2009 First Sitting

2009A 01: Pass rate: 50% The first part of the question is best answered by a labelled and annotated diagram of the ECG with the pressure events of the cardiac cycle. Common errors included mistiming of the ECG with the pressure waveform. The second part of the question could be answered in a tabular format such as: Interval Drug Mechanism PR Digoxin Increases refractory period of AV node probably by increased vagal activity QRS Tricyclic antidepressants Quinidine like effect, decreasing sodium influx into cells QT SSRI’s Malfunction of calcium ion channels Syllabus Cib2c, C2c2b References: Power and Kam 2nd edition p129 – 131, Stoelting and Hillier 4th edition p403, 409, 415

2009A 02: Pass rate: 10% The main points for a pass include a brief description of the citric acid cycle and a list of facts such as storage of CO2 (120L), production (200ml/min) and that 2 molecules of CO2 are produced for 1 molecule ATP. A statement that PaCO2 is proportional to CO2 production/alveolar ventilation would help answer the second part. An example of increased CO2 production is fever, and of decreased alveolar ventilation is increased anatomical dead space. Syllabus B1h 2e References: Power and Kam 2nd edition p78-79,101, Stoelting and Hillier 4th edition p790-791, Nunn 6th edition p148-156

2009A 03: Pass rate: 10% Marks were equally divided between all three parts. Structure to the answer using a table and list of facts gained credit. Factors affecting onset would be well described by stating Ficks law of diffusion and followed with an explanation of the equation. Factors affecting duration such as protein binding, regional blood flow, metabolism and use of vasoconstrictors scored marks. Regarding toxicity, an explanation of the CC/CNS ratio was required (the ratio of plasma levels at which CVSCollapse vs. Convulsions occur). Other factors included structure of agents, accumulation e.g. due to liver disease. A mention of features of particular agents’ toxicity such as prilocaine and methaemoglobinaemia was expected. Syllabus G2b 2a-c References: Peck, Hill and Williams 2nd edition p163-174 Stoelting and Hillier 4th edition p179-203 Evers and Maze p507-533

2009A 04: Pass rate: 40% Most candidates mentioned sweating, shivering, vascular response, and behavioural response to cold environment. Outlining the requirements of the temperature sensors, control processing area, and the effectors is, however, essential in order to pass this question. Most candidates did not mention where the temperature sensors are and the possible hormonal response to changes in the temperature of the environment. The interaction between interleukin-1 (and other pyrogens) and prostaglandin production in the hypothalamus was also not discussed. Syllabus section L1. Reference: Guyton & Hall 11th Edition page 894-901.

2009A 05: Pass rate: 10% Most candidates mentioned factor VIIa, Vitamin K, and desmopressin in their answers. Outlining the mechanism of action of the drugs used is essential in order to pass this question. The answers may include which coagulation factors are affected by warfarin and Vitamin K, the mechanism by which desmopressin promotes haemostasis and the multiple effects of Aprotinin. Topical treatment (e.g. adrenaline, glue) and drugs such as protamine, oestrogen, and tranexamic acid were common omissions. Syllabus J 2a 2 Reference: Stoelting and Hillier 4th edition page 449 and 607.

2009A 07: Pass rate: 20% Many definitions of afterload were accepted. The main factors affecting left ventricular afterload are systemic vascular resistance, aortic impedance and ventricular radius. Other factors include blood viscosity and positive intrathoracic pressure. Good answers expanded on the points above. Candidates who failed this question did not have enough facts. Syllabus C1c C2c Reference: Bray 4th edition p 342-344 and p 360-361

2009A 08: Pass rate: 20% Surface landmarks, anatomy of the trachea and its important relationships with the thyroid, carotid sheath and oesophagus were required to pass this question. Several candidates described the procedure of percutaneous tracheostomy in great detail. Descriptions of the procedure gained no marks. Syllabus B1b2g Reference: Anatomy for the Anaesthetist, Ellis and Feldman.

2009A 09: Pass rate: 40% Good answers were in tabular format. The antidepressant action is similar for each agent. Initial increase in 5HT and NA, followed in 2-3 weeks by a down regulation or change in efficiency of 5HT transmission. The agents produce elevated neurotransmitters via different mechanisms, either reuptake blockade or enzyme inhibition. MAOIs can be competitive or non-competitive. Mention of the different neurotransmitters affected by each agent was required. A description of significant side effects at therapeutic doses, and in overdose was expected with explanations provided. These should have included - the anticholinergic effects and cardiotoxicity of TCAs, postural hypotension, the catecholamine, pethidine and tyramine related complications of MAOIs, and serotonin syndrome with SSRI/MAOI use and or overdose. More marks were gained for mention that side effect profiles can be beneficial e.g. analgesic properties of TCAs, sedation with TCAs/ SSRIs and energizing benefits of SSRIs/SNRIs. SSRI’s safety and efficacy have markedly reduced the use of MAOIs and to a lesser extent TCA’s.. Syllabus G2f2d Reference: Stoelting p 398-407, Katzung p 476-487.

2009A 10: Pass rate: 30% Main points for a pass included the equations for determining the loading and maintenance doses. Points were awarded for explaining the rationale for giving a loading dose and for relevant diagrams. Answers to the second part of the question often lacked detail. Candidates should have mentioned alterations in volume of distribution, plasma proteins, renal & hepatic function. Examples of drugs illustrating an understanding of pharmacokinetics attracted extra marks. Syllabus II 2 f Reference: Rang Ritter Dale p120-123

2009A 11: Pass rate: 50% Good answers included an equation and then explored the various components of the equation. Main points for a pass included pressure and metabolic autoregulation and the various factors that affect cerebral vascular resistance. Graphs were a useful way to answer this question but were generally underutilised. Several candidates wrote about the Monro-Kellie doctrine which was not directly relevant to the question. Syllabus C1d2a Reference: Power and Kam 1st edition p 42-43, Guyton and Hall 11th edition p 761-3

2009A 12: Pass rate: 30% Though it would be unusual for patients to receive spinal opioids whilst they are in intensive care, the complications of spinal opioids are not an uncommon reason for admission to intensive care thus it is important candidates understand their pharmacology. Answers generally lacked structure. Outlining pharmacology should include pharmacokinetics, pharmacodynamics and side effects (both common and dangerous). An explanation of the effect of lipid solubility was expected. Following a structure will ensure a more complete answer. Syllabus G2d2e Reference: Neural Blockade. 3rd edition Cousins and Bridenbaugh

2009A 13: Pass rate: 30% The volume and composition of the glomerular filtrate are best explained by referring to the equation: Glomerular Filtration = Kf x net filtration pressure. Then describing the factors that affect each part of the equation e.g. hydrostatic pressure, oncotic pressure, factors that influence the filtration coefficient e.g. surface area Glomerular filtrate is an ultrafiltrate of plasma and factors that affect the passage of proteins and other molecules should be discussed Extra marks were given for an explanation of filtration fraction and short facts about GFR in paediatric patients and the elderly. No marks were given for any discussion of drugs. Syllabus D2b Reference; Power and Kam 1st edition p 197-199

2009A 15: Pass rate: 30% The following points were expected to be outlined in this question 1. The resting membrane potential (RMP) and its physiological basis 2. How the RMP changes rapidly after a stimulus e.g. electrical or chemical and reaches a threshold potential and an all or none action potential results 3. The ionic basis of the action potential 4. How the action potential is propagated 5. Factors that delay axonal conduction such as fibre size, myelination and electrolyte abnormalities e.g. hypermagnesaemia. Syllabus G2a Reference: Power and Kam 1st edition p 6-9

2009A 16: Pass rate: 40% The main points expected in this answer were descriptions of platelet activation following exposure to collagen, platelet adhesion to the endothelium and ADP release and platelet aggregation secondary to activation of the GP11b/111a, COX-1 and other agents e.g. prostaglandin E2 Factors that interacted with platelet receptors e.g. platelet activating factor which increase aggregation and factors that inhibited platelet activation e.g. Prostaglandin I2 and nitric oxide gained marks.

2009A 17: Pass rate: 40% Points required included a definition of PEEP, both intrinsic and extrinsic. The important physiological consequences that need to be discussed are respiratory including increased FRC, increased compliance and decreased work of breathing. Cardiovascular consequences include decreased venous return and subsequently decreased cardiac output and an increased pulmonary vascular resistance. Renal consequences include decreased renal blood flow and increased ADH Effects on intra-abdominal pressure, hepatic blood flow and the beneficial effects in cardiac failure earned marks. Syllabus B1k.2a Reference: Nunn 6th edition p. 431.9

2009A 18: Pass rate: 30% Important factors to be discussed in this answer were anatomical site, laminar versus turbulent flow, airway calibre and factors that affect it such as oedema and sympathetic tone. The effect of lung volume on airway resistance is usefully described in a diagram. The differences in infants earned extra marks Syllabus B1d, 2h Reference: Nunn 6th edition p39-47.

2009A 19: Pass rate: 40% Candidates were expected to list and briefly define the role of the various substances produced and secreted by the stomach. These included the hormones gastrin and somatostatin, the enzymes pepsin, lipase and gelatinase, the electrolytes Na+, K+ and HCO3- , HCl and water, prostaglandins and mucus, and intrinsic factor. For example: HCl secreted by parietal cells to produce a very acidic environment pH 1-3.5. This optimizes proteolytic activity of pepsin, has a direct proteolytic role, aids ferric iron conversion to the more soluble ferrous ion, and is important for bactericidal activity and innate immunity. It also stimulates pancreatic and biliary secretions. Good answers divided the functions into digestive, hormonal, mucosal protection, immunity etc. Marks were not gained for mention of the secretions of other GIT organs. SyllabusQ12b Reference: Guyton and Hall 11th edition p791-799

2009A 20: Pass rate: 40% Organophosphates (OGP) bind irreversibly to acetyl cholinesterase. They produce a cholinergic crisis and muscle paralysis due to excess Acetyl choline (ACh) at all muscarinic and nicotinic receptors. Candidates were required to discuss the pharmacology relevant to treating OGP poisoning, including active decontamination/staff protection due to high lipid solubility, use of antimuscarinics with central and peripheral action to treat cholinergic symptoms, supportive therapy for muscle weakness (there is no antinicotinic agent available which does not exacerbate muscle weakness), and finally the use of the cholinesterase regenerator, Pralidoxime, which may prevent the OGP-AChE complex ageing and becoming an irreversible bond if given in a timely fashion. Good answers included a discussion of the mechanism of action of the therapeutic agents, the time course of therapy, the large doses/infusions of atropine required and the titration of therapy to reversal of muscarinic effects. Long lists of signs and symptoms were not required to pass this question. Syllabus H2b2c Reference: Rang Dale Ritter 6th edition p 164-166, Katzung 10th edition p 116-117, 968.

2009A 21: Pass rate: 40% Good answers were in tabular format. The antidepressant action is similar for each agent. Initial increase in 5HT and NA, followed in 2-3 weeks by a down regulation or change in efficiency of 5HT transmission. The agents produce elevated neurotransmitters via different mechanisms, either reuptake blockade or enzyme inhibition. MAOIs can be competitive or non-competitive. Mention of the different neurotransmitters affected by each agent was required. A description of significant side effects at therapeutic doses, and in overdose was expected with explanations provided. These should have included - the anticholinergic effects and cardiotoxicity of TCAs, postural hypotension, the catecholamine, pethidine and tyramine related complications of MAOIs, and serotonin syndrome with SSRI/MAOI use and or overdose. More marks were gained for mention that side effect profiles can be beneficial e.g. analgesic properties of TCAs, sedation with TCAs/ SSRIs and energizing benefits of SSRIs/SNRIs. SSRI’s safety and efficacy have markedly reduced the use of MAOIs and to a lesser extent TCA’s.. Syllabus G2f2d Reference: Stoelting p 398-407, Katzung p 476-487.

2009A 22: Pass rate: 20% The answers to this question were generally not broad enough. Only one or two drugs were discussed rather than the range of drugs used in this situation. Discussion should have included benzodiazepines, intravenous induction agents, opioid narcotics, diuretics including loop diuretics and mannitol. Hypertonic saline also gained marks. Generally the discussions on the drugs mentioned were done well. Some candidates discussed the physiological control of intracranial pressure which was not required and gained no marks. Syllabus G2g, G2a2a E2a2a

2009A 23: Pass rate: 50% This answer was generally well done. Most answers showed good understanding of mechanism of action. The antibacterial spectrum and pharmacokinetics were done less well. Clinical observation guiding your study would help in answering this question, such as renal dosing, monitoring drug levels and situations in which aminoglycosides are used. Syllabus M2 2d Reference: Katzung 10th edition p 755-762

2009A 24: Pass rate: 30% Good answers showed an understanding of diffusion, the influence on transfer of lipid solubility, molecular size, degree of ionisation and protein binding. They also made reference to placental transporters and placental metabolism. Extra points were scored for mentioning that the real concern is teratogenicity to the foetus. Syllabus O2 2d Reference: Katzung 10th edition p 971-973. VIVAs A. Pharmaceutics B. Pharmacokinetics C. Pharmacodynamics pharmacokinetics in: Alcohol, Ageing D. Variability in Drug Response E. Cellular Physiology discuss cell membrane physiology and electrolyte disturbances. F. Respiratory Patient with PE. Calculate the A-a gradient. G. CVS action potential of the ventricle, sinus node and the atrioventricular node. It will also assess knowledge of anti-arrhythmic drugs H. Renal I. Body Fluids and Electrolytes J. Acid Base K. Neuro L. Musculoskeletal M. ANS N. Liver O. GIT P. Nutrition and Metabolism Q. Haematology Red Blood Cells and the Clark electrode R. Thermoregulation S. Immunology Outline the body’s defence mechanisms against infection T. Microbiology How do bacteria differ from the majority of normal human cells (eukaryotes)? Antimicrobial agents. U. Endocrine V. Obstetrics W. Measurement and Monitoring X. Procedures US image of Carotid, IJV - how can you distinguish the two