contingency tableis(numberofrows-1)x(numberofcolumns-1)sofora2x2table thisis(2-1)x(2-1)=1x1=1.

Preparation for EDAIC // Multiple Choice Questions for Part 1 (more than one answer could be correct for each questions) Answers will be published in the next issue of the Newsletter.

1. In a patient with a hiatus hernia, anaesthetic complications at induction can be reduced bya. the use of ketamineb. preoperative therapy with H2 receptor antagonists c. the use of cricoid pressured. the use of a laryngeal maske. atropine premedication

2. Factors known to influence total respiratory compliance during anaesthesia includea. changing depth of anaesthesiab. administration of depolarising muscle relaxantsc. duration of anaesthesiad. body positione. pneumoperitoneum

3. Possible complications of right-sided supraclavicular brachial plexus block includea. Horner's syndromeb. phrenic nerve paralysisc. recurrent laryngeal nerve paralysisd. damage to the thoracic ducte. subclavian artery puncture

4. In a patient with low intracranial compliance, cerebrospinal fluid pressureis directly increased bya. hypercarbiab. hypoxiac. isofluraned. ketaminee. propofol

5. In a patient suffering from a thyroid crisis, suitable treatment includesa. beta adrenergic blockadeb. digoxinc. corticosteroidsd. nasogastric potassium iodide e. intravenous methimazole

In the next issue of the newsletter the correct answers and explanations will be given.Dr Sue Hill, Chairman Part I EDAIC Subcommittee

newsletter 2013 spring

Preparation for EdAIC // Answers / These are the answers to the questions posed in the previous Newlsetter T= True, F= False

1. In a patient with a hiatus hernia, anaesthetic complications at induction can be reduced bya. the use of ketamineb. preoperative therapy with H2 receptor antagonistsc. the use of cricoid pressured. the use of a laryngeal maske. atropine premedicationAnswers: a) F b) T c) T d) F e) FExplanation: The main risk with hiatus hernia is aspiration causing reduced respiratory function: ketamine will not affect the risk of aspiration; H2 blockers will reduce the acidity of stomach contents and reduce the effects of acid aspiration; cricoid pressure reduces aspiration risk; use of a laryngeal mask will not prevent aspiration; atropine premedication blocks cholinergic effects but does not affect passive aspiration.

2. Factors known to influence total respiratory compliance during anaesthesia includea. changing depth of anaesthesiab. administration of depolarising muscle relaxantsc. duration of anaesthesiad. body positione. pneumoperitoneumAnswers: a )T b) T c) F d) T e)TExplanation: Total respiratory compliance is a combination of chest wall compliance and pulmonary compliance. Changing depth of anaesthesia alters muscle tone and so alters chest wall compliance; all muscle relaxants increase chest wall compliance; duration of anaesthesia has no specific effect on respiratory compliance; position will affect chest wall compliance in particular the prone position; pneumoperitoneum can splint the diaphragm and so reduce pulmonary compliance.

3. Possible complications of right-sided supraclavicular brachial plexus block includea. Horner's syndromeb. phrenic nerve paralysis

c. recurrent laryngeal nerve paralysisd. damage to the thoracic ducte. subclavian artery punctureAnswers: a) T b) T c) T d) F e) TExplanation: This is an anatomy question: know the anatomy of the brachial plexus, in particular its relations. Temporary Horner’s syndrome is cause by proximal spread and blockade of sympathetic afferents; ipsilateral phrenic nerve paralysis is common; ipsilateral recurrent laryngeal nerve palsy can occur but much less frequently than Horner’s or phrenic nerve palsy; the thoracic duct is on the left, so a right sided block will not damage it; the subclavian artery is at risk of puncture in this block, but with modern ultrasound-guidance this is much less likely than in the past.

4. In a patient with low intracranial compliance, cerebrospinal fluid pressure is directly increased bya. hypercarbiab. hypoxiac. isofluraned. ketaminee. propofolAnswers: a) T b) T c) T d) T e) FExplanation: This is a neuroanaesthesia question. Low intracranial compliance suggests a patient on the threshold of raised intracranial pressure so any factors increasing cerebral blood volume will increase CSF pressure: hypercarbia, hypoxia, volatile agents all increase blood volume by vasodilatation whereas propofol does not. The effect of ketamine is to increase cerebral metabolic rate (CMR) with a concomitant increase in cerebral blood flow and hence a rise in ICP. There is some debate over this action of ketamine and more recent opinion is that there is no rise in ICP as long as there are adjuvant drugs to reduce CMR such as opioids or propofol. Miller’s textbook states that ketamine is associated with raised ICP and this is the expected answer.

5. In a patient suffering from a thyroid crisis, suitable treatment includesa. beta adrenergic blockadeb. digoxinc. corticosteroidsd. nasogastric potassium iodidee. intravenous methimazoleAnswers: a) T b) F c) T d) T e) FExplanation: This is an emergency medicine/intensive care question. Recommended acute treatment for thyroid crisis is beta blockade, glucocorticosteroids and intravenous propylthiouracil plus oral/ nasogastric iodine compounds. Arrhythmias may occur, but digoxin is not the antiarrhythmic of choice. Methimazole should be used orally once the crisis has been treated, not intravenously as initial therapy.

Preparation for the EdA // Multiple Choice Questions for Part IPaper A consists of 60 multiple True/False questions (MTF). Each question has five parts, each of which can independently be T or F. Of these 60 questions, 20 are physiology, 20 pharmacology, 18 physics and equipment and 2 statistics. The following five multiple True/False (MTF) questions have been taken from the EDA question bank for Paper A (Basic Science).

1. Cardiac output is decreased bya. a fall in core temperature to 30 oCb. increasing arterial PCO2c. a change from sinus to nodal rhythmd. a decrease in afterloade. panhypopituitarism

2. The following increase peristalsis of the small intestinea. vagal blockadeb. food intake distending the intestinec. stimulation of the splanchnic nervesd. adrenalinee. hypokalaemia

3. Lidocainea. is an esterb. is of use in the treatment of supraventricular tachyarrhythmiasc. does not cross the normal blood-brain barrierd. increases myocardial contractility in the normal hearte. commonly cause methaemoglobinaemia

4. Pancuronium bromidea. action is potentiated by volatile anaestheticsb. has pre-junctional effectsc. readily crosses the placental barrierd. is biotransformed in the livere. is more than 90% bound to plasma protein

5. The standard deviation (S.D.) of normally distributed dataa. is the square root of the varianceb. is the square of the standard error of the meanc. 68% of observations lie between 1 S.D. below and 1 S.D abovethe meand. 20% of observations lie outside 2 S.D. either side of the meane. is proportional to the mean valueIn the next issue of the newsletter the correct answers and explanations will be given.

Dr Sue Hill, Chairman Part I EDA subcommittee

newsletter 2013 summer

The following are the answers to the MCQ questions set in the previous issue of this newsletter. Explanations are given below each question.

1. Cardiac output is decreased bya. a fall in core temperature to 30 oC (T) b. increasing arterial PCO2 (F)c. a change from sinus to nodal rhythm (T) d. a decrease in afterload (F)e. panhypopituitarism (T)Cardiac output (CO) is the product of stroke-volume and heart rate, a reduction in either one alone will reduce CO. Bradycardia accompanies hypothermia and myocardial contractility is also reduced. Increasing PaCO increases sympathetic drive and CO increases. Loss of the atrial contribution to stroke volume reduces stroke volume. A reduction in afterload increases stroke volume and CO. Panhypopituitarism is associated with reduced growth hormone, which reduces ventricular muscle mass with a reduction in stroke volume.

2. The following increase peristalsis of the small intestinea. vagal blockade (F)b. food intake distending the intestine (T) c. stimulation of the splanchnic nerves (F) d. adrenaline (F)e. hypokalaemia (F)Peristalsis is controlled by the enteric nervous system and gastrointestinal hormones. Acetylcholine (ACh) is excitatory and adrenaline inhibitory. Blocking the vagus reduces ACh release and reduces peristalsis; splanchnic nerve stimulation inhibits peristalsis. Hypokalaemia reduces smooth muscle contractility and sopartly reduces peristalsis.

3. Lidocainea. is an ester (F)b. is of use in the treatment of supraventricular tachyarrhythmias (F) c. does not cross the normal blood-brain barrier (F)d. increases myocardial contractility in the normal heart (F) e. commonly cause methaemoglobinaemia (F)Lidocaine is an amide local anaesthetic that is used in the management of ventricular ectopics, particularly following myocardial infarction. It can cross the blood-brain barrier as it is a weak base that is only ionised at plasma pH. It reduces myocardial contractility like other amides. It is metabolised in the liver but does not cause methaemoglobinaemia, which is associated with procaine and benzocaine.

4. Pancuronium bromidea. action is potentiated by volatile anaesthetics (T)

b. has pre-junctional effects (T)c. readily crosses the placental barrier (F) d. is biotransformed in the liver (T)e. is more than 90% bound to plasma protein (F)Volatile agents reduce calcium release in skeletal muscle and potentiate the action of non-depolarising muscle relaxants. Fade is thought to be produced by a pre-synaptic effect of non-depolarising muscle relaxants. Pancuronium, like all non-depolarising muscle relaxants, is permanently changed and cannot cross lipid bariers such as the BBB and placenta. Pancuronum is mainly excreted unchanged by the kidney but is also metabolised in the liver by de-acetylation. Plasma protein binding of muscle relaxants is generally low compared with lipid-soluble drugs, that of pancuronium is around 30%.

5. The standard deviation (S.D.) of normally distributed dataa. is the square root of the variance (T)b. is the square of the standard error of the mean (F)c. 68% of observations lie between 1 S.D. below and 1 S.D above the mean (T)d. 20% of observations lie outside 2 S.D. either side of the mean (F)e. is proportional to the mean value (F)The standard deviation is the square root of the variance; the standard error of the mean is the standard deviation divided by the number of observations in the sample from which the mean was calculated. 68% of observations lie between +/- 1 S.D. on either side the mean, 5% of observations lie outside +/- 2 S.D. either side of the mean; 0.3% of observations lie outside +/- 3 S.D. of the mean. In a normal distribution, the mean and variance are independent of each other.

Dr. Sue Hill //Chairman Part I EDA subcommittee

EdAIC Paper B Questions //

1. Bilateral recurrent laryngeal nerve sectiona. causes complete airway obstructionb. causes respiratory difficultyc. causes tetanyd. allows adduction of the vocal cords on inspiratione. causes dysphagia

2. Early sequelae of near-drowning in sea water includea. cardiac dysrhythmiasb. haemolysisc. hypotensiond. atelectasise. seizures

3. The use of regional anaesthesia for Caesarian section is appropriate in patients witha. placenta praeviab. pre-eclampsiac. HELLP syndromed. mitral valve diseasee. Christmas disease

4. Ventricular fibrillation is likely to be initiated by an electrical stimulus during thea. PQ intervalb. ascending limb of QRSc. peak of QRSd. peak of the T wavee. interval between the S and T wave

5. In a patient suffering from a thyroid crisis, suitable treatment includesa. beta adrenergic blockadeb. digoxinc. corticosteroidsd. intravenous paracetamole. intravenous carbimazole

newsletter 2013 autumn

Answers & explanations // For each question, the answers are given as T = true or F=false. So for example, question 1, part A=false (F), part B=true (T), and so on.

1. FTFFFThis is an applied anatomy question relevant to head and neck surgery. Bilateral recurrent nerve injury leaves the vocal cords in a near-closed, midline position. This does not lead to complete obstruction although respiration is impaired. Parathyroid surgery is a cause of recurrent laryngeal nerve damage but also hypocalcaemia and tetany, but tetany is not caused by loss of laryngeal nerve function. The recurrent laryngeal nerve does not affect oesophageal function, so dysphagia is not a problem - the problem is with failure to protect the airway.

2. TFTFTThis is an intensive care question relevant to management of a patient with seawater near-drowning. Seawater has an osmolarity greater than plasma, so pulmonary oedema is a complication and haemolysis is not a problem, very different from near-drowning in fresh-water. Hypoxaemia and CO2 retention can lead to arrhythmias and seizures in both types of drowning. Atelectasis is more a feature of fresh water drowning because it disrupts surfactant function and causes closure of alveoli. Hypotension occurs with both types of drowning due to increased capillary membrane permeability and interstitial oedema.

3. FTFTFAn obstetric question, in the “special anaesthesia” section of Paper B, relating to contraindications to regional anaesthesia for C-section. Any pathological process affecting coagulation is a contraindication to such a technique so HELLP (haemolysis, elevated liver enzymes and low platelets) syndrome and Christmas disease (haemophilia B) are contraindications. Pre-eclampsia can be associated with low platelets, but not always low enough to make this a contraindication. Placenta praevia used to be considered a relative contraindication, but modern management shows a lower blood loss with regional as opposed to regional techniques.

4. FTTFFThis is an applied physiology question. The most sensitive period for an additional electrical impulse to trigger VF is during the QRS period, before this it may cause a premature contraction and after this the relative refractory period (S to T) reduces the risk of triggering an arrhythmia. The so-called R-on-T syndrome is not normally a risk for VT unless the patient has an abnormally prolonged QT interval. In such a question, assume the patient is physiologically normal unless told otherwise.

5. TFTTFThis is an applied pharmacology question relating to medical treatment. Beta-blockers, such as propranolol, reduce tachycardia and hypertension, glucocorticoids prevent peripheral conversion of T4 to T3 so are useful, Carbimazole is first-line treatment as an oral (not intravenous) medication to prevent uptake of iodine. Paracetamol will help in reducing the hyperthermia associated with a thyroid storm.

Preparation for the EDAIC // Multiple Choice Questions for Part I DR. SUE HILL // CHAIRMAN PART 1 EDAIC SUBCOMMITTEE // Paper A consists of 60 multiple True/False questions (MTF). Each question has five parts, each of which can independently be T or F. Of these 60 questions, 20 are physiology, 20 pharmacology, 18 physics and equipment and 2 statistics. The following five multiple True/False (MTF) questions have been taken from the EDAIC question bank for Paper A (Basic Science). The answers to these multiple True/False questions will be published in the next issue of this newsletter.

1. Regarding stretch reflexes:A. the knee-jerk is a monosynaptic reflexB. the latency of the human knee jerk is 200 msC. muscle contraction is a result of gamma-motor neurone activation D. the efferent component arises in anterior horn cellsE. nerves conducting the afferent component are unmyelinated

2. Drugs which decrease myocardial oxygen demand include:A. nitroglycerinB. dopamine

C. sodium nitroprussideD. isoproterenol (isoprenaline) E. amiodarone

3. Concerning the electromagnetic spectrum:A. individual wavelengths are proportional to the reciprocal of their frequency B. the frequency of X-rays is lower than of gamma raysC. the wavelength of ultraviolet is longer than that of infra-red lightD. radio waves have a lower frequency than X-raysE. oxygen is capable of absorbing the energy of high-frequency ultraviolet light

4. When using indirect measurement of arterial pressure:A. the width of the cuff should be 40% of the mid circumference of the armB. use of a normal cuff in an obese person would tend to underestimate the arterial pressureC. the systolic arterial pressure is normally slightly below that sensed by direct measurementD. Oscillometric methods require the sensing of both static and dynamic pressures changesE. in oscillometry the systolic pressure is determined at the point where the first pulse is sensed

5. Student's unpaired t-test is a statistical technique that:A. determines the degrees of freedomB. may be applied to a comparison of the means of two samples when the sample sizes are small C. avoids the use of the null hypothesisD. is used for comparing samples where the data are approximately normally distributedE. assumes p < 0.01 for significance

newsletter 2014 winter

 Answers and Explanations //

1. Regarding stretch reflexes: answers for parts a to e are: TFFTFThe knee jerk is a classic example of a monosynaptic reflex: just one synapse is involved in the anterior horn between the sensory afferent and the unilateral motor efferent. Stretch of the quadriceps activates its muscle spindles, which send a type Ia afferent sensory nerve signal to the spinal cord through the dorsal horn. This signal passes through the dorsal horn and synapses on the cell bodies of the alpha-motor neurones in the anterior horn that transmit the efferent motor signal that leads to contraction of the muscle. Type Ia sensory fibres are myelinated, rapidly conducting sensory nerves with their cell bodies in the dorsal root ganglia. Alpha motor neurones are also rapidly conducting, myelinated fibres. Both Ia and alpha motor neurones conduct at 80-120 m/s. The latency of the knee jerk is very short, much

less than 200 ms - around 20 ms. You could estimate this knowing the distance travelled from knee to spinal cord is around 1 m, so with nerves that conduct at 100 m/s 2 m will be covered in 2/100 s or 20 ms (synaptic transmission is so quick it can be discounted). Gamma-motor neurones are also activated causing contraction of intrafusal fibres within the muscle spindle; but it is the alpha-motor neurones that innervate the extrafusal fibres responsible for muscle contraction.

2.Drugs which decrease myocardial oxygen demand include: answers a-e: TFTFTMyocardial oxygen demand will be increased by drugs that increase the work of the heart and reduced by drugs that reduce the work of the heart. This question asked about drugs that reduce myocardial oxygen demand. This includes drugs that directly or indirectly reduce contractility - including those that reduce afterload and reduce heart rate. Therefore nitroglycerin and sodium nitroprusside reduce myocardial oxygen demand by reducing afterload and amiodarone by reducing heart rate. Dopamine and isoproterenol both increase the heart rate and so increase work of the heart and oxygen demand.

3. Concerning the electromagnetic spectrum: answers a-e: TTFTTThis basic physics question is not one of the mainstream topics, but nevertheless knowledge of the electromagnetic spectrum is important to our practice. The wavelength range of the electromagnetic spectrum is very wide but of importance to us. Approximate wavelength ranges, with longest first, is: the infra-red range (1 mm to 760 nm), the visible spectrum of colours (760 nm to 380 nm), ultraviolet light (between visible and X-rays, 1 - 380 nm), X-rays (1 Angstrom to 1 nm) and gamma-rays (0.1 Angstrom to 1 Angstrom). There is an inverse relationship between frequency and wavelength: the longer the wavelength the lower the frequency. Frequency (f) is equal to the speed of light (c) divided by the wavelength ( ) (f = λc/ ). Thus the order in terms of frequency (highest first) is: gamma rays; X-rays; λultraviolet; visible light; infra-red. Thus X-rays have a lower frequency than gamma rays and ultraviolet has a shorter wavelength than infra-red light. You should know that radio waves have much longer wavelengths, the frequency of broadcasts are in the 50 MHz to 1000 MHz - wavelengths vary between several hundred metres and a few millimetres. For completeness, the wavelength range of microwaves lies between radio waves and infra-red light. The ability of a substance to absorb the energy of electromagnetic waves and hence block their transmission depends on the material itself and the frequency of the wave in question. Oxygen can absorb high-frequency energy and hence can absorb electromagnetic radiation in the X-ray and UV part of the spectrum, but not visible light or waves with lower frequencies - otherwise radios or mobile phones could not function! Infra-red excites water vapour in air and is blocked for this reason.

4. When using indirect measurement of arterial pressure: answers a-e: TFTTFIndirect measurement of blood pressure involves manual or mechanical inflation of a blood pressure cuff and detection of pulsations. A properly-fitting blood pressure cuff is essential for accurate readings. The cuff should be 20% wider than the diameter of the part of the limb being used or cover two-third its length.

Since circumference is 2 r = d (r: radius; d: diameter) and theπ πvalue of is approximately 3, 40% of the circumference is 4/10 ofπ3d or 12/10 of d which is the same as 20% (2/10) greater than thediameter of the arm. A cuff that is too small tends to overestimateand a cuff that is too large underestimates the systolic pressures.In mechanical oscillometry, the cuff both inflates and senses the pulsations. The systolic pressure is recognised as the point where the rate of increase in the size of oscillation is maximal and diastolic pressure at the point of maximal rate of decrease in size of oscillation. Therefore oscillometry must measure both the value of the pressure pulse (static) and its rate of change (dynamic). Mean blood pressurevalues measured by oscillometry are accurate compared with direct, invasive measurement, but systolic is often a little lower and diastolic a little higher than when measured directly.

5. Student's t-test is a statistical technique that: answers a-e:FTFTFThe unpaired t-test attributed to “Student” (a pseudonym for William Gosset) is a parametric statistical test used to compare the mean values of two samples. It can be used for small or large samples. The two samples must be approximately normally distributed and have similar variances (within a factor of 3); there is no need for the sample sizes to be the same. All statistical test need a null hypothesis and the t-test is no exception; the null hypothesis is that there is no difference between the means. In order to perform the test the number of degrees of freedom must be calculated, the test does not calculate degrees of freedom (DoF). DoF depends on the sizes of the samples and is (n-1) + (m-1) where the two samples have sizes n and m respectively. The “p” value is set by the person designing the study, not assumed by the test, and is usually set at 0.05 or 0.01; only if p = 0,01 is specified does p < 0,01 indicate a significant result; if p is set at 0.05 then p < 0.05 is a significant result.

Part I EDAIC // Sample Questions // SUE HILL // CHAIRMAN PART 1 EDAIC SUBCOMMITTEE // sue.hill@uhs.nhs.uk

1. GastrinA. is a peptide hormone B. receptors are found on gastric parietal cells C. is produced in response to vagal stimulation D. is secreted into the stomach E. is a pancreatic enzyme

2. Central sedation is produced byA. hyoscine (scopolamine) B. clonidineC. droperidolD. glycopyrrolateE. magnesium

3.Inhalational anaesthetic agents with a blood-gas partition coefficient less than 1.0 include:A. sevofluraneB. nitrous oxideC. desflurane D. isoflurane E. xenon

4. The normal reaction of carbon dioxide with soda lime includesA. formation of sodium bicarbonate B. formation of calcium carbonate C. release of heatD.formation of waterE. liberation of carbon monoxide

5. Concerning central venous pressure (CVP) monitoringA.The presence of atrial fibrillation produces prominent 'a' wavesB. Third degree heart block produces giant 'v' wavesC. Tricuspid regurgitation produces cannon 'a' waves D.Pulmonary hypertension produces giant 'a' wavesE. Diastole begins immediately after occurrence of the 'c'wave

newsletter 2014 spring

Answers and Explanations

1. TTTFF This is a general physiology question. Gastrin is a peptide hormone produced by G-cells in the duodenum and stomach adjacent to the pylorus in response to digested protein (amino acids), vagal stimulation, hypercalcaemia and distention of the stomach. It is secreted into the blood stream and acts on the parietal cells of the stomach to increase hydrochloric acid secretion into the stomach lumen.

2. TTTFT This is a CNS pharmacology question. Hyoscine is an antimuscarinic agent that crosses the blood-brain barrier and can cause a number of central effects including sedation. It is mainly used for its antiemetic effects. Clonidine is an alpha2 adrenergic agonist that causes centrally mediated sedative effects. Droperidol is used as an antiemetic but also has sedative effects - it used to be used as part of an anaesthetic combination, fentanyl-droperidol, known as neurolept anaesthesia. Glycopyrrolate is an anticholinergic agent that contains a quaternary nitrogen and cannot cross the blood-brain barrier, so has no sedative effects. Magnesium can cross the blood-brain barrier and in pharmacological doses can cause central sedation and reduce the MAC of volatile agents.

3. TTFFTThis is also a CNS pharmacology questions but a very specific one. A low blood-gas partition coefficient (BGPC) is associated with a more rapid onset of anaesthesia. Newer volatile agents all have a low BGPC, below 1.0; sevoflurane, desflurane and xenon have BGPCs of 0.65, 0.42 and 0.14 respectively. Isoflurane, enflurane and halothane all have BGPCs above 1.0

4. FTTTFThis is a physics question. It asks about the reactions in the absorption of carbon dioxide by soda lime. Water and carbon dioxide form carbonic acid that reacts with the sodium hydroxide in soda lime to form sodium carbonate, not sodium bicarbonate, which in turn reacts with calcium hydroxide to form calcium carbonate and replenish sodium hydroxide. The reactions are exothermic - they produce heat. A slower reaction of carbonic acid with calcium hydroxide forms calcium carbonate and water. Thus the normal interaction between carbon dioxide and hydrated soda lime give water, sodium hydroxide and calcium carbonate as end-products. If the soda lime is left to dry out, then an abnormal reaction can lead to carbon monoxide production in the presence of volatile agents that carry the –CHF2 moiety (for example isoflurane and desflurane), but this is not normally seen.

5. FFFTF This is a clinical measurement question on interpretation of the CVP waveform. The waveform consists of three peaks (a, c, v) and two descents (x, y). The P wave of the ECG is followed by atrial contraction that is responsible for the a-wave. In atrial fibrillation co-ordinated atrial contraction is not present so the a-wave is not present. As the atrium relaxes, forming the x-descent, the R wave of the ECG is followed by isometric ventricular contraction that produces the c-wave due to back-pressure from the closed tricuspid valve. Once this valve opens the atrium continues to relax forming the y-descent. On closure of the tricuspid valve atrial filling takes place and the peak of the associated v-wave occurs during isovolumetric ventricular relaxation. Thus the a-wave and x-descent occur in diastole and the c & v waves with the y-descent in systole. Third degree heart block describes dissociation of atrial and ventricular contraction with more P waves than R waves. Atrial contraction is therefore independent of ventricular contraction and can occur when the tricuspid valve is closed which produces cannon a-waves (not v-waves). Tricuspid regurgitation occurs during systole and so affects atrial pressure once isovolumetric contraction has taken place, so the a-wave is not affected but there are tall c-v waves which obscure the x-descent. Pulmonary hypertension is associated with reduced right ventricular compliance and produces talla-waves.

Part I EDAIC // Sample QuestionsSUE HILL // CHAIRMAN PART 1 EDAIC SUBCOMMITTEE // sue.hill@uhs.nhs.uk

1. A decrease in thoracopulmonary compliance is associated withA. hyperventilationB. acute bronchospasmC. reverse Trendelenburg (head up) positionD. pulmonary oedemaE. induction of general anaesthesia

2. The following structures can be identified during endoscopic third ventriculostomy A. the foramen of MagendieB. the mammilary bodiesC. the pituitary glandD. the posterior inferior cerebellar arteries E. the basilar artery

3. Recognised causes of hypotension during spinal anaesthesia to T3 includeA. decreased heart rateB. increased venous capacitanceC. decreased stroke volumeD. direct myocardial depressionE. increased atrio-ventricular conduction time

4. Appropriate initial treatment of acute atrial fibrillation in the absence of heart failure includesA. diltiazemB. propranolol C. digoxinD. lidocaineE. amiodarone

5. A combination of decreased PaO2 and decreased PaCO2 is likely to be associated withA. congenital cyanotic heart disease B. diabetic ketoacidosisC. morphine overdoseD. hysteria-induced hyperventilation E. acute pulmonary embolism

Answers and explanations to these questions will be published in the next issue of the ESA Newsletter.

newsletter 2014 summer

Answers and Explanations // (T=True and F=False for each part of the questions)

1. Answers: FTFTTFactors that decrease thoracopulmonary compliance can be subdivided into into those that increase chest wall rigidity, those that make the lung parenchyma less easy to inflate and other factors that reduce lung expansion. Hyperventilation reduces carbon dioxide but does not affect compliance; bronchospasm and pulmonary oedema both reduce the ease of inflating the lung parenchyma whereas the reverse Trendelenberg position pushes abdominal contents toward the lungs and reduces the overall ease of expanding the lungs.

2. Answers: FTFFTThis is an applied anatomy question about the relations of the third ventricle related to clinical neuroanaesthesia practice. The endoscope generally enters a lateral ventricle, passes through the foramen of Munroe, not Magendie (these are outlets from the fourth ventricle), where the choroid plexus is visible. In the third ventricle the mammary bodies are seen immediately below the (usually) thinned and expanded floor of the third ventricle. Superior to the floor, the hypophyseal vessels can be seen as a “blush” entering the infundibulum but the pituitary gland cannot be seen. Once the ventriculostomy has been made, the basilar artery can be seen as it divides into the two posterior cerebral arteries. The posterior inferior cerebellar arteries arise from the vertebral arteries and cannot be seen.

3. Answers: TTTFFThere are several reasons for hypotension to accompany spinal anaesthesia when it is as high as T3. The sympathetic block of cadioaccelerator nerves allows predominant vagal activity contributing to a slowing of the heart rate. Sympathetic block leads to arterial and venous dilatation with an increase in venous capacitance; the drop in preload stimulates intrinsic cardiac mechanisms that also lead to lowering of the heart rate in the absence of sympathetic-mediated reflex vasoconstriction. The dose of local anaesthetic used in spinal, as opposed to epidural, anaesthesia means that no direct cardiac effects of the local anaesthetic are present.

4. Answers: TTFFFThis is an Emergency Medicine question. Acute atrial fibrillation (AF) should be treated with electrical shock if the patient is hypotensive, but this question is aimed at pharmacological treatment and in particular initial therapy. First-line therapy according to the European Resuscitation Guidelines indicate that diltiazem or beta-blockade are initial therapies. Digoxin and amiodarone - but not lidocaine (treatment of frequent ventricular ectopics only) - should be considered only if the patient is in heart failure.

5. Answers: FFFFFThis is an Intensive Care question. Cyanotic heart disease is associated with a reduction in PaO2 with hypoxic pulmonary vasoconstriction but little change in PaCO2. Diabetic ketoacidosis (DKA) is associated with hyperventilation and low PaCO2 secondary to respiratory compensation for a metabolic acidosis, but a

normal or slightly increased PaO2 (alveolar gas equation). Morphine overdose leads to hypoventilation and a fall in PaO2 but a rise in PaCO2. Self-imposed (hysterical) hyperventilation leads to a fall in PaCO2 and little change in a normal or slightly increased PaO2 similar to the situation in DKA. Acute pulmonary embolism causes a reduction in end- tidal carbon dioxide and a low PaO2 but a raised PaCO2 due to reduced blood delivery to the alveoli.

Sample Questions

1. The main buffers of hydrogen ions in the blood area. haemoglobinb. ammonium ions c. phosphated. bicarbonatee. albumin

2. Characteristic features of the blood supply to the spinal cord includea. autoregulation of blood flow is presentb. the lumbar region of the spinal cord is the most susceptible to ischemiac. paired posterior spinal arteriesd. reduced anterior spinal arterial supply affects mainly motor functione. the arteria radicularis magna (artery of Adamkievicz) arises from the vertebral arteries

3. Acute renal injury is a recognised toxic effect ofa. myoglobin b. ramiprilc. paracetamol d. cisplatine. morphine

4. Concerning rotametersa. in a variable orifice flowmeter only laminar flow occursb. at low flows the viscosity of the gas is the most important determinant of flowc. calibration is unaffected by the density of the gasd. a rotameter calibrated for nitrous oxide can also be used for carbon dioxidee. accuracy is independent of ambient temperature

5. Body weight of all adult male patients is normally distributed. This indicates thata. the mean and median weights are identicalb. exactly 50% of all weights fall within one standard deviation on either side of the meanc. exactly 90% of all weights fall within two standard deviations on either side of the meand. the mean and mode of the weights are not necessarily identicale. the variance of the weight is dependent upon the mean weight

Answers and explanations to these questions will be published in the next issue of the ESA Newsletter.

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newsletter 2014 autumn

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