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  • Question 1 - Which of the following is correct for gas pipeline pressure? ...

    Correct

    • Which of the following is correct for gas pipeline pressure?

      Your Answer: 4 bar for oxygen

      Explanation:

      Pipeline gases (in the UK this includes: Oxygen, Nitrous oxide, Medical air, and Entonox) are supplied at 4 bar (or 400 kPa), and compressed air is supplied at 7 bar for power tools.

      Carbon dioxide and nitric oxide are usually only supplied in cylinders.

    • This question is part of the following fields:

      • Anaesthesia Related Apparatus
      7.2
      Seconds
  • Question 2 - A 72-year-old long-term rheumatoid arthritis patient is having shoulder replacement surgery. He has...

    Incorrect

    • A 72-year-old long-term rheumatoid arthritis patient is having shoulder replacement surgery. He has chronic obstructive pulmonary disease with a limited exercise tolerance. He agrees to the procedure being performed with an interscalene brachial plexus block. Which of the following neurological complications puts this patient at the greatest risk?

      Your Answer: Cranial nerve X and XII block

      Correct Answer: Phrenic nerve block

      Explanation:

      An ipsilateral phrenic nerve block will result from a successful interscalene block (ISB).

      The phrenic nerve is the diaphragm’s sole motor supply, and ipsilateral hemidiaphragmatic paresis affects up to 100% of patients who receive ISBs. Phrenic nerve palsy is usually well tolerated and goes unnoticed by healthy people. However, forced vital capacity decreases by approximately 25%, which can produce ventilatory compromise in patients with limited pulmonary reserve, requiring assisted ventilation.

      Vocal cord palsy occurs when the recurrent laryngeal nerve is inadvertently blocked, causing hoarseness and possibly acute respiratory insufficiency. Unless bilateral laryngeal nerve palsy occurs, which can cause severe laryngeal obstruction, this complication is usually of little consequence.

      ISB can also cause cranial nerve X and XII palsy (Tapia’s syndrome). One-sided cord paralysis, aphonia, and the patient’s tongue deviating toward the block’s side are all symptoms.

      When a local anaesthetic spreads to the stellate ganglion and its cervical sympathetic nerves, Horner’s syndrome can develop. Ptosis of the eyelid, miosis, and anhidrosis of the face are all symptoms. Horner’s syndrome, on the other hand, may not indicate that the brachial plexus is sufficiently blocked.

    • This question is part of the following fields:

      • Pathophysiology
      38.5
      Seconds
  • Question 3 - The tip of a pulmonary artery flotation catheter becomes wedged when threaded through...

    Correct

    • The tip of a pulmonary artery flotation catheter becomes wedged when threaded through the chambers of the heart and the pulmonary artery. Which of the following options best describes the sequence of pressures measured at the catheter's tip during its passage through a normal patient's pulmonary artery?

      Your Answer: 0-12 mmHg, 2-25 mmHg, 12-25 mmHg and 8-12 mmHg

      Explanation:

      The tricuspid valve allows the tip of a pulmonary artery catheter to pass through the right atrium and into the right ventricle.

      The balloon will be inflated before crossing the pulmonary valve and entering the pulmonary artery, where it will eventually wedge or occlude the artery, providing an indirect measure of left atrial pressure.

      0-12 mmHg in the right atrium
      2-25 mmHg in the right ventricle
      12-25 mmHg in the pulmonary artery
      8-12 mmHg is the occlusion pressure

    • This question is part of the following fields:

      • Physiology And Biochemistry
      24.7
      Seconds
  • Question 4 - Which of the following statements about closing capacity is true? ...

    Incorrect

    • Which of the following statements about closing capacity is true?

      Your Answer: It decreases with age

      Correct Answer: It is less than the functional residual capacity in a 30-year-old

      Explanation:

      Closing capacity refers to volume of gas within the lungs at which the conducting small airways begin to close, that is, the point during expiration when small airways close.

      It is calculated mathematically as:

      Closing capacity = Closing volume (CV) + Residual volume (RV)

      Functional residual capacity (FRC) is the volume of gas still present within the lungs post expiration.

      Closing capacity is lower than the functional residual capacity in younger adults, but begins to rise to eventually equal, and then exceed it with increasing age (at about middle age), increasing intrabdominal pressure, decreasing blood flow in the pulmonary system and parenchymal disease within the pulmonary system.

    • This question is part of the following fields:

      • Clinical Measurement
      20.4
      Seconds
  • Question 5 - The thyroid gland: ...

    Correct

    • The thyroid gland:

      Your Answer: Internalises iodine through active transport

      Explanation:

      The thyroid gland is a gland shaped like a butterfly which lies at the base of the anterior neck. It controls metabolism using hormone secretion.

      Iodine is extremely important for the synthesis of hormones within the thyroid. It is internalised into the thyroid follicular cells via the sodium/iodide symporter (NIS).

      The parathyroid glands are found posterior to the thyroid gland, with the recurrent laryngeal nerves running posteromedially.

      The expected weight of a normal thyroid gland is about 30 grams.

    • This question is part of the following fields:

      • Pathophysiology
      14.3
      Seconds
  • Question 6 - A 25 year-old female came to the out-patient department with complaints of vaginal...

    Incorrect

    • A 25 year-old female came to the out-patient department with complaints of vaginal discharge with a distinct fishy odour. She was later diagnosed with bacterial vaginosis and was prescribed to take metronidazole. The mechanism of action of metronidazole is?

      Your Answer: Interferes with bacterial protein synthesis

      Correct Answer: Interferes with bacterial DNA synthesis

      Explanation:

      Metronidazole is a nitroimidazole antiprotozoal drug that is selectively absorbed by anaerobic bacteria and sensitive protozoa. Once taken up be anaerobes, it is nonenzymatically reduced by reacting with reduced ferredoxin. This reduction results in products that accumulate in and are toxic to anaerobic cells. The metabolites of metronidazole are taken up into bacterial DNA, forming unstable molecules. This action occurs only when metronidazole is partially reduced, and, because this reduction usually happens only in anaerobic cells, it has relatively little effect on human cells or aerobic bacteria.

    • This question is part of the following fields:

      • Pharmacology
      36.6
      Seconds
  • Question 7 - Regarding the following induction agents, which one is cleared at the fastest rate...

    Incorrect

    • Regarding the following induction agents, which one is cleared at the fastest rate from the plasma?

      Your Answer: Methohexitone

      Correct Answer: Propofol

      Explanation:

      Propofol is cleared at the fastest rate at the rate of 60ml/kg/min.

      Clearance rate of other drugs are as follows:
      – Thiopental: 3.5 ml/kg/min
      – Methohexitone: 11 ml/kg/min
      – Ketamine: 17 ml/kg/min
      – Etomidate: 10-20 ml/kg/min

    • This question is part of the following fields:

      • Pharmacology
      14.6
      Seconds
  • Question 8 - An older woman has been brought into the emergency department with symptoms of...

    Correct

    • An older woman has been brought into the emergency department with symptoms of a stroke. A CT angiogram is performed for diagnosis, which displays narrowing in the artery that supplies the right common carotid. Which of the following artery is the cause of stroke in this patient?

      Your Answer: Brachiocephalic artery

      Explanation:

      The arch of aorta gives rise to three main branches:
      1. Brachiocephalic artery
      2. Left common carotid artery
      3. Left subclavian artery

      The brachiocephalic artery then gives rise to the right subclavian artery and the right common carotid artery.

      The right common carotid artery arises from the brachiocephalic trunk posterior to the sternoclavicular joint.

      The coeliac trunk is a branch of the abdominal aorta.
      The ascending aorta supplies the coronary arteries.

    • This question is part of the following fields:

      • Anatomy
      14.4
      Seconds
  • Question 9 - Which one of the following factor affects the minimal alveolar concentration (MAC)? ...

    Correct

    • Which one of the following factor affects the minimal alveolar concentration (MAC)?

      Your Answer: Hypoxaemia

      Explanation:

      The minimal alveolar concentration (MAC) is the concentration of an inhalation anaesthetic agent in the lung alveoli required to stop a response to the surgical stimulus in 50% of the patient.

      Following factors don’t affect the MAC of the inhaled anaesthetic agents:

      Gender, acidosis, alkalosis, hypothyroidism, hyperthyroidism, body weight, serum potassium level, and the duration of the anaesthesia.

      MAC increase in children, elevated temperature, high metabolic rate, sympathetic increase and chronic alcoholism.

      MAC decrease in low temperature, low oxygen level, old age, hypotension ( 120mmHg is being used in anesthetic-Hinkman as an additive effect to decrease MAC, however, increase concentration of CO2 activates the sympathetic system resulting the MAC increases.

    • This question is part of the following fields:

      • Physiology
      20.9
      Seconds
  • Question 10 - Venepuncture is being performed on the basilic vein in the cubital fossa. At...

    Incorrect

    • Venepuncture is being performed on the basilic vein in the cubital fossa. At which of the following points does the basilic vein pass deep under the muscle?

      Your Answer: At the axilla

      Correct Answer: Midway up the humerus

      Explanation:

      The basilic vein is one of the primary veins that drain the upper limb, like the cephalic vein. It begins as the dorsal venous arch. The basilic vein originates from the ulnar side of the dorsal arch of the upper limb passes along the posteromedial aspect of the forearm, moving towards the anterior surface of the elbow.

      The basilic vein pierces the deep fascia at the elbow and joins the venae commitantes of the brachial vein to form the axillary vein.

      The basilic vein passes deep under the muscles as it moves midway up the humerus. At the lower border of the teres major muscle, the anterior and posterior circumflex humeral veins feed into it.

    • This question is part of the following fields:

      • Anatomy
      42.4
      Seconds
  • Question 11 - Ondansetron is serotonin antagonist indicated for post-operative nausea and vomiting. In which of...

    Correct

    • Ondansetron is serotonin antagonist indicated for post-operative nausea and vomiting. In which of the following anatomic structures does ondansetron produce its effects?

      Your Answer: Nucleus tractus solitarius

      Explanation:

      Ondansetron is a serotonin antagonist at the 5HT3 receptor. 5HT3 receptors in the gastrointestinal tract and in the vomiting centre of the medulla participate in the vomiting reflex. They are particularly important in vomiting caused by chemical triggers such as cancer chemotherapy drugs.

      The nucleus solitarius is the recipient of all visceral afferents, and an essential part of the regulatory centres of the internal homeostasis, through its multiple projections with cardiorespiratory and gastrointestinal regulatory centres. It participates in the reflexes of the nerves innervating the nucleus, so it mediates cough reflex, carotid sinus reflex, gag reflex, and vomiting reflex.

    • This question is part of the following fields:

      • Pharmacology
      10.3
      Seconds
  • Question 12 - A 24-year-old female, presents to the emergency department via ambulance. She has just...

    Correct

    • A 24-year-old female, presents to the emergency department via ambulance. She has just been involved in a car accident. She is examined and undergoes various diagnostic investigations. Her X-ray report states that a fracture was noted on the surgical neck of her humerus. What structure is most likely to the damaged as a result of a surgical neck fracture of the humerus?

      Your Answer: Axillary nerve

      Explanation:

      Fractures to the surgical neck of the humerus are common place as it is the weakest point of the proximal humerus bone.

      The structures most likely to be damaged are the axillary nerve and the posterior circumflex humeral artery as they surround the surgical neck.

      The radial nerve runs along the radial groove, so injury to it would likely occur with a mid-shaft fracture of the humerus.

      The brachial artery is most likely to be injured as a result of a supracondylar fracture of the humerus which increases the risk of volkmaan’s ischemic contractures.

      Injury to the musculocutaneous nerve is least likely to happen and it very uncommon.

    • This question is part of the following fields:

      • Anatomy
      18.1
      Seconds
  • Question 13 - Regarding adrenocorticotropic hormone (ACTH) one of these is true. ...

    Correct

    • Regarding adrenocorticotropic hormone (ACTH) one of these is true.

      Your Answer: Is increased in the maternal plasma in pregnancy

      Explanation:

      ACTH production is stimulated through the secretion of corticotropin-releasing hormone (CRH) from the hypothalamic nuclei.

      ACTH secretion has a circadian rhythm. A high level of cortisol in the body stops its production. ACTH is secreted maximally in the morning and concentrations are lowest at midnight.

      ACTH can be expressed in the placenta, the pituitary and other tissues.

      Conditions where ACTH concentrations rise include: stress, disease and pregnancy.

      Glucocorticoids (not mineralocorticoids – aldosterone) switch off ACTH production through a negative feedback loop .

    • This question is part of the following fields:

      • Pathophysiology
      34
      Seconds
  • Question 14 - A 50-year old female came to the Obstetric and Gynaecology department for an...

    Correct

    • A 50-year old female came to the Obstetric and Gynaecology department for an elective hysterectomy under general anaesthesia. Upon physical examination, she was noted to be obese (BMI = 40). Regarding the optimal dose of thiopentone, which of the following parameters must be considered for the computation?

      Your Answer: Lean body weight

      Explanation:

      Using a lean body weight metric encompasses a more scientific approach to weight-based dosing. Lean body weight reflects the weight of all €˜non-fat’ body components, including muscle and vascular organs such as the liver and kidneys. As lean body weight contributes to approximately 99% of a drug’s clearance, it is useful for guiding dosing in obesity.

      This metric has undergone a number of transformations. The most commonly cited formula derived by Cheymol is not optimal for dosing across body compositions and can even produce a negative result. A new formula has been developed that appears stable across different body sizes, in particular the obese to morbidly obese.

      A practical downfall of the calculation of lean body weight (and other body size descriptors) is the numerical complexity, which may not be palatable to a busy clinician. Often limited time is available for prescribing and an immediate calculation is required. Lean body weight calculators are available online, for example in the Therapeutic Guidelines.

      Using total body weight assumes that the pharmacokinetics of the drug are linearly scalable from normal-weight patients to those who are obese. This is inaccurate. For example, we cannot assume that a 150 kg patient eliminates a drug twice as fast as a 75 kg patient and therefore double the dose. Clinicians are alert to toxicities with higher doses, for example nephro- and neurotoxicity with some antibiotics and chemotherapeutics, and bleeding with anticoagulants. Arbitrary dose reductions or €˜caps’ are used to avoid these toxicities, but if too low can result in sub-therapeutic exposure and treatment failure.

      Body surface area is traditionally used to dose chemotherapeutics. It is a function of weight and height and has been shown to correlate with cardiac output, blood volume and renal function. However, it is controversial in patients at extremes of size because it does not account for varying body compositions. As a consequence, some older drugs such as cyclophosphamide, paclitaxel and doxorubicin were €˜capped’ (commonly at 2 m^2) potentially resulting in sub-therapeutic treatment. Recent guidelines suggest that unless there is a justifiable reason to reduce the dose (e.g. renal disease), total body weight should be used in the calculation of body surface area, until further research is done. Little research into dosing based on body surface area has been conducted for other medicines.

      Ideal body weight was developed for insurance purposes not for drug dosing. It is a function of height and gender only and, like body surface area, does not take into account body composition. Using ideal body weight, all patients of the same height and sex would receive the same dose, which is inadequate and generally results in under-dosing. For example a male who has a total body weight of 150 kg and a height of 170 cm will have the same ideal body weight as a male who is 80 kg and 170 cm tall. Both could potentially receive a mg/kg dose based on 65 kg (ideal body weight).

    • This question is part of the following fields:

      • Pharmacology
      16.1
      Seconds
  • Question 15 - All of the following are causes of hypalbuminaemia except: ...

    Correct

    • All of the following are causes of hypalbuminaemia except:

      Your Answer: Starvation

      Explanation:

      Major surgery induces the systemic inflammatory response and this causes endothelial leakage and a low albumin level.

      Albumin is a single polypeptide which is made but not stored in the liver. Therefore, levels are a reflection of synthetic activity. It is negatively charged and very soluble.

      Only 40% of albumin is intravascular, and the rest in the in interstitial compartment.

      If there was normal liver function during starvation, albumin will be maintained and proteolysis will occur elsewhere.
      It is not catabolised during starvation.
      Starvation and malnutrition may, however, present as part of other disease processes that are associated with hypalbuminaemia.

      Causes of low albumin are

      1. Decreased production (hepatic dysfunction)
      2. Increased loss (renal dysfunction)
      3. Redistribution (endothelial leak/damage)
      4. Increased catabolism (very rare)

    • This question is part of the following fields:

      • Physiology And Biochemistry
      28.7
      Seconds
  • Question 16 - With regards to the internal carotid artery, which of these statements is correct....

    Correct

    • With regards to the internal carotid artery, which of these statements is correct.

      Your Answer: Enters the skull and divides into the anterior and middle cerebral arteries

      Explanation:

      The internal carotid artery passes through the carotid canal in the petrous part of the temporal bone into the cranial cavity. It does NOT groove the sphenoid bone.

      The internal carotid artery gives off no branches in the neck and is a terminal branch of the common carotid artery.

      These structures pass between the external and internal carotid arteries: the styloglossus and stylopharyngeus muscles, the glossopharyngeal nerve (CN IX), and the pharyngeal branch of the vagus.

      Accompanied by its sympathetic plexus, the internal carotid artery, passes through the cavernous sinus and is crossed by the abducent nerve.

    • This question is part of the following fields:

      • Anatomy
      23
      Seconds
  • Question 17 - A 45-year-old woman complains of pain in her upper abdomen to her physician....

    Correct

    • A 45-year-old woman complains of pain in her upper abdomen to her physician. The pain comes intermittently in waves and gets worse after eating food. There are no associated complaints of fever or bowel problems. The pain intensity is 6/10, and paracetamol relieves it a little. There is suspicion that part of the biliary tree is blocked. Which area of the duodenum does this blocked tube open into?

      Your Answer: 2nd part of the duodenum

      Explanation:

      The patient is likely suffering from biliary colic since her pain is intermittent and comes and goes in waves. Biliary colic pain gets worse after eating, especially fatty food as bile helps digest fats. Gallstones are the most common cause of biliary colic and are usually located in the cystic duct or common bile duct. But since this patient has no signs of jaundice or steatorrhea, the duct most likely blocked is the cystic duct.

      The cystic duct drains the gallbladder and combines with the common hepatic duct to form the common bile duct. The common bile duct then merges with the pancreatic duct and opens into the second part of the duodenum (major duodenal papilla).

      The duodenojejunal flexure is attached to the diaphragm by the ligament of Treitz and is not associated with any common pathology.
      The fourth part of the duodenum passes very close to the abdominal aorta and can be compressed by an abdominal aortic aneurysm.
      The third part of the duodenum can be affected by superior mesenteric artery syndrome, where the duodenum is compressed between the SMA and the aorta, often in cases of reduced body fat.
      The first part of the duodenum is the most common location for peptic ulcers affecting this organ.

    • This question is part of the following fields:

      • Anatomy
      13.1
      Seconds
  • Question 18 - A controlled retrospective study's level of evidence is? ...

    Incorrect

    • A controlled retrospective study's level of evidence is?

      Your Answer: Level 2

      Correct Answer: Level 3

      Explanation:

      Level 1 – High-quality randomised controlled trial with statistically significant difference or no statistically significant difference but narrow confidence intervals (prospective controlled)

      Level 2 – Prospective comparative study (prospective uncontrolled)

      Level 3 – Case-control study, retrospective comparative study (retrospective controlled)

      Level 4 – Case series (retrospective uncontrolled)

      Level 5 – Expert opinion.

    • This question is part of the following fields:

      • Statistical Methods
      8.7
      Seconds
  • Question 19 - A patient is being prepped for major bowel surgery. Alice, a final-year medical...

    Correct

    • A patient is being prepped for major bowel surgery. Alice, a final-year medical student, observes the surgery but is asked to scrub in and assist the anaesthetist during intubation. The anaesthetist inserts the laryngoscope and asks Alex to locate the larynx. What anatomical landmark corresponds to the position of the larynx?

      Your Answer: C3-C6

      Explanation:

      The larynx is an air passage, sphincter, and organ of phonation that extends from the tongue to the trachea. It lies in the anterior part of the neck at the vertebral levels C3 to C6.

      Important anatomical landmarks:
      C1-C2 – Atlas and axis, respectively

      C3-C6 – Larynx

      C5 – Thyroid cartilage

      T5-T7 – Pulmonary hilum

      T12-L1 – Duodenum.

    • This question is part of the following fields:

      • Anatomy
      16.8
      Seconds
  • Question 20 - A 68-year old female is brought to the Emergency Room for abdominal pain....

    Correct

    • A 68-year old female is brought to the Emergency Room for abdominal pain. Medical history revealed that she is on long-term warfarin therapy for deep vein thrombosis. Upon further investigation, the patient is hypotensive at 80/60 mmHg, and an abdominal mass is palpable on the umbilical area. An initial diagnosis of ruptured abdominal aortic aneurysm (AAA) is made. Moreover, blood tests show an international normalised ratio (INR) of 4.2. Which of the following products should be initially transfused or administered to the patient to reverse the anticoagulation?

      Your Answer: Prothrombin complex

      Explanation:

      Warfarin prevents reductive metabolism of the inactive vitamin K epoxide back to its active hydroquinone form. Thus, warfarin inhibits the synthesis of vitamin K dependent clotting factors: X, IX, VII, II (prothrombin), and of the anticoagulants protein C and protein S. The therapeutic range for oral anticoagulant therapy is defined in terms of an international normalized ratio (INR). The INR is the prothrombin time ratio (patient prothrombin time/mean of normal prothrombin time for lab)ISI, where the ISI exponent refers to the International Sensitivity Index and is dependent on the specific reagents and instruments used for the determination. A prolonged INR is widely used as an indication of integrity of the coagulation system in liver disease and other disorders, it has been validated only in patients in steady state on chronic warfarin therapy.

      Prothrombin complex concentrate (PCC) is used to replace congenital or acquired vitamin-K deficiency warfarin-induced anticoagulant effect, particularly in the emergent setting.

      Intravenous vitamin K has a slower onset of action compared to PCC, but is useful for long term therapy.

      Fresh frozen plasma (FFP) prepared from freshly donated blood is the usual source of the vitamin K-dependent factors and is the only source of factor V. The factors needed, however, are found in small quantities compared to PCC.

      Cryoprecipitate is indicated for hypofibrinogenemia/dysfibrinogenemia, von Willebrand disease, haemophilia A, factor XIII deficiency, and management of bleeding related to thrombolytic therapy.

    • This question is part of the following fields:

      • Pathophysiology
      31.7
      Seconds
  • Question 21 - Which of the following statements is true about the in-hospital management of ventricular...

    Correct

    • Which of the following statements is true about the in-hospital management of ventricular fibrillation?

      Your Answer: Amiodarone may be administered following a third DC shock

      Explanation:

      Ventricular fibrillation (VT) is an arrhythmia caused by a distortion in the organized contraction of the ventricles leading to an inability to pump blood out into the body.

      Amiodarone is an anti arrhythmic drug used for the treatment of ventricular and atrial fibrillations. It is the gold standard of treatment for refractory pulseless ventricular tachycardia (VT) and ventricular fibrillation (VF).

      Guidelines for emergency treatment state that only the rescuer carrying out chest compressions on the patient may stand near the defibrillator as it charges.

      Cardio-pulmonary resuscitation (CPR) during cardiac arrest is required for 2 minute cycles.

      Hypovolaemia is as a cause of pulseless electrical activity (PEA) can be reversed using fluid resuscitation, whereas hypotension during cardiac arrest is either persistent or undetectable and is therefore irreversible.

      Hyperkalaemia and hypocalcaemia are treated using calcium salts, but calcium chloride is often preferred over calcium gluconate.

      During a pulseless VT or VF, a single precordial thump will be effective if administered within the first seconds of the occurrence of a shockable rhythm.

    • This question is part of the following fields:

      • Pathophysiology
      35.4
      Seconds
  • Question 22 - Left ventricular afterload is mostly calculated from systemic vascular resistance. Which one of...

    Incorrect

    • Left ventricular afterload is mostly calculated from systemic vascular resistance. Which one of the following factors has most impact on systemic vascular resistance?

      Your Answer: Pre-capillary arterioles

      Correct Answer: Small arterioles

      Explanation:

      Systemic vascular resistance (SVR), also known as total peripheral resistance (TPR), is the amount of force exerted on circulating blood by the vasculature of the body. Three factors determine the force: the length of the blood vessels in the body, the diameter of the vessels, and the viscosity of the blood within them. The most important factor that determines the systemic vascular resistance (SVR) is the tone of the small arterioles.

      These are otherwise known as resistance arterioles. Their diameter ranges between 100 and 450 µm. Smaller resistance vessels, less than 100 µm in diameter (pre-capillary arterioles), play a less significant role in determining SVR. They are subject to autoregulation.

      Any change in the viscosity of blood and therefore flow (such as due to a change in haematocrit) might also have a small effect on the measured vascular resistance.

      Changes of blood temperature can also affect blood rheology and therefore flow through resistance vessels.

      Systemic vascular resistance (SVR) is measured in dynes·s·cm-5

      It can be calculated from the following equation:

      SVR = (mean arterial pressure ˆ’ mean right atrial pressure) × 80 cardiac output

    • This question is part of the following fields:

      • Physiology
      36.1
      Seconds
  • Question 23 - In reference to confounding variables, which among the given is not true? ...

    Incorrect

    • In reference to confounding variables, which among the given is not true?

      Your Answer: Age and sex are common confounders

      Correct Answer: In the analytic stage of a study confounding can be controlled for by randomisation

      Explanation:

      Randomisation can be used to provide control over the confounding variables during the design stage of a study however during analytical stage a technique called stratification is used for controlling confounding variables. Since the question asks for the information that is factually incorrect.

    • This question is part of the following fields:

      • Statistical Methods
      34.8
      Seconds
  • Question 24 - Lisa is a 75-year-old female rushed into the emergency department by first-aid responders....

    Correct

    • Lisa is a 75-year-old female rushed into the emergency department by first-aid responders. The ambulance team give a history of vomiting, homonymous hemianopia, weakness of the left upper and lower limb, and dysphasia. Lisa adds that she has a headache that keeps worsening. Lisa takes Warfarin as she is a known case of atrial fibrillation. Her INR is 4.3 despite the ideal target being 2-3. CT scan of the head suggests anterior cerebral artery haemorrhage. What areas of the brain are affected by an anterior cerebral artery stroke?

      Your Answer: Frontal and parietal lobes

      Explanation:

      The anterior cerebral artery supplies the midline portion of the frontal lobe and the superior medial parietal lobe of the brain. It also supplies the front four-fifths of the corpus callosum and provides blood to deep structures such as the anterior limb of the internal capsule, part of the caudate nucleus, and the anterior part of the globus pallidus.

      The cerebral hemispheres are supplied by arteries that make up the Circle of Willis. The Circle of Willis is formed by the anastomosis of the two internal carotid arteries and two vertebral arteries.

      Clinically, the internal carotid arteries and their branches are often referred to as the anterior circulation of the brain. The anterior cerebral arteries are connected by the anterior communicating artery. Near their termination, the internal carotid arteries are joined to the posterior cerebral arteries by the posterior communicating arteries, completing the cerebral arterial circle around the interpeduncular fossa, the deep depression on the inferior surface of the midbrain between the cerebral peduncles.

      The middle cerebral artery supplies part of the frontal, temporal and parietal lobes.

      The posterior cerebral artery supplies the occipital lobe.

    • This question is part of the following fields:

      • Anatomy
      55.3
      Seconds
  • Question 25 - Prior to an urgent appendicectomy, a 49-year-old man requires a rapid sequence induction....

    Correct

    • Prior to an urgent appendicectomy, a 49-year-old man requires a rapid sequence induction. His BMI is equal to 50. Which of the following formulas is the most appropriate for calculating a suxamethonium dose in order to achieve optimal intubating conditions?

      Your Answer: 1-1.5 × actual body weight (mg)

      Explanation:

      The usual method of calculating the dose of a drug to be given to patients of normal weight is to use total body weight (TBW). This is because the lean body weight (LBW) and ideal body weight (IBW) dosing scalars are similar in these patients.

      Because the LBW and fat mass do not increase in proportion in patients with morbid obesity, this is not the case. Drugs that are lipid soluble, such as propofol or thiopentone, can cause a relative overdose. Lean body mass is a better scalar in these situations.

      Suxamethonium has a small volume of distribution, so the dose is best calculated using the TBW to ensure optimal and deep intubating conditions. The higher dose was justified because these patients’ plasma cholinesterase activity was elevated.

      Other scalars include:

      The dose of highly lipid soluble drugs like benzodiazepines, thiopentone, and propofol can be calculated using lean body weight (LBW). The formula LBW = IBW + 20% can be used on occasion.

      Fentanyl, rocuronium, atracurium, vecuronium, morphine, paracetamol, bupivacaine, and lidocaine are all administered with LBW.

      Formulas can be used to calculate the ideal body weight (IBW). There are a number of drawbacks, including the fact that patients of the same height receive the same dose, and the formulae do not account for changes in body composition associated with obesity. Because IBW is typically lower than LBW, administering a drug based on IBW may result in underdosing. The body mass index (BMI) isn’t used to calculate drug dosage directly.

    • This question is part of the following fields:

      • Pharmacology
      15.6
      Seconds
  • Question 26 - Standard error of the mean can be defined as: ...

    Correct

    • Standard error of the mean can be defined as:

      Your Answer: Standard deviation / square root (number of patients)

      Explanation:

      The standard error of the mean (SEM) is a measure of the spread expected for the mean of the observations – i.e. how ‘accurate’ the calculated sample mean is from the true population mean. The relationship between the standard error of the mean and the standard deviation is such that, for a given sample size, the standard error of the mean equals the standard deviation divided by the square root of the sample size.

      SEM = SD / square root (n)

      where SD = standard deviation and n = sample size

    • This question is part of the following fields:

      • Statistical Methods
      6
      Seconds
  • Question 27 - A 68-year-old man with nausea and vomiting is admitted to the hospital. For...

    Correct

    • A 68-year-old man with nausea and vomiting is admitted to the hospital. For temporal arteritis, he takes 40 mg prednisolone orally in divided doses. His prescription chart will need to be adjusted to reflect his inability to take oral medications. What is the equivalent dose of intravenous hydrocortisone to 40 mg oral prednisolone?

      Your Answer: 160 mg

      Explanation:

      Prednisolone 5 mg is the same as 20 mg hydrocortisone.

      Prednisolone 40 mg is the same as 8 x 20 mg or 160 mg of prednisolone.

      Mineralocorticoid effects and variations in action duration are not taken into account in these comparisons.

      5 mg of prednisolone is the same as Dexamethasone 750 mcg, Hydrocortisone 20 mg, Methylprednisolone 4 mg, and Cortisone acetate 25 mg.

    • This question is part of the following fields:

      • Pharmacology
      12.9
      Seconds
  • Question 28 - What is the percentage of values that lie within 3 standard deviations of...

    Correct

    • What is the percentage of values that lie within 3 standard deviations of the mean?

      Your Answer: 99.70%

      Explanation:

      99.7% of the values within 3 standard deviations of the mean.

      For 99.7% confidence interval, you can find the range as follows:

      1. Multiply the standard error by 3.

      2. Subtract the answer from mean value to get the lower limit.

      3. Add the answer obtained in step 1 from the mean value to get the upper limit.

      For a confidence interval of 68%, multiply the standard error with 1 and repeat the process. For a 95% confidence interval, Standard Error is multiplied by 1.96 to get the interval.

    • This question is part of the following fields:

      • Statistical Methods
      8.1
      Seconds
  • Question 29 - After consuming 12 g of paracetamol, a 37-year-old man is admitted to the...

    Incorrect

    • After consuming 12 g of paracetamol, a 37-year-old man is admitted to the medical admissions unit. He has hepatocellular necrosis in both clinical and biochemical aspects. The most significant reason for paracetamol causing toxicity is?

      Your Answer: The conjugation of paracetamol is a rapidly saturable process

      Correct Answer: Glutathione is rapidly exhausted

      Explanation:

      Phase I and phase II metabolism are used by the liver to break down paracetamol.

      1st Phase:

      Prostaglandin synthetase and cytochrome P450 (CYP1A2, CYP2E2, CYP3A4 and CYP2D6) to N-acetyl-p-benzoquinoneimine (NAPQI) and N-acetylbenzo-semiquinoneimine. NAPQI is a toxic metabolite that binds to the sulfhydryl groups of cellular proteins in hepatocytes, making it toxic. This can result in centrilobular necrosis.

      Glutathione and glutathione transferases prevent NAPQI from binding to hepatocytes at low paracetamol doses by preferentially binding to these toxic metabolites. The cysteine and mercapturic acid conjugates are then excreted in the urine. Depletion of glutathione occurs at higher doses of paracetamol, resulting in high levels of NAPQI and the risk of hepatocellular damage. Hepatotoxicity would not be an issue if the body’s glutathione stores were sufficient.

      N-acetylcysteine is a precursor for glutathione synthesis and is the drug of choice for the treatment of paracetamol overdose.

      Phase II:

      Conjugation with glucuronic acid to paracetamol glucuronide is the most common method of metabolism and excretion, accounting for 60% of renally excreted metabolites. Paracetamol sulphate (35%), unchanged paracetamol (5%), and mercapturic acid are among the other renally excreted metabolites (3 percent ). The capacity of conjugation pathways is limited. The capacity of the sulphate conjugation pathway is lower than that of the glucuronidation pathway.

      Because of the low pH in the stomach, paracetamol absorption is minimal (pKa value is 9.5). Paracetamol is absorbed quickly and completely in the alkaline environment of the small intestine. Oral bioavailability is extremely high, approaching 100%.

      As a result, measuring paracetamol levels in plasma after an injury is important. Peak plasma concentrations are reached after 30-60 minutes, with a volume of distribution of 0.95 L/kg. It binds to plasma proteins at a rate of 10% to 25%.

    • This question is part of the following fields:

      • Pharmacology
      16.9
      Seconds
  • Question 30 - During positive pressure ventilation using positive end-expiratory pressure (PEEP), there is usually an...

    Correct

    • During positive pressure ventilation using positive end-expiratory pressure (PEEP), there is usually an associated reduction in cardiac output Which of the following is responsible?

      Your Answer: Reduced venous return to the heart

      Explanation:

      The option that is most responsible is the progressive decrease in venous return of blood to the right atrium. The heart rate does not usually change with PEEP so the fall in cardiac output is due to a reduction in left ventricular (LV) stroke volume (SV).

      Note that the interventricular septum does shift toward the left and there is an increased pulmonary vascular resistance (PVR) from overdistention of alveolar air sacs that contribute to the reduction in cardiac output. Any increase in PVR will be associated with reduced pulmonary vascular capacitance.

    • This question is part of the following fields:

      • Pathophysiology
      15.2
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Anaesthesia Related Apparatus (1/1) 100%
Pathophysiology (5/6) 83%
Physiology And Biochemistry (2/2) 100%
Clinical Measurement (0/1) 0%
Pharmacology (4/7) 57%
Anatomy (6/7) 86%
Physiology (1/2) 50%
Statistical Methods (2/4) 50%
Passmed