2021 First Sitting

2021A 02: 24% of candidates passed this question. This is a core topic within respiratory physiology. There was a very low pass rate for this question. Expected components of the answer included: a definition of WOB as a product of pressure and volume or force and distance including the units of measurement; followed by a detailed explanation of the following three broad components – elastic resistance, viscous resistance and airflow resistance. Further marks were awarded to situations where the energy for expiration increases beyond stored potential energy as well as the impact of respiratory rate and tidal volume on different aspects of the WOB. For example, the changes in TV will have relatively greater impact on the elastic component, whereas RR will impact the resistance component. Additional marks were awarded for describing the efficiency of breathing. A common area where candidates missed out on marks was producing a diagram of WOB without a description; many diagrams were often incorrectly drawn or had no axes labelled. There were many incorrect definitions or respiratory equations provided without any link to the written answer. Factual inaccuracy and limited depth of knowledge were also prevalent in poorly performing answers. Marks were not awarded for a description of the control of breathing.

2021A 03: 79% of candidates passed this question. This question was divided in three sections to help candidates formulate an answer template. The first section required a brief outline of the formation of platelets from pluripotent stem cells via megakaryocytes. The second section required an outline of platelet structure highlighting the special features such as, an absence of a nucleus, the presence of an external glycocalyx layer, specific surface receptors, contractile proteins, dense tubular system and granules. The third section was about platelet function where the expected focus was on the role of platelets in haemostasis. This required outlining the mechanism of platelet plug formation by adhesion-activation-aggregation, interactions with the coagulation cascade and role of platelets in clot contraction as well as fibroblast invasion. Although many candidates were able to answer the first section reasonably well, there was a noticeable knowledge deficit in the latter two sections. A significant proportion of answers had missing information on platelet structure and lack of structure in outlining platelet function.

2021A 04: 59% of candidates passed this question. The pharmacology of enteral and parenteral nutrition is a level 1 topic in the first part syllabus. The TPN dose in terms of daily calorie and other nutritional requirements were key expectations in first part of the question. A detailed list of all macro and micronutrients was required under TPN composition. Expected information about macronutrients were their forms in the TPN solution (e.g., carbohydrate in the form of glucose, protein in the form amino acids), their relative calorie contributions and their essential components (e.g., the names of the essential amino acids). Identification of potential variability in composition and dose based on specific patient factors scored extra marks. Side effects included metabolic derangements (refeeding syndrome, over or under-feeding, hyperglycaemia, hyperlipemia), biochemical disturbances (fluid and electrolyte imbalances), organ injury (liver, pancreas) and vascular access related complications. Limited breadth and depth of information as well as incorrect facts were prevalent in the answers that scored lower marks.

2021A 05: 57% of candidates passed this question. This question examined a core area of cardiac physiology and measurement. Considering this, candidates overall, scored poorly in this section. There was a common misunderstanding around the relationship between cardiac output and CVP. A decrease in cardiac output (e.g. due to either decreased stroke volume or heart rate) will cause an increase in CVP as blood backs up in the venous circulation, increasing venous volume as less blood moves through to the arterial circulation; the resultant increase in thoracic volume increases central venous pressure. Several candidates confused the direction of their arrows, for example “increased right atrial compliance increases CVP”. Double negatives were used by several candidates which then resulted in the incorrect relationship described. (e.g., “arrow down compliance and arrow down CVP”). The measurement section should have included an explanation of the components of an invasive pressure monitoring system relevant to the measurement of CVP.

2021A 06: 13% of candidates passed this question. Vecuronium is a commonly available and regularly used amino-steroid neuromuscular blocking agent. It is a level 1 drug in the 2017 syllabus. A simple template utilising the headings; pharmaceutics, PK, PD, uses in ICU and adverse reactions with associated relevant important facts would have scored well. Expected information regarding the factors prolonging neuromuscular blockade included electrolyte abnormalities, drug interactions and patient factors. Overall, the level of understanding and knowledge demonstrated in the answers was below an expected standard for a level 1 drug.

2021A 07: 48% of candidates passed this question. This question was answered best if the main arteries and veins were discussed first and then their corresponding supply outline in reasonable detail. Very few candidates were able to achieve this. Listing the names of vessels with no context and in a random non-sequential order did not attract many marks. The physiology of the blood supply to the liver also did not attract marks.

2021A 08: 33% of candidates passed this question. This question covers a core physiology topic. The detail required is well described in the recommended reference texts. Generally, this question was poorly answered. From an answer template perspective, a "describe question" in this context involves both the stating the relevant potassium handling mechanism and then giving a description of how it occurs and how this system is regulated. Many answers that scored poorly simply listed sites of potassium handling but excluded the details surrounding the specific receptors and channels involved as well as the processes that exist to perpetuate and regulate these biological processes. Simple identification as to whether the potassium was being secreted or reabsorbed as well as the location as to where this may occur within the nephron, were often not specifically detailed or used interchangeably. Such answers scored poorly.

2021A 09: 59% of candidates passed this question. This question was relatively well answered by most candidates. There was significant variation in the temperatures expressed as normal and few candidates mentioned CORE temperature as a concept. Several candidates gave a detailed description of thermo-neutrality for which there were no marks.

2021A 10: 43% of candidates passed this question. Warfarin is listed as a level 1 drug in the 2017 syllabus and as such a detailed knowledge of its mechanism of action would be expected from candidates sitting the exam. The reversal agents for warfarin are collectively classed as level 2 drugs and hence the knowledge required would be at a write short notes level. The following topics were expected: what drugs may be used, how they work, in what dose, any common side effects, why/when would one be used in preference to others etc. The use of reversal agents for warfarin is a common practice in ICU. Generally, answers demonstrated a lack of a precise and detailed knowledge with respect to warfarin’s mechanism of action and had a very superficial knowledge with incorrect facts regarding the reversal agents.

2021A 11: 57% of candidates passed this question. This is a core physiology topic; a detailed knowledge of buffering and the available buffer systems is crucial to ICU practice. A candidate presenting for the first part exam should have a detailed understanding of all aspects of the buffer systems. Higher scoring answers provided both technical details of the buffer systems, the context for their normal function and their relative importance. Efficient answers dealt with the buffers by chemical rather than by site, but many answers categorising buffers by site also scored well. Many low scoring answers simply failed to provide detail, some provided incorrect information. Very few candidates demonstrated an understanding of the isohydric principle.

2021A 13: 40% of candidates passed this question. Few candidates described cell types as chromophils and chromophobes. There were many errant references to chromaffin cells which are found mainly in the adrenal medulla, and to staining on H&E. Chromophil cells stain by absorbing chromium salts. Few candidates mentioned that the hormones secreted by the anterior pituitary are peptides. Most candidates outlined the hypophyseal-portal system well. Knowledge of TSH and ACTH control and target organ effects were good. Similar knowledge for LH, FSH, PRL and GH was much more sporadic.

2021A 15: 36% of candidates passed this question. This question required detail on those factors affecting gas exchange at the level of the alveolus. A description of the components of the Fick equation was expected – and how this related to oxygen and carbon dioxide transfer at the alveolar capillary membrane. The rapid rate of equilibration (developed tension) was the limiting factor in of blood/alveolar exchange that rendered some gases perfusion limited (examples – N2O, O2 under usual conditions but not all) and the slower rate of others diffusion limited (examples CO and O2 under extreme conditions e.g., exercise, altitude). Estimates of time taken for each gas to equilibrate relative to the time taken for the RBC to travel across the interface was also expected for full marks. CO2 despite rapid equilibration and higher solubility was correctly described as perfusion limited (unless in disease states). Better answers described CO2 as ventilation limited. Some answers also correctly included the component of interaction with the RBC and haemoglobin. Ventilation/perfusion inequalities over the whole lung were not asked for and scored no marks.

2021A 17: 74% of candidates passed this question. Most candidates provided a reasonable structured sequence of how a pulse oximeter generates a value. Nearly all candidates described the Beer-Lambert laws correctly, but few specifically described the basic principles of absorption spectrophotometry. Most candidates had a reasonable list of extrinsic factors that can interfere with pulse oximeter performance, but few described the intrinsic/inherent limitations of the device that can cause SpO2 to be different to SaO2, such as functional versus fractional saturation.

2021A 19: 62% of candidates passed this question. Good candidates described normal blood flow to the coronary circulation, including differences between the right and left ventricles. Coronary artery anatomy was outlined, including the regions of the heart supplied and the concept of dominance. In addition to epicardial vessels, strong answers also outlined penetrating arteries, subendocardial supply and venous drainage. Regulation of coronary blood flow required an explanation of flow-dependence of the heart given its high oxygen extraction rate. Metabolic autoregulation and its mediators needed to be described, along with the physical factors driving coronary blood flow. Less important mechanisms such as the role of the autonomic nervous system were also described, with an emphasis on indirect effects over direct effects.

2021A 20: 19% of candidates passed this question. Overall, this question was poorly answered with a high failure rate. A good answer gave a normal value, iterated that CBF is held relatively constant by autoregulation, and proceeded to divide factors affecting CBF into categories with an explanation/description of each. Those factors with the greatest influence were expected to have more accompanying information (e.g., pressure/myogenic autoregulation, metabolic). Systemic factors such as MAP, O2, CO2 were expected to be mentioned with detail of the impact (i.e., key values, relationships demonstrated with a description and/or labelled graph). Local factors within the brain such as H+ concentration/pH, metabolic activity (including the impact of temperature, inclusion of mediators, regional variation based on activity & grey versus white matter) were also expected to be mentioned. Few answers mentioned impact of pH change independently of CO2. Few answers mentioned how CO2 changes the pH of CSF and that over time, this impact is buffered/reduces. The role of the sympathetic nervous system was required to be mentioned although not explored in detail (although many answers overstated the importance of the SNS on CBF or gave a simplistic concept such as increased SNS activity increases CBF). Many answers focussed on descriptions of the Monro-Kelly doctrine and ICP to the exclusion of the aforementioned factors or included detail on factors influencing MAP which were not required (and irrelevant when within the autoregulation range). Many answers were simplistic: e.g., increase MAP increase CPP therefore increase CBF, or by stating CO2/O2 without mentioning a relationship or the limits/patterns of the relationship. Many answers failed to separate the effect of systemic PaO2 and PaCO2 from metabolic autoregulation. VIVAs A. Pharmaceutics B. Pharmacokinetics C. Pharmacodynamics D. Variability in Drug Response E. Cellular Physiology F. Respiratory Compliance Measurement: Concentration of oxygen in inspired gas Oxygen cascade: Steps and values Oxygen delivery devices CO2 carriage, physiology G. CVS Invasive arterial monitoring systems, improve accuracy MeasurementL CO, SVR Baroreceptor reflexes, rapid onset hypovolemia (20% blood volume loss over 10 mins) Arterial waveform: label, what determines shape of waveform H. Renal Principles of haemodialysis I. Body Fluids and Electrolytes IVF, effects. Large volume (2-3L) infusion NS Blood plasma and non-protein components J. Acid Base Acid, how much produced daily ABG interpretation (pH 7.4 BE -20 HCO# 8 Na 145 K 4.4 Cl 113) K. Neuro Cranial neve anatomy, pupillary reflex Propofol pharmacology. What is in a bottle of propofol Opioid pharmacology, MoA L. Musculoskeletal End plate potential generation, how is it different from miniature end plate potential, NM transmission and monitoring M. ANS N. Liver Functional unit of liver. Label structures, significance of arrangement O. GIT Nausea and Vomiting. Sequential muscle contractions during vomiting P. Nutrition and Metabolism Q. Haematology Blood groups and determination Viscoelastic measurement of coagulation, information obtained. Anti-platelet pharmacology R. Thermoregulation S. Immunology T. Microbiology U. Endocrine Glucose storage, physiology, pharmacology V. Obstetrics Maternofoetal physiology. Normal ABG at term. Explain changes. ABG: pH 7.45 pO2 105 pCO2 30 HCO3 20 BE -2 W. Measurement and Monitoring X. Procedures