00
Correct
00
Incorrect
00 : 00 : 0 00
Session Time
00 : 00
Average Question Time ( Secs)
  • Question 1 - An acidic drug with a pKA of 4.3 is injected intravenously into a...

    Incorrect

    • An acidic drug with a pKA of 4.3 is injected intravenously into a patient. At a normal physiological pH, the approximate ratio of ionised to unionised forms of this drug in the plasma is?

      Your Answer: 10:01

      Correct Answer: 1000:01:00

      Explanation:

      The pH at which the drug exists in 50 percent ionised and 50 percent unionised forms is known as the pKa.

      To calculate the proportion of ionised to unionised form of an ACID, use the Henderson-Hasselbalch equation.

      pH = pKa + log ([A-]/[HA])

      or

      pH = pKa + log [(salt)/(acid)]
      pH = pKa + log ([ionised]/[unionised]).

      Hence, if the pKa ˆ’ pH = 0, then 50% of drug is ionised and 50% is unionised.

      In this example:

      7.4 = 4.3 + log ([ionised]/[unionised])
      7.4 ˆ’ 4.3 = log ([ionised]/[unionised])
      log 3.1 = log ([ionised]/[unionised])

      Simply put, the antilog is the inverse log calculation. In other words, if you know the logarithm of a number, you can use the antilog to find the value of the number. The antilogarithm’s definition is as follows:

      y = antilog x = 10x

      Antilog to the base 10 of 0 = 1, 1 = 10, 2 =100, 3 = 1000, and 4 = 10,000.

      If you want to find the antilogarithm of 3.1, for a number between 3 and 4, the antilogarithm will return a value between 1000 and 10,000. The ratio is 1:1 if pKa = pH, that is, pH pKa = log 0. (50 percent ionised and unionised).

      According to the above value, there is only one unionised molecule for every approximately 1000 (1259) ionised molecules of this drug in plasma, implying that this drug is largely ionised in plasma (99.99 percent ).

    • This question is part of the following fields:

      • Pharmacology
      205.1
      Seconds
  • Question 2 - The Medical Admissions unit receives a 71-year-old woman. She has type 2 diabetes,...

    Incorrect

    • The Medical Admissions unit receives a 71-year-old woman. She has type 2 diabetes, which she manages with diet, but she has been feeling ill for the past 48 hours. Her pulse rate is 110 beats per minute, her blood pressure is 90/50 mmHg, and she is clinically dehydrated. Her respiratory rate is 20 breaths per minute, and chest auscultation reveals no focal signs. The following are the lab results: Glucose 27.4 mmol/L (3.5-5.5), Ketones 2.5 mmol/L (<0.1), Urinary glucose is zero (dipstick) with ketones. A random blood glucose of 15.3 mmol/L was measured during a visit to the diabetic clinic one month prior to admission, according to her notes, and a urinary dipstick registered a high glucose and ketones++. The discrepancy between plasma and urinary glucose measurements is best explained by which of the following physiological mechanisms?

      Your Answer: The glucose transport maximum (Tm) is abnormally high

      Correct Answer: The glomerular filtration rate is abnormally low

      Explanation:

      The glucose molecule enters the Bowman’s capsule freely and becomes part of the filtrate.

      All glucose is reabsorbed in the proximal convoluted tubule when blood glucose concentrations are below a certain threshold (approximately 11 mmol/L) (PCT). Active transportation makes this possible. In the proximal tubular cells, sodium/glucose cotransporters (SGLT1 and SGLT2) are the proteins responsible.

      Glucose does not normally appear in the urine below the renal threshold.

      The renal glucose threshold is not set in stone and is affected by a variety of factors, including GFR, TmG, and the quantity of splay.

      The different absorptive and filtering capacities of individual nephrons cause splay, which is the rounding of a glucose reabsorption curve.

      The SGLT proteins have a high affinity for glucose, but not an infinite affinity. As a result, some glucose may escape reabsorption before the TmG. A decrease in renal threshold may be caused by an increase in splay.

      Because the filtered glucose load is reduced and the PCT can reabsorb all of the filtered glucose despite hyperglycaemia, a low GFR causes an increase in TmG. In contrast, lowering the TmG lowers the threshold because the tubules’ ability to reabsorb glucose is reduced.

      A reduction in GFR caused by severe dehydration and reduced perfusion pressure is the most obvious cause of the discrepancy between plasma and urinary glucose in this scenario.

    • This question is part of the following fields:

      • Pathophysiology
      81.2
      Seconds
  • Question 3 - Very small SI units are easily expressed using mathematical prefixes. One femtolitre is...

    Incorrect

    • Very small SI units are easily expressed using mathematical prefixes. One femtolitre is equal to which of the following volumes?

      Your Answer: 0.000, 000, 000, 001 L

      Correct Answer: 0.000, 000, 000, 000, 001 L

      Explanation:

      Small measurement units are denoted by the following SI mathematical prefixes:

      1 deci = 0.1
      1 milli = 0.001
      1 micro = 0.000001
      1 nano = 0.000000001
      1 pico = 0.000000000001
      1 femto = 0.000000000000001 (used to measure red blood cell volume)
      1 atto = 0.000000000000000001.

    • This question is part of the following fields:

      • Basic Physics
      53.9
      Seconds
  • Question 4 - Which of the following options will best reflect the adequacy of preoxygenation prior...

    Correct

    • Which of the following options will best reflect the adequacy of preoxygenation prior to rapid sequence induction of a patient?

      Your Answer: Expired fraction of oxygen (FEO2)

      Explanation:

      The most important determinant of preoxygenation adequacy is expired fraction of oxygen. Denitrogenating of the functional residual capacity is the purpose of preoxygenation. This is dependent on three vital factors: (1) respiratory rate; (2) inspired volume, and; (3) inspired oxygen concentration (FiO2).

      Arterial oxygen saturation does not efficiently determine adequacy of preoxygenation because of its inability to measure tissue reserves. Arterial partial pressure of oxygen is also unsuitable for determining preoxygenation adequacy. Moreover, the absence of central cyanosis is a very crude sign of low tissue oxygenation.

    • This question is part of the following fields:

      • Pathophysiology
      12.5
      Seconds
  • Question 5 - Which of the following correctly explains the mechanism of lowering blood pressure by...

    Incorrect

    • Which of the following correctly explains the mechanism of lowering blood pressure by nitroglycerine?

      Your Answer: Nitric oxide

      Correct Answer: Acetylcholine

      Explanation:

      Nitroglycerine is rapidly denitrated enzymatically in the smooth muscle cell to release the free radical nitric oxide (NO).
      Released NO activated cytosolic guanylyl cyclase which increases cGMP (cyclin guanosine monophosphate) which causes dephosphorylation of myosin light chain kinase (MLCK) through a cGMP-dependent protein kinase.
      Reduced availability of phosphorylated (active) MLCK interferes with activation of myosin and in turn, it fails to interact with actin to cause contraction. Consequently, relaxation occurs.

    • This question is part of the following fields:

      • Pharmacology
      9.6
      Seconds
  • Question 6 - A 74-year-old man presents to a hospital for manipulation of Colles fracture. The...

    Correct

    • A 74-year-old man presents to a hospital for manipulation of Colles fracture. The patient is 50 kg and the anaesthetic plan is to perform an intravenous regional (Bier's) block. Which of the following is the appropriate dose of local anaesthetic for the procedure?

      Your Answer: 0.5% prilocaine (40 ml)

      Explanation:

      Prilocaine is the drug of choice for intravenous regional anaesthesia. 0.5% prilocaine (40 ml) is indicated for this condition.
      Lidocaine is another alternative for this condition but volume and dose are likely to be inadequate for the procedure.

    • This question is part of the following fields:

      • Pharmacology
      7
      Seconds
  • Question 7 - A radical neck dissection is being performed. The ENT surgeon wishes to expose...

    Correct

    • A radical neck dissection is being performed. The ENT surgeon wishes to expose the external carotid artery fully. He inserts a self-retaining retractor close to the origin of the external carotid artery. What structure lies posterolaterally to the external carotid at this point?

      Your Answer: Internal carotid artery

      Explanation:

      External carotid artery originates at the upper border of the thyroid cartilage. It ascends and lies anterior to the internal carotid arteries and posterior to the posterior belly of the digastric muscle and stylohyoid muscle.

      The external carotid artery has eight important branches:
      Anterior surface:
      1. Superior thyroid artery (first branch)
      2. Lingual artery
      3. Facial artery
      Medial branch
      4. Ascending pharyngeal artery
      Posterior branches
      5. Occipital artery
      6. Posterior auricular artery
      Terminal branches
      7. Maxillary artery
      8. Superficial temporal artery.

    • This question is part of the following fields:

      • Anatomy
      12.5
      Seconds
  • Question 8 - All of the following statements are true regarding calcium except: ...

    Incorrect

    • All of the following statements are true regarding calcium except:

      Your Answer: Hypocalcaemia may cause cardiac failure

      Correct Answer: Serum calcium accounts for 10% of total body calcium stores

      Explanation:

      Calcium is a very important ion and is involved in:
      -cell homeostasis
      -coagulation
      -muscle contraction
      -neuronal impulse transmission/membrane stabilization
      -bone formation and skeletal strength
      -secretion processes

      99% is found in bone and 1% in the plasma. Of the 1% that is in the plasma
      -45% is free ionized calcium
      -45% is bound to proteins, mainly Albumin
      -10% is present as an anion complex

      Reduced levels of IONIZED calcium give rise to features of hypocalcaemia , resulting in increased excitability of membranes. This results when the total calcium concentration goes below 2 mmol/L.

      Features of mild to moderate hypocalcaemia are:
      -paraesthesia (peri-oral, fingers)
      -tetany
      -spasm
      -muscle cramps
      -ECG changes (prolonged QT)
      -Trousseau’s sign (inflation of tourniquet induces carpopedal spasm)
      -Chvostek’s sign (tapping the facial nerve – cranial nerve VII – causes facial muscle twitch/spasm)

      Features of severe hypocalcaemia are:
      -cardiogenic shock and congestive cardiac failure due to reduced myocardial contractility
      respiratory distress due to bronchospasm, agitation, confusion, seizures

      Features of hypercalcaemia (remember ‘bones, stones, groans and psychic moans’):
      -Abdominal pain
      -Vomiting
      -Constipation
      -Polyuria
      -Polydipsia
      -Depression
      -Lethargy
      -Anorexia
      -Weight loss
      -Hypertension
      -Confusion
      -Pyrexia
      -Calcification in the cornea
      -Renal stones
      -Renal failure
      -Decreased Q-T interval
      -Cardiac shock/collapse

    • This question is part of the following fields:

      • Physiology And Biochemistry
      23
      Seconds
  • Question 9 - A log-dose response curve is plotted after drug A is given. The shape...

    Correct

    • A log-dose response curve is plotted after drug A is given. The shape of this curve is sigmoid, with a maximum response of 100%. The log-dose response curve of drug A shifts to the right with a maximum response of 100 percent when drug B is administered. What does this mean in terms of drug B?

      Your Answer: Drug B has affinity for the receptor but has no intrinsic efficacy

      Explanation:

      Drug A is a pure agonist for the receptor, with high intrinsic efficacy and affinity, according to the log-dose response curve.

      Drug B, on the other hand, works as a competitive antagonist. It binds to the receptor but has no inherent efficacy. Drug A’s efficacy will not change, but its potency will be reduced.

      A partial agonist is a drug with partial intrinsic efficacy and affinity for the receptor. Giving a partial agonist after a pure agonist will not increase receptor occupancy or decrease receptor activity, and thus will not affect drug A’s efficacy. The inverse agonist flumazenil can reverse all benzodiazepines.

      An inverse agonist is a drug that binds to the receptor but has the opposite pharmacological effect.

      A non-competitive antagonist is a drug that has affinity for a receptor but has different pharmacological effects and reduces the efficacy of an agonist for that receptor.

    • This question is part of the following fields:

      • Pharmacology
      54.1
      Seconds
  • Question 10 - During a stabbing incident, a 30-year-old injured his inferior vena cava. What number...

    Incorrect

    • During a stabbing incident, a 30-year-old injured his inferior vena cava. What number of functional valves can be usually found in this vessel?

      Your Answer: 2

      Correct Answer: 0

      Explanation:

      The inferior vena cava is formed by the union of the right and left common iliac veins. The inferior vena cava has no functional valves like the one-way valves commonly found in many veins. The forward flow to the heart is driven by the differential pressure created by normal respiration.

      The absence of functional valves has an important clinical role when cannulating during cardiopulmonary bypass.

      There is a valve that is non-functioning called the eustachian valve that lies at the junction of the IVC and the right atrium. This valve has a role to help direct the flow of oxygen-rich blood through the right atrium to the left atrium via the foramen ovale during fetal life. It has no specific function in adult life.

    • This question is part of the following fields:

      • Anatomy
      10.2
      Seconds
  • Question 11 - An arterial pressure transducer is supposedly in direct correlation to change, thus it...

    Incorrect

    • An arterial pressure transducer is supposedly in direct correlation to change, thus it is dependent on zero gradient drift and zero offset. Which of the following values will best compensate for the gradient drift?

      Your Answer: 200 mmHg and 760 mmHg

      Correct Answer: 0 mmHg and 200 mmHg

      Explanation:

      Since an arterial pressure transducer, and every other measuring apparatus, is prone to errors due to offset and gradient drifts, regular calibration is required to maintain accuracy of the instrument. The two-point calibration pressure values of 0 mmHg and 200 mmHg are within the physiologic range and can best compensate for the gradient drift.

    • This question is part of the following fields:

      • Clinical Measurement
      75.6
      Seconds
  • Question 12 - Regarding the Valsalva manoeuvre, which of the following describes the cardiovascular changes in...

    Incorrect

    • Regarding the Valsalva manoeuvre, which of the following describes the cardiovascular changes in phase III in a normal patient?

      Your Answer: Increased intrathoracic pressure, decrease in blood pressure, and increase in heart rate

      Correct Answer: Normal intrathoracic pressure, decrease in blood pressure, and increase in heart rate

      Explanation:

      When a person forcefully expires against a closed glottis, changes occur in intrathoracic pressure that dramatically affect venous return, cardiac output, arterial pressure, and heart rate. This forced expiratory effort is called a Valsalva maneuver.

      Initially during a Valsalva, intrathoracic (intrapleural) pressure becomes very positive due to compression of the thoracic organs by the contracting rib cage. This increased external pressure on the heart and thoracic blood vessels compresses the vessels and cardiac chambers by decreasing the transmural pressure across their walls. Venous compression, and the accompanying large increase in right atrial pressure, impedes venous return into the thorax. This reduced venous return, and along with compression of the cardiac chambers, reduces cardiac filling and preload despite a large increase in intrachamber pressures. Reduced filling and preload leads to a fall in cardiac output by the Frank-Starling mechanism. At the same time, compression of the thoracic aorta transiently increases aortic pressure (phase I); however, aortic pressure begins to fall (phase II) after a few seconds because cardiac output falls. Changes in heart rate are reciprocal to the changes in aortic pressure due to the operation of the baroreceptor reflex. During phase I, heart rate decreases because aortic pressure is elevated; during phase II, heart rate increases as the aortic pressure falls.

      When the person starts to breathe normally again, the intrathoracic pressure declines to normal levels, the aortic pressure briefly decreases as the external compression on the aorta is removed, and heart rate briefly increases reflexively (phase III). This is followed by an increase in aortic pressure (and reflex decrease in heart rate) as the cardiac output suddenly increases in response to a rapid increase in cardiac filling (phase IV). Aortic pressure also rises above normal because of a baroreceptor, sympathetic-mediated increase in systemic vascular resistance that occurred during the Valsava.

    • This question is part of the following fields:

      • Pathophysiology
      25
      Seconds
  • Question 13 - Which of the following statements is correct regarding hypomagnesaemia? ...

    Incorrect

    • Which of the following statements is correct regarding hypomagnesaemia?

      Your Answer: Causes hypercalcaemia

      Correct Answer: Causes tetany

      Explanation:

      The ECG changes seen in hypomagnesaemia include:

      Prolonged PR interval
      Prolonged QT interval
      Flattening of T waves
      ST segment depression
      Prominent U waves

      These changes are almost the same as those of hypokalaemia.

      There is an increased risk of digoxin toxicity and a risk of atrial and ventricular ectopic and ventricular arrhythmias.

      There is impaired synthesis and release of parathyroid hormone (PTH) in chronic hypomagnesaemia leading to impaired target organ response to PTH. This produces secondary hypocalcaemia.

      The use of potassium ‘wasting’ diuretics (e.g. loop diuretics like furosemide) may lead to Hypomagnesaemia.

      A tall T wave is seen in hypermagnesemia.

    • This question is part of the following fields:

      • Pathophysiology
      15.9
      Seconds
  • Question 14 - Which of the following statement is true regarding hypoxic pulmonary vasoconstriction (HPV)? ...

    Incorrect

    • Which of the following statement is true regarding hypoxic pulmonary vasoconstriction (HPV)?

      Your Answer: The vasoconstriction occurs when the PaO2 is below 50mmHg (6.5 kPa)

      Correct Answer: 20 parts per million (ppm) of nitric oxide will reduce hypoxic pulmonary vasoconstriction

      Explanation:

      Hypoxic Pulmonary vasoconstriction (HPV) reflects the constriction of small pulmonary arteries in response to hypoxic alveoli (.i.e.; PO2 below 80-100mmHg or 11-13kPa).

      These blood vessels become independent of the nerve stimulus, when blood with a high PO2 flows through the lung which contains a low alveolar PO2.

      Thus a low PO2 within the alveoli has been shown to impact on hypoxic pulmonary vasoconstriction (HPV) more than a low PO2 within the blood.

      HPV results in the blood flow being directed away from poorly ventilated areas of the lung and helps to reduce the ventilation/perfusion mismatch (not increase).

      In animals, volatile anaesthetic agents can diminish HPV, while in adults, the evidence proves less persuading, in spite of the fact that it certainly doesn’t strengthen the effects.

      HPV response will be suppressed by 20 parts per million (ppm) of nitric oxide.

    • This question is part of the following fields:

      • Physiology
      77.2
      Seconds
  • Question 15 - Which of the following options will cause an artificial increase in pulse oximeter...

    Incorrect

    • Which of the following options will cause an artificial increase in pulse oximeter (SpO2) readings?

      Your Answer: Brown-red nail polish on finger

      Correct Answer: Heavy smoker

      Explanation:

      A pulse oximeter is a piece of medical equipment used as a non-invasive method of measuring the oxygen saturation of blood.

      It works by measuring the ratio of absorption of red and infrared light in a section of blood flow, as red light is largely absorbed by deoxygenated blood, and infrared light is largely absorbed by oxygenated blood.

      Pulse oximetry relies on photoplethysmography (PPG) waveforms. The oximeter has 2 sides, with different functions. One side houses light-emitting diodes which are responsible for transmitting 2 light wavelengths, 660nm for red light and 940nm for near infrared light. The other side is a photodetector. The light emitted travels through the body and the amount that is not absorbed is measured by the photodetector.

      Smokers often have increased levels of carboxy haemoglobin (COHb). This leads to artificial increases in pulse oximeter readings as it is unable to differentiate between COHb and oxyhaemoglobin (O2HB) as they both absorb red light at 660nm. Every 1% increase of circulating carboxyhaemoglobin, results in a correlative 1% increase in oximeter readings.

      Prilocaine toxicity will cause an artificial decrease in oximeter readings. This is because prilocaine metabolites cause methemoglobinemia (MetHB), which are dysfunctional haemoglobins unable to properly transport oxygen. In this case, a laboratory multiwavelength co-oximeter is recommended for a more accurate reading.

      Anaemia will not affect oximeter readings as long as haemoglobins in the blood are normal.

      Sickle cell disease does not affect oximeter readings despite its ability to cause hypoxia and shift the oxygen dissociation curve to the right.

      Brown-red fingernail polish will cause an underestimation of pulse oximeter readings.

    • This question is part of the following fields:

      • Clinical Measurement
      34.3
      Seconds
  • Question 16 - An 18-year old female was brought into the emergency room because of active...

    Correct

    • An 18-year old female was brought into the emergency room because of active seizures. The informant reported that it has been more than 5 minutes since the patient started seizing. The attending physician gave an initial diagnosis of status epilepticus. According to the paramedics who brought in the patient, 10 mg of diazepam was given rectally. Upon physical examination, she was normotensive at 120/80 mmHg; tachycardic at 138 beats per minute; tachypnoeic at 24 breaths per minute; and well-saturated at 99% on high flow oxygen. Her random blood glucose level was normal at 7.0 mmol/L. Given this situation and an initial diagnosis of status epilepticus, what would be the best initial anti-epileptic drug to administer to the patient?

      Your Answer: Lorazepam

      Explanation:

      Lorazepam is an intermediate-acting benzodiazepine that binds to the GABA-A receptor subunit to increase the frequency of chloride channel opening and facilitate membrane hyperpolarization. It is the preferred treatment for status epilepticus, although Diazepam can also be used as an alternative.

      Lorazepam has a longer duration of action than Diazepam, and binds with greater affinity to the GABA-A receptor subunit.

      Phenobarbital is a barbiturate that acts on the GABA-A receptor site to increase the duration of chloride channel opening. Barbiturates, particularly phenobarbital, is considered the drug of choice for seizures in infants.

      Phenytoin is a sodium-channel blocker that is given for generalized tonic-clonic seizures, partial seizures, and status epilepticus. Phenytoin is preferred in prolonged therapy for status epilepticus because it is less sedating.

      Propofol or thiopentone is preferred when airway protection is required.

    • This question is part of the following fields:

      • Pharmacology
      32.6
      Seconds
  • Question 17 - With regards to arterial oxygen content, which of the following contributes most from...

    Correct

    • With regards to arterial oxygen content, which of the following contributes most from a quantitative perspective?

      Your Answer: Haemoglobin concentration

      Explanation:

      The amount of oxygen carried by 100 ml of blood is called the arterial oxygen content (CaO2)and is normally 17-24 ml/dL and can be determined by this equation:

      CaO2 = oxygen bound to haemoglobin + oxygen dissolved in plasma

      CaO2 = (1.34 × Hgb × SaO2 × 0.01) + (0.003 × PaO2)

      where:

      1.34 = Huffner’s constant (D) – Huffner’s constant does not change and its magnitude relatively small.
      Hgb is the haemoglobin level in g/dL and SaO2 is the percent oxyhaemoglobin saturation of arterial blood
      PaO2 is (0.0225 = ml of O2 dissolved per 100 ml plasma per kPa, or 0.003 ml per mmHg).

      Quantitatively, the amount of oxygen dissolved in plasma is 0.3 mL/dL.

      Henry’s law states that at constant temperature, the amount of gas dissolved at equilibrium in a given quantity of a liquid is proportional to the pressure of the gas in contact with the liquid.

      Given a haemoglobin concentration of 15 g/dL and a SaO2 of 100% and a PaO2 of 13.3 kPa, the amount of oxygen bound to haemoglobin is 20.4 mL/100mL.

      Cardiac output is an important determinant of oxygen delivery but does not influence the oxygen content of blood.

    • This question is part of the following fields:

      • Basic Physics
      15.1
      Seconds
  • Question 18 - A 73-year-old woman is admitted to the coronary care unit. She has been...

    Correct

    • A 73-year-old woman is admitted to the coronary care unit. She has been diagnosed with an acute myocardial infarction and has gone into a cardiogenic shock. As part of her treatment, she is prescribed a dobutamine infusion and placed on full haemodynamic monitoring. Over the next four days, her measurement are: Day1 Day2 Day3 Day4 Infusion rate of dobutamine (mcg/kg/min): 5, 10, 15, 25. Cardiac output (L/min): 3.4, 3.2, 3.1, 3.2. Pulse rate (beats/min): 110, 112, 105, 100. Blood pressure (mmHg): 80/60, 75/61, 83/60, 81/56. Haemodynamic changes are noted as a result of response to treatment. What is the most probable cause?

      Your Answer: Tolerance by down-regulation of beta1 receptors

      Explanation:

      Tachyphylaxis is the swiftly declining response to successive drug doses which vastly reduces its effectiveness in a short space of time, mostly as a result of an acute consumption of neurotransmitters.

      Tolerance or desensitisation is the slow decline in a person’s reaction to a drug due to continued use. It requires a longer time span than tachyphylaxis, usually over days or weeks.

      Down- regulation is a reduction in the amount of receptors available on target cells which decreases the affinity of the agent to the cells. For this to occur, the down-regulation of receptors must occur at a rate faster than receptor synthesis. This down-regulation often occurs with beta1 receptors due to:

      1) The transportation or receptors from the cell surface to the interior of the cell

      2) Degradation of receptors occurring over time.

      In this case, dobutamine is prescribed to treat cardiogenic shock. It is able to function by binding to beta1-adrenergic receptors to increase the contraction of the heart, thereby improving cardiac output. It also binds to beta2- and alpha1-adrenergic receptors to balance out the effects produced by binding to beta1 receptors and reduce the risk of system vasculature responses.

    • This question is part of the following fields:

      • Clinical Measurement
      43.2
      Seconds
  • Question 19 - What is the primary purpose of funnel plots? ...

    Correct

    • What is the primary purpose of funnel plots?

      Your Answer: Demonstrate the existence of publication bias in meta-analyses

      Explanation:

      Funnel plot is essentially a scatterplot of the effect of treatment against a particular measure of study precision. Its primal purpose is to serve as a visual aid and help in detection of bias or systematic heterogenity.

    • This question is part of the following fields:

      • Statistical Methods
      17.5
      Seconds
  • Question 20 - What can you see within the tunica media of a blood vessel on...

    Correct

    • What can you see within the tunica media of a blood vessel on examination?

      Your Answer: Smooth muscle

      Explanation:

      The blood vessel well is divided into 3 parts, namely:

      The tunica intima, which is the deepest layer. It contains endothelial cells separated by gap junctions

      The tunica media, primarily consisting of the involuntary smooth muscle fibres, laid out in spiral layers with elastic fibres and connective tissue.

      The tunica adventitia, which is the most superficial layer. It consists of the vasa vasorum, fibroblast and collagen.

    • This question is part of the following fields:

      • Anatomy
      17.1
      Seconds
  • Question 21 - Levels of serum potassium in around 1000 patients that were on ACE inhibitor...

    Correct

    • Levels of serum potassium in around 1000 patients that were on ACE inhibitor were measured. The mean value was calculated to be 4.6mmol/L and a standard deviation of 0.3mmol/L was recorded. Which among the given options is correct?

      Your Answer: 68.3% of values lie between 4.3 and 4.9 mmol/l

      Explanation:

      Its known that 68.3% of the total values of a normally distributed variable are found within a range of 1 standard deviation from the mean which makes the range to be 4.3 to 4.9 mmol/L.

    • This question is part of the following fields:

      • Statistical Methods
      37.1
      Seconds
  • Question 22 - The following statements concern the sensory innervation of the nasal passage: ...

    Incorrect

    • The following statements concern the sensory innervation of the nasal passage:

      Your Answer: posteriorly the floor of the nose is supplied by the superior dental nerves

      Correct Answer: the infraorbital branch of the maxillary nerve supplies the vestibule

      Explanation:

      The walls of the anterior nasal passage are supplied by the anterior ethmoidal branch of the nasociliary nerve, and the floor is innervated by the superior dental nerve (not the sphenopalatine nerves).

      The walls and floor of the posterior nasal passage are innervated by the long and short sphenopalatine nerves and the great palatine nerve (not the superior dental nerves and the nasociliary nerve).

      The vestibule is innervated by small branches of the infraorbital branch of the maxillary nerve.

      The nasopharynx is innervated by the sensory branches of the trigeminal nerve (not the great palatine nerve).

    • This question is part of the following fields:

      • Anatomy
      45
      Seconds
  • Question 23 - A participant of a metabolism study is to be fed only granulated sugar...

    Correct

    • A participant of a metabolism study is to be fed only granulated sugar and water for 48 hours. What would be his expected respiratory quotient at the end of the study?

      Your Answer: 1

      Explanation:

      The respiratory quotient is the ratio of CO2 produced to O2 consumed while food is being metabolized:

      RQ = CO2 eliminated/O2 consumed

      Most energy sources are food containing carbon, hydrogen and oxygen. Examples include fat, carbohydrates, protein, and ethanol. The normal range of respiratory coefficients for organisms in metabolic balance usually ranges from 1.0-0.7.

      Granulated sugar is a refined carbohydrate with no significant fat, protein or ethanol content.

      The RQ for carbohydrates is = 1.0

      The RQ for the rest of the compounds are:

      Fats RQ = 0.7
      The chemical composition of fats differs from that of carbohydrates in that fats contain considerably fewer oxygen atoms in proportion to atoms of carbon and hydrogen.

      Protein RQ = 0.8
      Due to the complexity of various ways in which different amino acids can be metabolized, no single RQ can be assigned to the oxidation of protein in the diet; however, 0.8 is a frequently utilized estimate.

    • This question is part of the following fields:

      • Physiology
      6.5
      Seconds
  • Question 24 - In a normal healthy adult breathing 100 percent oxygen, which of the following...

    Incorrect

    • In a normal healthy adult breathing 100 percent oxygen, which of the following is the most likely cause of an alveolar-arterial (A-a) oxygen difference of 30 kPa?

      Your Answer: High altitude

      Correct Answer: Atelectasis

      Explanation:

      The ‘ideal’ alveolar PO2 minus arterial PO2 is the alveolar-arterial (A-a) oxygen difference.

      The ‘ideal’ alveolar PO2 is derived from the alveolar air equation and is the PO2 that the lung would have if there was no ventilation-perfusion (V/Q) inequality and it was exchanging gas at the same respiratory exchange ratio as real lung.

      The amount of oxygen in the blood is measured directly in the arteries.

      The A-a oxygen difference (or gradient) is a useful measure of shunt and V/Q mismatch, and it is less than 2 kPa in normal adults breathing air (15 mmHg). Because the shunt component is not corrected, the A-a difference increases when breathing 100 percent oxygen, and it can be up to 15 kPa (115 mmHg).

      An abnormally low or abnormally high V/Q ratio within the lung can cause an increased A-a difference, though the former is more common. Atelectasis, which results in a low V/Q ratio, is the most likely cause of an A-a difference in a healthy adult breathing 100 percent oxygen.

      Hypoventilation may cause an increase in alveolar (and thus arterial) CO2, lowering alveolar PO2 according to the alveolar air equation.

      The alveolar PO2 is also reduced at high altitude.

      Healthy people are unlikely to have a right-to-left shunt or an oxygen transport diffusion defect.

    • This question is part of the following fields:

      • Physiology
      52.5
      Seconds
  • Question 25 - During a squint surgery, a 5-year-old child developed severe bradycardia as a result...

    Incorrect

    • During a squint surgery, a 5-year-old child developed severe bradycardia as a result of the oculocardiac reflex. The afferent limb of this reflex is formed by which nerve?

      Your Answer: Optic nerve

      Correct Answer: Trigeminal nerve

      Explanation:

      When the eye is compressed or the extra-ocular muscles are tractioned, the oculocardiac reflex causes a decrease in heart rate.

      The ophthalmic division of the trigeminal nerve provides the afferent limb. This synapses with the vagus nerve’s visceral motor nucleus in the brainstem. The efferent signal is carried by the vagus nerve to the heart, where increased parasympathetic tone reduces sinoatrial node output and slows heart rate.

      The most common symptom is sinus bradycardia, but junctional rhythm and asystole can also occur.

    • This question is part of the following fields:

      • Pathophysiology
      12.2
      Seconds
  • Question 26 - Monitoring of which of the following is indicated in the prevention of propofol...

    Incorrect

    • Monitoring of which of the following is indicated in the prevention of propofol infusion syndrome?

      Your Answer: Lactate

      Correct Answer: Blood glucose

      Explanation:

      Propofol infusion syndrome (PRIS) is characterized by lactic acidosis, bradyarrhythmia, rhabdomyolysis, cardiac and renal failure, and often leads to death. So, lactate monitoring is advised inpatients with propofol infusion syndrome.

    • This question is part of the following fields:

      • Pharmacology
      38.1
      Seconds
  • Question 27 - You performed pelvic ultrasound of Mrs Aciman as she had pelvic bloating and...

    Correct

    • You performed pelvic ultrasound of Mrs Aciman as she had pelvic bloating and intermittent pain. The ultrasound shows a complex ovarian cyst and the radiologist who reported the results has advised urgent consultation with a gynaecologist. Upon breaking the news to Mrs Aciman you learn that she recently had a blood test done that was normal. You explain it to her that the test performed (Ca-125) is not always perfect and is only able to detect 80% of the cancer cases while the remaining 20% go undetected. Which statistical term appropriately explains the 80% in this example.

      Your Answer: Sensitivity

      Explanation:

      Tests are used to confirm the presence of a particular disease. However the results can be misleading at times since most of the tests have some limitations associated with them.
      Sensitivity is the correct term that refers to the probability of a positive test. The others are explained below:

      False Positive rates refer to the proportion of the patients who don’t have the condition being detected as positive.

      False Negative rates refer to the proportion of the patients who have the condition being detected as negative (like the 20% of the patients that went undetected by the Ca-125 test).

      Specificity describes the ability of a test to detect and pick up people without the disease. Absolute risk ratio compares the rate of two separate outcomes.

    • This question is part of the following fields:

      • Statistical Methods
      24.1
      Seconds
  • Question 28 - A new proton pump inhibitor (PPI) is being evaluated in elderly patients who...

    Correct

    • A new proton pump inhibitor (PPI) is being evaluated in elderly patients who are taking aspiring. Study designed has 120 patients receiving the PPI, while a control group of 240 individuals is given the standard PPI. Over a span of 6 years, 24 of the group receiving the new PPI had an upper GI bleed compared to 60 individuals who received the standard PPI. How would you calculate the absolute risk reduction?

      Your Answer: 5%

      Explanation:

      Absolute risk reduction = (Control event rate) – (Experimental event rate)

      Experimental event rate = 24 / 120 = 0.2

      Control event rate = 60 / 240 = 0.25

      Absolute risk reduction = 0.25 – 0.2 = 0.05 = 5% reduction

    • This question is part of the following fields:

      • Statistical Methods
      53.2
      Seconds
  • Question 29 - An elective left colectomy is being performed on a 60-year old male for...

    Correct

    • An elective left colectomy is being performed on a 60-year old male for left-sided colon cancer. The upper and lower parts of the descending colon are supplied by the left colic artery. Which of the following arteries gives rise to the left colic artery?

      Your Answer: Inferior mesenteric artery

      Explanation:

      The inferior mesenteric artery originates 3-4 cm above the bifurcation of the abdominal aorta. The left colic artery branches off the inferior mesenteric artery, arising close to its origin from the abdominal aorta. Other branches of IMA include the three sigmoid arteries that supply the sigmoid colon.

      The left colic artery branches off from IMA to supply the distal 1/3 of the transverse colon and the descending colon. It moves upwards posterior to the left colic mesentery and then travels anteriorly to the psoas major muscle, left ureter, and left internal spermatic vessels, before dividing into ascending and descending branches.

    • This question is part of the following fields:

      • Anatomy
      16.9
      Seconds
  • Question 30 - Which structure does NOT lie in the posterior triangle of the neck? ...

    Incorrect

    • Which structure does NOT lie in the posterior triangle of the neck?

      Your Answer: Phrenic nerve

      Correct Answer: Internal jugular vein

      Explanation:

      The sternocleidomastoid muscle divides the neck into anterior and posterior triangles on both sides of the neck.

      The posterior triangle has the following boundaries:
      anteriorly – sternocleidomastoid muscle
      posteriorly – trapezius
      roof – investing layer of deep cervical fascia
      floor – prevertebral fascia overlying splenius capitis, levator scapulae, and the scalene muscles

      The contents of the posterior triangle are:
      1. fat
      2. lymph nodes (level V)
      3. accessory nerve
      4. cutaneous branches of the cervical plexus (A major branch of this plexus is the phrenic nerve, which arises from the anterior divisions of spinal nerves C3-C5)
      5. inferior belly of omohyoid
      6. branches of the thyrocervical trunk (transverse cervical and suprascapular arteries)
      7. third part of the subclavian artery
      8. external jugular vein.

    • This question is part of the following fields:

      • Anatomy
      8.7
      Seconds
  • Question 31 - In asthmatic patients, non-steroidal anti-inflammatory analgesics (NSAIDs) are generally contraindicated. Which of the...

    Correct

    • In asthmatic patients, non-steroidal anti-inflammatory analgesics (NSAIDs) are generally contraindicated. Which of the following membrane phospholipid metabolism products is most likely to cause NSAID-induced bronchospasm in asthmatic patients who are predisposed to it?

      Your Answer: Leukotrienes

      Explanation:

      Nonsteroidal anti-inflammatory drugs (NSAIDs) cause bronchospasm, rhinorrhoea, and nasal obstruction in some asthma patients.

      The inhibition of cyclooxygenase-1 (Cox-1) appears to be the cause of NSAID-induced reactions. This activates the lipoxygenase pathway, which increases the release of cysteinyl leukotrienes (Cys-LTs), which causes bronchospasm and nasal obstruction.

      The following changes in arachidonic acid (AA) metabolism have been observed in NSAID-intolerant asthmatic patients:

      Prostaglandin E2 production is low, possibly due to a lack of Cox-2 regulation.
      An increase in leukotriene-C4 synthase expression and
      A decrease in the production of metabolites (lipoxins) released by AA’s transcellular metabolism.

      Phospholipase A produces membrane phospholipids, which are converted to arachidonic acid.

      TXA2 causes vasoconstriction as well as platelet aggregation and adhesion.

      PGI2 causes vasodilation and a reduction in platelet adhesion.

      PGE2 is involved in parturition initiation and maintenance, as well as thermoregulation.

    • This question is part of the following fields:

      • Pharmacology
      8.1
      Seconds
  • Question 32 - Which of the following statement is true regarding the paediatric airway? ...

    Correct

    • Which of the following statement is true regarding the paediatric airway?

      Your Answer: The larynx is more anterior than in an adult

      Explanation:

      In the neonatal stage, the tongue is usually large and comes to the normal size at the age of 1 year. The vocal cords lie inverse C4 and as it reaches the grown-up position inverse C5/6 by the age of 4 (not 1 year).

      Due to the immature cricoid cartilage, the larynx lies more anterior in newborn children. That’s why the cricoid ring is the narrowest part of the paediatric respiratory tract, while in the adults the tightest portion of the respiratory route is vocal cords. The epiglottis is generally expansive and slants at a point of 45 degrees to the laryngeal opening.

      The carina is the ridge of the cartilage in the trachea at the level of T2 in newborn (T4 in adults), that separates the openings of right and left main bronchi.

      Neonates have a comparatively low number of alveoli and then this number gradually increases to a most extreme by the age of 8 (not 3 years).

      Neonates are obligatory nose breathers and any hindrance can cause respiratory issues (e.g., choanal atresia).

    • This question is part of the following fields:

      • Physiology
      27
      Seconds
  • Question 33 - Which of the following bias is more prone to case-control studies? ...

    Correct

    • Which of the following bias is more prone to case-control studies?

      Your Answer: Recall bias

      Explanation:

      Omitted variable bias occurs when a statistician passes over one or more relevant variables from the study.

      Publication bias occurs in publish academic research. it occurs when the results of the study effect the decision whether to publish or not.

      Expectation bias occurs when the expectation of a researcher about the results effect the behaviour of the participants. Expectations may come from communication and experiences.

      Work up bias occurs in the study of diagnostic test validity, whether a gold standard procedure has been used. work up bias can seriously affect the specificity of the test.

      Recall bias introduced when participants in a study are systematically more or less likely to recall and relate information on exposure depending on their outcome status. Recall bias is more potential for Case-control studies.

    • This question is part of the following fields:

      • Statistical Methods
      13.8
      Seconds
  • Question 34 - Which statement best describes the bispectral index (BIS)? ...

    Correct

    • Which statement best describes the bispectral index (BIS)?

      Your Answer: It decreases during normal sleep

      Explanation:

      The bispectral index (BIS) is one of several systems used in anaesthesiology as of 2003 to measure the effects of specific anaesthetic drugs on the brain and to track changes in the patient’s level of sedation or hypnosis. It is a complex mathematical algorithm that allows a computer inside an anaesthesia monitor to analyse data from a patient’s electroencephalogram (EEG) during surgery. It is a dimensionless number (0-100) that is a summative measurement of time domain, frequency domain and high order spectral parameters derived from electroencephalogram (EEG) signals.

      Sleep and anaesthesia have similar behavioural characteristics but are physiologically different but BIS monitors can be used to measure sleep depth. With increasing sleep depth during slow-wave sleep, BIS levels decrease. This correlates with changes in regional cerebral blood flow when measured using positron emission tomography (PET).

      BIS shows a dose-response relationship with the intravenous and volatile anaesthetic agents. Opioids produce a clinical change in the depth of sedation or analgesia but fail to produce significant changes in the BIS. Ketamine increases CMRO2 and EEG activity.

      BIS is unable to predict movement in response to a surgical stimulus. Some of these are spinal reflexes and not perceived by the cerebral cortex.

      BIS is used during cardiopulmonary bypass to measure depth of anaesthesia and an index of cerebral perfusion. However, it cannot predict subtle or significant cerebral damage.

    • This question is part of the following fields:

      • Physiology
      12
      Seconds
  • Question 35 - A 58-year-old man, visits his general practitioner complaining of a lump in his...

    Incorrect

    • A 58-year-old man, visits his general practitioner complaining of a lump in his groin. He explains he is otherwise well and reports no other symptoms. The lump is examined and is found to be soft, and can be reduced without causing the patient pain. The GP diagnoses an inguinal hernia. To determine the nature of the hernia, the GP reduced the lump and applies pressure on the deep inguinal ring. The deep inguinal ring has what anatomical landmark?

      Your Answer: Superior to the mid inguinal point

      Correct Answer: Superior to the midpoint of the inguinal ligament

      Explanation:

      The deep inguinal ring lies approximately 1.5-2cm above the midpoint of the inguinal ligament, the halfway point between the anterior superior iliac spine and the pubic tubercle, next to the epigastric vessels.

      It is an important point in determining the nature of an inguinal hernia (direct or indirect). The patient is asked to cough after the hernia is reduced, with pressure applied to the deep inguinal ring. The hernia reappearing indicates it is direct, moving through the posterior wall of the inguinal canal.

      Inferior and lateral to the pubic tubercle is the normal anatomical position of the neck of a femoral hernia.

      Superior and medial to the pubic tubercle is the site of the superficial inguinal ring, and the normal anatomical position of the neck of an inguinal hernia.

      The mid-inguinal point is located halways between the pubic symphysis and the anterior superior iliac spine. It is the surface marking for taking the femoral pulse.

    • This question is part of the following fields:

      • Anatomy
      30.5
      Seconds
  • Question 36 - The equipment used for patient monitoring in theatre and intensive care settings have...

    Correct

    • The equipment used for patient monitoring in theatre and intensive care settings have electrical safety requirements for the protection of hospital staff and patients. Of the different classes of electrical equipment listed, which is least likely to cause a patient to suffer a microshock?

      Your Answer: II (CF)

      Explanation:

      Microshock refers to ventricular fibrillation caused by miniscule amounts of currents or voltages (100-150 microamperes) passing through the myocardial tissue from external cables arising from electrical components within the cardiac muscle, for example, pacemaker electrodes or saline filled venous catheters.
      The risk of shock changes with the construction of electrical equipment in question. The main classes of electrical equipment include: I: Appliances have a protective earth connected to an outer casing which prevents live elements from coming in contact with conductive elements. A fault in this equipment class will result in live elements coming in contact with the outer casing and allowing electrical flow into the protective earth. This triggers the protective fuse to disconnect the electric supply to the appliance.
      II: These appliances have reinforced insulation. In the event of a fault which causes the first layer of insulation to fail, the second layer is able to prevent contact of live elements with outer casing.
      III: These appliances have no insulation to provide safety, and rely solely on the use of separated extra low voltage source (SELV) which limits voltage to 25V AC or 60V DC allowing for a person to come in contact with it without risk of a shock under normal dry conditions. Under wet conditions, voltage supply should be lowered to reduce risk of shock. These devices have no risk of macroshocks, but some risk of microshocks.
      Class I and II electrical appliances are further divided into subtypes developed to limit current leakage in the event of a singular fault:
      B (body): Upper limit of current leakage is 500 µA. This current can cause skin tingling and microshocks, but is not sufficient to cause injury.
      BF (body floating): These appliances have an isolating capacitor or transformer which separate the secondary circuit from the protective earth. The upper limit of current leakage is the same as type B.
      CF (cardiac floating): Upper limit of leakage current during a singular fault is 50 microamps. It is least likely to result in a microshock.

    • This question is part of the following fields:

      • Anaesthesia Related Apparatus
      4.8
      Seconds
  • Question 37 - A 43-year-old patient was brought to the emergency department with a traumatic amputation...

    Incorrect

    • A 43-year-old patient was brought to the emergency department with a traumatic amputation of his leg at mid-thigh level. Resuscitation with 1 L gelofusine was done and four units of packed red blood cells were given before theatre. Thirty minutes following blood transfusion, the patient became flushed, breathless, hypotensive, develops haemoglobinuria, and had a fever of 38oC. Which one of the following correctly explains the patient signs and symptoms?

      Your Answer: Extravascular haemolytic transfusion reaction

      Correct Answer: Activation of classic complement pathway

      Explanation:

      This may be the classical case of blood transfusion reaction due to ABO incompatibility.

      Here red cells are destroyed in the bloodstream with the release of haemoglobin in circulation (causing haemoglobinuria). Here, IgM or IgG anti-A or anti-B antibody can cause rapid activation of complement cascade usually the classical pathway. This is called intravascular haemolysis.

      There may be extravascular haemolysis by cells of the mononuclear phagocyte system situated in the liver and spleen. Extravascular red cell destruction can increase breakdown products of haemoglobin, such as bilirubin and urobilinogen.

    • This question is part of the following fields:

      • Pathophysiology
      56.5
      Seconds
  • Question 38 - Blood pressure monitoring is a requirement for in-patient care. Different factors can result...

    Correct

    • Blood pressure monitoring is a requirement for in-patient care. Different factors can result in an inaccurate blood pressure reading, including the damping of an arterial waveform. How does a damped arterial waveform affect blood pressure measurements?

      Your Answer: The systolic pressure is lower and the diastolic pressure higher with the same mean

      Explanation:

      Damping is the reduction of energy in a system achieved by reducing the amplitude of oscillations. It is necessary to some degree to prevent wave overshoots.

      Critical damping usually causes the system to be slow, so optimal damping is normally applied to provide a balance between speed and distortion.

      Damping can cause errors if excessive (overdamping) or inadequate (Underdamping). The amount of damping in a system can be determined using the damping coefficient (D), where:

      Undamped: 0
      Critically damped: 1
      Optimally damped: 0.64

      An overdamped system will cause an artificial decrease in the systolic blood pressure, and an artificial increase in the diastolic blood pressure.

      An underdamped system will cause an artificial increase in systolic blood pressure and an artificial decrease in diastolic blood pressure.

      Damping can be caused by a number of factors affecting different parts of the system, including:

      The tubing/cannula: The presence of air bubbles, increased blood viscosity or formation of blood clots.
      The diaphragm/tubing: Increased malleability/compliance
      The tubing: Presence of kinks, narrowing or too many ports of injection.

      The answer here is a damped system will have a low systolic pressure, a high diastolic pressure with a normal mean pressure.

    • This question is part of the following fields:

      • Clinical Measurement
      16
      Seconds
  • Question 39 - In which of the following situations will a regional fall in cerebral blood...

    Correct

    • In which of the following situations will a regional fall in cerebral blood flow occur, suppose there is no changes in the mean arterial pressure (MAP)?

      Your Answer: Hyperoxia

      Explanation:

      The response of cerebral blood flow (CBF) to hyperoxia (PaO2 >15 kPa, 113 mmHg), the cerebral oxygen vasoreactivity is less well defined. A study originally described, using a nitrous oxide washout technique, a reduction in CBF of 13% and a moderate increase in cerebrovascular resistance in subjects inhaling 85-100% oxygen. Subsequent human studies, using a variety of differing methods, have also shown CBF reductions with hyperoxia, although the reported extent of this change is variable. Another study assessed how supra-atmospheric pressures influenced CBF, as estimated by changes in middle cerebral artery flow velocity (MCAFV) in healthy individuals. Atmospheric pressure alone had no effect on MCAFV if PaO2 was kept constant. Increases in PaO2 did lead to a significant reduction in MCAFV; however, there were no further reductions in MCAFV when oxygen was increased from 100% at 1 atmosphere of pressure to 100% oxygen at 2 atmospheres of pressure. This suggests that the ability of cerebral vasculature to constrict in response to increasing partial pressure of oxygen is limited.

      Increases in arterial blood CO2 tension (PaCO2) elicit marked cerebral vasodilation.

      CBF increases with general anaesthesia, ketamine anaesthesia, and hypoviscosity.

    • This question is part of the following fields:

      • Physiology
      44.5
      Seconds
  • Question 40 - Which of the following statements is true regarding the Wrights Respirometer? ...

    Correct

    • Which of the following statements is true regarding the Wrights Respirometer?

      Your Answer: Measures the minute volume to within an accuracy of +/- 10%

      Explanation:

      A Wrights Respirometer measures the volume of air exhaled over the course of one minute of normal breathing

      It is unidirectional and measures tidal volume and minute volume of gas flow in one direction. It is placed at the expiratory side (lower pressure than inspiratory side therefore lower chances of gas leaks)

      Slits are arranged such that incoming gas will rotate the vane at a rate of 150 revolutions per litre of flowing gas

      The Wright respirometer tends to over-read at high flow rates and under-read at low flows because of mechanical causes like friction and inertia and the accumulation of water vapour

      The ideal flow for accurate readings is 2 L/min for the respirometer. The respirometer reads the tidal volume and minute volume with a ±5€“10% accuracy within the range of 4€“24 L/min.

    • This question is part of the following fields:

      • Anaesthesia Related Apparatus
      31.9
      Seconds
  • Question 41 - Which of the following statement is true or false regarding to the respiratory...

    Correct

    • Which of the following statement is true or false regarding to the respiratory tract?

      Your Answer: The sympathetic innervation of the bronchi is derived from T2 - T4

      Explanation:

      The diaphragm has three opening through which different structures pass from the thoracic cavity to the abdominal cavity:

      Inferior vena cava passes at the level of T8.

      Oesophagus, oesophageal vessels and vagi at T10.

      Aorta, thoracic duct and azygous vein through T12.

      Sympathetic trunk and pulmonary branches of vagus nerve form a posterior pulmonary plexus at the root of the lung. Fibres continue posteriorly from superficial cardiac plexus to form Anterior pulmonary plexus. It contains vagi nerves and superficial cardiac plexus. These fibres then follow the blood vessel and bronchi into the lungs.

      The lower border of the pleura is at the level of:

      8th rib in the midclavicular line

      10th rib in the lower level of midaxillary line

      T12 at its termination.

      Both lungs have oblique fissure while right lung has transverse fissure too.

      The trachea expands from the lower edge of the cricoid cartilage (at the level of the 6th cervical vertebra) to the carina.

    • This question is part of the following fields:

      • Physiology
      8.3
      Seconds
  • Question 42 - About low molecular weight (LMW) heparin, Which of these is true? ...

    Correct

    • About low molecular weight (LMW) heparin, Which of these is true?

      Your Answer: Is excreted in the urine

      Explanation:

      Low molecular weight heparin (LMWH) creates a complex by binding to antithrombin. This complex binds with and inactivates factor Xa.

      There is less risk of bleeding with LMWH because it binds less to platelets, endothelium and von Willebrand factor.

      LMW binds Xa more readily. The shorter chains are less likely to bind both antithrombin and thrombin.

      There is need for monitoring in renal impairment because LMHW is excreted in the urine (and partly by hepatic metabolism)

      LMWH have been shown to be as efficacious as unfractionated heparin. It is also safer and have improved inpatient stay and reduced hospital cost.

    • This question is part of the following fields:

      • Pharmacology
      10.6
      Seconds
  • Question 43 - Which of the following statements is not correct regarding dopamine? ...

    Correct

    • Which of the following statements is not correct regarding dopamine?

      Your Answer: Crosses the blood brain barrier

      Explanation:

      Dopamine (DA) is a dopaminergic (D1 and D2) as well as adrenergic α and β1 (but not β2 ) agonist.

      The D1 receptors in renal and mesenteric blood vessels are the most sensitive: i.v. infusion of a low dose of DA dilates these vessels (by raising intracellular cAMP). This increases g.f.r. In addition, DA exerts a natriuretic effect by D1 receptors on proximal tubular cells.

      Moderately high doses produce a positive inotropic (direct β1 and D1 action + that due to NA release), but the little chronotropic effect on the heart.

      Vasoconstriction (α1 action) occurs only when large doses are infused.

      At doses normally employed, it raises cardiac output and systolic BP with little effect on diastolic BP. It has practically no effect on nonvascular α and β receptors; does not penetrate the blood-brain barrier€”no CNS effects.

      Dopamine is used in patients with cardiogenic or septic shock and severe CHF wherein it increases BP and urine outflow.

      It is administered by i.v. infusion (0.2€“1 mg/min) which is regulated by monitoring BP and rate of urine formation

    • This question is part of the following fields:

      • Pharmacology
      28.1
      Seconds
  • Question 44 - Regarding the carbon dioxide monitoring, which of the following statements is correct? ...

    Correct

    • Regarding the carbon dioxide monitoring, which of the following statements is correct?

      Your Answer: Carbon dioxide absorbs infrared radiation at 4.28 µm

      Explanation:

      Carbon dioxide (CO2), is a carbonic gas made up of two dissimilar atoms, namely one carbon atom and two oxygen atoms. Capnography is a technique used to measure carbon dioxide during a respiratory cycle, and it consists in calculating the concentration of the partial pressure of CO2, through the absorption of the infrared light, namely that CO2 absorbs infrared radiation at a wavelength of 4.28 µm.

      End-tidal CO2 (ETCO2), referring to the level of the carbon dioxide released at the end of an exhaled breath, is required to be continuously monitored, especially in ventilated patients, as it is a sensitive and a non invasive technique that provides immediate information about ventilation, circulation, and metabolism functions. ETCO2 is normally lower than the arterial partial pressure and varies between 0.6 and 0.7 kPa.

      There are two methods used to measure carbon dioxide. The sidestream capnometer method samples gases at a set flow rate (150-200 mL/min) from a sampling area through small diameter tubing, and the mainstream analyser method that uses a direct measurement of the patient exhaled CO2 by a relatively large and heavy sensors. Sidestram method allows the analysis of multiple gases and anaesthetic vapours comparing to the mainstream method that does not allow the measurement of other gases.

    • This question is part of the following fields:

      • Anaesthesia Related Apparatus
      25.8
      Seconds
  • Question 45 - A pulmonary function tests results are: (Measurement, Predicted result, Test result). Forced vital...

    Correct

    • A pulmonary function tests results are: (Measurement, Predicted result, Test result). Forced vital capacity (FVC) (btps): 3.85, 2.36 Forced expiratory volume in 1 second (FEV1) (btps): 3.34, 0.97. FEV1/FVC ratio % (btps): 85.1, 39.9. Peak expiratory flow (PEF) (L/second): 7.33, 2.11. Maximum voluntary ventilation (MVV) (L/minute): 116, 44.4. What does this indicate?

      Your Answer: Moderate restrictive and severe obstructive picture

      Explanation:

      Severity of a reduction in restrictive defect (%FVC) or obstructive defect (V1/FVC) predicted are classified as follows:

      Mild 70-80%
      Moderate 60-69%
      Moderately severe 50-59%
      Severe 35-49%
      Very severe <35%

      This patient has a mixed deficit with a severe obstructive deficit as V1/FVC predicted is 46.9% and a moderate restrictive deficit as %FVC of predicted is 61.3

      FEV1/FVC ratio 80% < predicted and VC < 80% = mixed picture.

      FEV1/FVC ratio 80% < predicted and VC > 80% = obstructive picture.

      FEV1/FVC ratio 80% > predicted and VC > 80% = normal picture.

      FEV1/FVC ratio 80% > predicted and VC < 80% predicted= restrictive picture.

    • This question is part of the following fields:

      • Clinical Measurement
      75
      Seconds
  • Question 46 - Of the stated laws, which is correct? ...

    Correct

    • Of the stated laws, which is correct?

      Your Answer: Boyle's law states that at constant temperature the volume of a given mass of gas varies inversely with absolute pressure.

      Explanation:

      Boyle’s law is correctly stated as it states that the volume of a gas of known mass is inversely proportional with absolute pressure, at a constant temperature.

      Beer’s law states that radiation absorption by a solution of known thickness and concentration is identical to that of a solution of double thickness and half concentration.

      Bougner’s (or Lambert’s) law states that every layer with the same thickness will absorb the same amount of radiation as it passes through.

      Graham’s law states that the diffusion rate of a gas is inversely related to the square root of its molecular weight.

      Raoult’s law states that the reduction of a solvent’s vapour pressure is directly proportional to the solute’s molar concentration.

    • This question is part of the following fields:

      • Statistical Methods
      5.8
      Seconds
  • Question 47 - Which term among the following is used for the proportion of a particular...

    Correct

    • Which term among the following is used for the proportion of a particular disease that would be eradicated from a population if the rate of disease were to be reduced to that of the group that has not been exposed to it?

      Your Answer: Attributable proportion

      Explanation:

      The attributable risk is the rate of a disease in an exposed group to that of a group that has not been exposed to it. It involves the measure of association that is pertinent to making decisions for the individuals.

    • This question is part of the following fields:

      • Statistical Methods
      32.6
      Seconds
  • Question 48 - Concerning the intercostal nerves, which one of the following is true? ...

    Incorrect

    • Concerning the intercostal nerves, which one of the following is true?

      Your Answer: The eleventh intercostal nerve is also known as the subcostal nerve

      Correct Answer: Each is connected to a ganglion of the sympathetic trunk

      Explanation:

      The intercostal nerves arise from the ventral rami of the first 11 thoracic spinal nerves. they course along the costal groove on the lower margin of the rib.

      The twelfth intercoastal nerve is called the subcostal nerve. This is because it is below the 12th rib.

      Each intercostal nerve is connected to a ganglion of the sympathetic trunk from which it carries preganglionic and postganglionic fibres that innervate blood vessels, sweat glands, and muscles.

      The lateral and medial pectoral nerves innervates pectoralis major muscle.

    • This question is part of the following fields:

      • Anatomy
      44.3
      Seconds
  • Question 49 - Among the following which one is not a criterion for the assessment of...

    Correct

    • Among the following which one is not a criterion for the assessment of causality?

      Your Answer: Sensitivity

      Explanation:

      For establishing a cause effect relationship, following criteria must be met:

      1. Coherence & Consistency

      2. Temporal Precedence

      3. Specificity

      As can be seen, sensitivity (The probability of a positive test) is not among these deciding factors..

    • This question is part of the following fields:

      • Statistical Methods
      34.6
      Seconds
  • Question 50 - The child-Pugh scoring system can be used, if risk classifying a patient with...

    Correct

    • The child-Pugh scoring system can be used, if risk classifying a patient with chronic liver disorder earlier to anaesthesia. Which one is the best combination of clinical signs and examinations used within the Child-Pugh scoring system?

      Your Answer: Ascites, grade of encephalopathy, albumin, bilirubin and INR

      Explanation:

      In the Child-Pugh classification system, the following 5 components are determined or calculated in order:

      Ascites

      Grade of encephalopathy

      Serum bilirubin (μmol/L)

      Serum Albumin (g/L)

      Prothrombin time or INR

      Raised liver enzymes are not the component of the classification system.

    • This question is part of the following fields:

      • Basic Physics
      23.8
      Seconds
  • Question 51 - A 20-year old male was involved in an accident and has presented to...

    Incorrect

    • A 20-year old male was involved in an accident and has presented to the Emergency Department with a pelvic crush injury. The clinical exam according to ATLS protocol revealed the following: Airway-patent, Breathing - respiratory rate 25 breaths per minute. Breath sounds are vesicular and there are no added sounds. Circulation - Capillary refill time - 4 seconds. Peripheries are cool. Pulse 125 beats/min. BP - 125/95 mmHg. Disability - GSC 15, anxious and in pain. Secondary survey reveals no other injuries. The patient is administered high flow oxygen and IV access is established. The most appropriate IV fluid regimen in this case will be which of the following?

      Your Answer: Transfuse crossmatched blood and products when available

      Correct Answer: Judicious infusion of Hartmann's solution to maintain a systolic blood pressure greater than 90mmHg

      Explanation:

      These clinical signs suggest that 15-30% of circulating blood volume has been lost.

      Pelvic fractures are associated with significant haemorrhage (>2000 ml) that can be concealed. This may require aggressive fluid resuscitation which is initially with crystalloids and then blood. What is also important is including stabilisation of the fracture(s) and pain relief.

      The Advanced Trauma Life Support (ATLS) classification of haemorrhagic shock is as follows:

      Class I haemorrhage (blood loss up to 15%):
      40% blood volume loss):
      Preterminal event patient will die in minutes
      Marked tachycardia, significant depression in systolic pressure and very narrow pulse pressure (or unobtainable diastolic pressure)
      Mental state is markedly depressed
      Skin cold and pale.
      Needs rapid transfusion and immediate surgical intervention.

      A blood loss of >50% results in loss of consciousness, pulse and blood pressure.

      Fluid resuscitation following trauma is a controversial area.

      This clinical scenario points to a 15-30% blood loss. However, further crystalloid and blood replacement may be required after assessing the clinical situation. There is increasing evidence to suggest that transfusion of large volumes of crystalloid in the hospital setting are likely to be deleterious to the patient and hypotensive resuscitation and judicious blood and blood product resuscitation is a more appropriate option. A ratio of 1 unit of plasma to 1 unit of red blood cells is used to replace fluid volume in adults.

      This patient does not require immediate transfusion of O negative blood and there is time for a formal crossmatch. The argument about colloids versus crystalloids has existed for decades. However, while they have a role in fluid resuscitation, they are not first line.

      There is a risk of anaphylaxis, Hypernatraemia, and acute renal injury with colloidal solutions.

    • This question is part of the following fields:

      • Physiology
      51
      Seconds
  • Question 52 - A 28-year-old girl, Sam, has suffered a road traffic accident. She is brought...

    Correct

    • A 28-year-old girl, Sam, has suffered a road traffic accident. She is brought to the emergency department and undergoes investigations and treatment. On X-ray of the humerus, she has a mid-shaft fracture. What structure is at the highest risk of damage with a mid-shaft humeral fracture?

      Your Answer: Radial nerve

      Explanation:

      Mid-shaft fractures of the humerus usually occur after a direct blow to the upper arm, which can occur after a fall or RTAs.
      The most important clinical significance of a mid-shaft humeral fracture is an injury to the radial nerve. The radial nerve originates from the brachial plexus and has roots of C5-T1. It crosses the spiral groove on the posterior side of the shaft of the humerus.
      On examination, the patient may have a wrist drop, loss or weakness of finger extension, and decreased or absent sensation to the posterior forearm, digits 1 to 3, and the radial half of the fourth digit.

      The humeral shaft has two compartments:
      1. Anterior:
      Brachial artery and vein
      Biceps brachii, brachialis, coracobrachialis
      Musculocutaneous, median, and ulnar nerves
      2. Posterior:
      Radial nerve
      Triceps

      Other significant nerve injuries are:
      1. Axillary nerve – surgical neck fracture of the humerus
      2. Brachial Artery – supracondylar fracture of the humerus
      3. Axillary artery – surgical neck fracture of the humerus, but is relatively uncommon.

    • This question is part of the following fields:

      • Anatomy
      17.2
      Seconds
  • Question 53 - How data is collected for the Delphi survey technique? ...

    Incorrect

    • How data is collected for the Delphi survey technique?

      Your Answer: Focus groups

      Correct Answer: Questionnaires

      Explanation:

      The Delphi is a group facilitation technique that seeks to obtain consensus on the opinions of `experts’ through a series of structured questionnaires (commonly referred to as rounds). By using successive questionnaires, opinions are considered in a non-adversarial manner, with the current status of the groups’ collective opinion being repeatedly fed back. Studies employing the Delphi make use of individuals who have knowledge of the topic being investigated

    • This question is part of the following fields:

      • Statistical Methods
      10.9
      Seconds
  • Question 54 - Which of the following nerves is responsible for relaying sensory information from the...

    Incorrect

    • Which of the following nerves is responsible for relaying sensory information from the laryngeal mucosa?

      Your Answer: Glossopharyngeal

      Correct Answer: Laryngeal branches of the vagus

      Explanation:

      Sensory innervation of the larynx is controlled by branches of the vagus nerve.

      The internal and external bifurcations of the superior laryngeal nerve is responsible for sensory innervation of the aspect of the larynx superior to the vocal cords, while the recurrent laryngeal nerve is responsible for sensory innervation of the intrinsic musculature of the larynx except for the cricothyroid muscle.

    • This question is part of the following fields:

      • Anatomy
      16.7
      Seconds
  • Question 55 - One of the non-pharmacologic management of COPD is smoking cessation. Given a case...

    Correct

    • One of the non-pharmacologic management of COPD is smoking cessation. Given a case of a 60-year old patient with history of smoking for 30 years and a FEV1 of 70%, what would be the most probable five-year course of his FEV1 if he ceases to smoke?

      Your Answer: The FEV1 will decrease at the same rate as a non-smoker

      Explanation:

      For this patient, his forced expiratory volume in 1 second (FEV1) will decrease at the same rate as a non-smoker.

      There is a notable, but slow, decline in FEV1 when an individual reaches the age of 26. An average reduction of 30 mls every year in non-smokers, while a more significant reduction of 50-70 mls is observed in approximately 20% of smokers.

      Considering the age of the patient, individuals who begin smoking cessation by the age of 60 are far less likely to achieve normal FEV1 levels, even in the next five years. It is expected that their FEV1 will be approximately 14% less than their peers of the same age.

    • This question is part of the following fields:

      • Physiology
      31
      Seconds
  • Question 56 - The population incidence of a disease is best described by? ...

    Correct

    • The population incidence of a disease is best described by?

      Your Answer: The number of new cases of a disease per population in a defined period

      Explanation:

      The incidence of a disease is the number of new cases of the disease in a population over a defined time period.

      The prevalence of a disease is the number of cases of the disease in a population over a defined time period describes. It is NOT the number of new cases.

      The number of new cases of a disease only, has no denominator (time period or population) from which to derive an incidence.

      The number of new cases of a disease seeking medical treatment is the incidence of patients seeking medical treatment NOT the incidence of the disease in a population.

      The death rate from a disease is the number of patients dying from the disease in a population.

    • This question is part of the following fields:

      • Statistical Methods
      16.6
      Seconds
  • Question 57 - You are approached by a drug rep who tells you about a new...

    Correct

    • You are approached by a drug rep who tells you about a new drug. The dosage and side effects of the drug are being determined in a trial. The representative asks you to refer participants for the trial. What type of participants should you refer? In which phase of trials is the drug currently in?

      Your Answer: Healthy participants, Phase 1

      Explanation:

      Phase 2 trials involve patients that are suffering from the disease under study and are associated with determining the efficiency and the optimum dosage of the drug.

      Phase 0 trials assist the scientists in studying the behaviour of drugs in humans by micro dosing patients. They are used to speed up the developmental process. They have no measurable therapeutic effect and efficiency.

      Phase 1 is associated with assessing whether a drug is safe to use or not. The process is extensive and can take up to several months. It also involves healthy participants (less than 100) that are paid to take part in the study. The side effects upon increasing dosage are also addressed by the study. The effects the drug has on humans including how its absorbed, metabolized and excreted are studied. Approximately 70% of the drugs pass this phase.

    • This question is part of the following fields:

      • Statistical Methods
      14.3
      Seconds
  • Question 58 - Which of the following statements is true with regards to acetylcholine? ...

    Incorrect

    • Which of the following statements is true with regards to acetylcholine?

      Your Answer: Edrophonium will make a myasthenic crisis worse and a cholinergic crisis better

      Correct Answer: Excess cholinesterase inhibitor medication causes cholinergic crisis

      Explanation:

      Myasthenic and cholinergic crises are two crises which are similar in their clinical presentation.

      Myasthenic crisis can be caused by:
      -lack of acetylcholine,
      -poor compliance with medication,
      -infection

      Cholinergic crisis can be caused by excess cholinesterase inhibitor medication (mimicking organophosphate poisoning) causing excess acetylcholine.

      Differentiation between the 2 crises is made by giving incremental doses of the short acting cholinesterase inhibitor, Edrophonium.
      This increase acetylcholine levels and will make a myasthenic crisis better and a cholinergic crisis worse.

    • This question is part of the following fields:

      • Physiology And Biochemistry
      32.2
      Seconds
  • Question 59 - Which of the following statement is true about Loop diuretics? ...

    Correct

    • Which of the following statement is true about Loop diuretics?

      Your Answer: Are useful in the treatment of acute heart failure

      Explanation:

      Loop diuretics act by causing inhibition of Na+ K+ 2Cl€“ symporter present at the luminal membrane of the ascending limb of the loop of Henle.

      Furosemide, torsemide, bumetanide, ethacrynic acid, furosemide, piretanide, tripamide, and mersalyl are the important members of this group

      The main use of loop diuretics is to remove the oedema fluid in renal, hepatic, or cardiac diseases. Thus they are useful in the treatment of acute heart failure. These can be administered i.v. for prompt relief of acute pulmonary oedema (due to vasodilatory action).

      Hypokalaemia, hypomagnesemia, hyponatremia, alkalosis, hyperglycaemia, hyperuricemia, and dyslipidaemia are seen with both thiazides as well as loop diuretics

    • This question is part of the following fields:

      • Pharmacology
      13.8
      Seconds
  • Question 60 - Prophylactic antibiotics are required for which of the following procedures? ...

    Correct

    • Prophylactic antibiotics are required for which of the following procedures?

      Your Answer: Appendicectomy

      Explanation:

      Staphylococcus aureus infection is the most likely cause.

      Surgical site infections (SSI) occur when there is a breach in tissue surfaces and allow normal commensals and other pathogens to initiate infection. They are a major cause of morbidity and mortality.

      SSI comprise up to 20% of healthcare associated infections and approximately 5% of patients undergoing surgery will develop an SSI as a result.
      The organisms are usually derived from the patient’s own body.

      Measures that may increase the risk of SSI include:
      -Shaving the wound using a single use electrical razor with a disposable head
      -Using a non iodine impregnated surgical drape if one is needed
      -Tissue hypoxia
      -Delayed prophylactic antibiotics administration in tourniquet surgery, patients with a prosthesis or valve, in clean-contaminated surgery of in contaminated surgery.

      Measures that may decrease the risk of SSI include:
      1. Intraoperatively
      – Prepare the skin with alcoholic chlorhexidine (Lowest incidence of SSI)
      -Cover surgical site with dressing

      In contrast to previous individual RCT’s, a recent meta analysis has confirmed that administration of supplementary oxygen does not reduce the risk of wound infection and wound edge protectors do not appear to confer benefit.

      2. Post operatively
      Tissue viability advice for management of surgical wounds healing by secondary intention

      Use of diathermy for skin incisions
      In the NICE guidelines the use of diathermy for skin incisions is not advocated. Several randomised controlled trials have been undertaken and demonstrated no increase in risk of SSI when diathermy is used.

    • This question is part of the following fields:

      • Physiology And Biochemistry
      10.5
      Seconds
  • Question 61 - Which of these anaesthetics has the best chance of preventing HPV (hypoxic pulmonary...

    Correct

    • Which of these anaesthetics has the best chance of preventing HPV (hypoxic pulmonary vasoconstriction)?

      Your Answer: Desflurane 2 MAC

      Explanation:

      Resistance pulmonary arteries constrict in response to alveolar and airway hypoxia, diverting blood to better-oxygenated alveoli.

      In atelectasis, pneumonia, asthma, and adult respiratory distress syndrome, hypoxic pulmonary vasoconstriction optimises O2 uptake. Hypoxic pulmonary vasoconstriction helps maintain systemic oxygenation during single-lung anaesthesia.

      A redox-based O2 sensor within pulmonary artery smooth muscle cells is involved in hypoxic pulmonary vasoconstriction. The production of reactive oxygen species by smooth muscle cells in the pulmonary artery varies in proportion to PaO2. Hypoxic removal of these redox second messengers inhibits voltage-gated potassium channels, depolarizing smooth muscle cells in the pulmonary artery.

      L-type calcium channels are activated by depolarization, which raises cytosolic calcium and causes hypoxic pulmonary vasoconstriction. Some anaesthetics suppress this response, increasing the risk of further deterioration in ventilation perfusion mismatch.

      Agents that inhibit HPV are ether, halothane, and desflurane (>1.6 MAC).
      Agents with no effect on HPV include thiopentone, fentanyl, desflurane (1MAC), isoflurane (<1.5MAC), sevoflurane(1MAC), and propofol.

    • This question is part of the following fields:

      • Pharmacology
      19
      Seconds
  • Question 62 - A balanced general anaesthetic including a muscle relaxant is administered at induction. It...

    Incorrect

    • A balanced general anaesthetic including a muscle relaxant is administered at induction. It is observed that the train-of-four count is two after two hours, with no further doses of the muscle relaxant. What is most likely reason for this?

      Your Answer: Vecuronium and gentamicin

      Correct Answer: Mivacurium with plasma cholinesterase deficiency

      Explanation:

      Mivacurium is metabolised primarily by plasma cholinesterase at an In vitro rate of about 70% that of succinylcholine. Mivacurium is contraindicated in patients with genetic and acquired plasma cholinesterase deficiencies.

      The clearance of atracurium is by Hoffman degradation and ester hydrolysis in the plasma and is independent of both hepatic and renal function.

      Rocuronium is eliminated primarily by the liver after metabolises to a less active metabolite, 17-desacetyl-rocuronium. Its duration of action is not affected much by renal impairment.

      Vecuronium undergoes hepatic metabolism into 3-desacetyl-vecuronium which has 50-80% the activity of the parent drug. It undergoes biliary (40%) and renal excretion (30%). The aminoglycoside antibiotics possess additional neuromuscular blocking activity. The potency of gentamicin > streptomycin > amikacin. Calcium can be used to reverse the muscle weakness produced by gentamicin but not neostigmine. When vecuronium and gentamycin are given together the effect on neuromuscular blockade is synergistic.

      Significant residual neuromuscular block 2 hours after the administration of these drugs is unlikely In this scenario.

      Any recovery from neuromuscular blockade with suxamethonium in a patient with deficiency of plasma cholinesterase demonstrate four twitches on a train of four count.

    • This question is part of the following fields:

      • Pharmacology
      74.2
      Seconds
  • Question 63 - The external laryngeal nerve is responsible for the innervation of which of the...

    Correct

    • The external laryngeal nerve is responsible for the innervation of which of the following muscles?

      Your Answer: Cricothyroid

      Explanation:

      The external laryngeal nerve arises from the superior laryngeal nerve and provides innervation to the cricothyroid muscle.

      The other muscles mentioned receive their innervations from the recurrent laryngeal nerve.

    • This question is part of the following fields:

      • Anatomy
      17.9
      Seconds
  • Question 64 - The structure most likely to be damaged during cannulation of the subclavian vein...

    Incorrect

    • The structure most likely to be damaged during cannulation of the subclavian vein is?

      Your Answer: Pleura

      Correct Answer: Subclavian artery

      Explanation:

      The subclavian artery lies behind and partly above the subclavian vein. 3-4% of the time, it can be inadvertently cannulated during cannulation of the subclavian vein

      Because of its anatomical position, putting pressure on the subclavian artery is impossible so arresting bleeding with pressure when it is punctured is not viable.

      One of the consequences of subclavian vein cannulation (1%) is pleural puncture leading to a pneumothorax. This is because the apical pleura is inferior and caudal to the subclavian vein.

    • This question is part of the following fields:

      • Anatomy
      21.2
      Seconds
  • Question 65 - A 76-year-old man, presents to his general practitioner with a lump in his...

    Correct

    • A 76-year-old man, presents to his general practitioner with a lump in his left groin. Upon examination, his doctor is able to diagnose a direct inguinal hernia. There are many structures present in the inguinal canal. Where is the ilioinguinal nerve located in relation to the spermatic cord?

      Your Answer: Anterior to the spermatic cord

      Explanation:

      The answer is anterior to the spermatic cord.

      The inguinal canal in men contains the ilioinguinal nerve, the genitofemoral nerve and the spermatic cord.

      The ilioinguinal nerve arises of the L1 nerve root with the Iliohypogastric nerve, before entering the inguinal canal from the side, through the muscles of the abdomen, travelling superficial to the spermatic cord.

    • This question is part of the following fields:

      • Anatomy
      22.1
      Seconds
  • Question 66 - Which structure passes through the foramen magnum? ...

    Correct

    • Which structure passes through the foramen magnum?

      Your Answer: Spinal roots of the accessory nerve

      Explanation:

      The structures that pass through the foramen magnum are:

      Meningeal lymphatics
      Spinal cord
      Spinal meninges
      Sympathetic plexus of vertebral arteries
      Vertebral arteries
      Vertebral artery spinal branches
      The spinal roots of the accessory nerve.

      The jugular foramen contains the vagus nerve, the accessory nerve and glossopharyngeal nerve.

      The vertebral veins does not pass into the skull.

    • This question is part of the following fields:

      • Anatomy
      10
      Seconds
  • Question 67 - Modified rapid sequence induction with 1mg/kg rocuronium was done is a 42-year-old male...

    Correct

    • Modified rapid sequence induction with 1mg/kg rocuronium was done is a 42-year-old male for emergency appendicectomy. The patient weight was 70 kg and a failed intubation indicated immediate reversal of neuromuscular blockade. Which of the following is the correct dose of sugammadex for this patient?

      Your Answer: 1120 mg

      Explanation:

      Sugammadex is used for immediate reversal of rocuronium-induced neuromuscular blockade.
      It is used at a dose of 16 mg/kg.

      Since the patient in the question is 70 kg, the required dose of sugammadex can be calculated as:
      16×70 = 1120 mg.

      Sugammadex selectively binds rocuronium or vecuronium, thereby reversing their neuromuscular blocking action. Due to its 1:1 binding of rocuronium or vecuronium, it can reverse any depth of neuromuscular block.

    • This question is part of the following fields:

      • Pharmacology
      19
      Seconds
  • Question 68 - At 37 weeks' gestation, a 29-year-old parturient is admitted to the labour ward....

    Correct

    • At 37 weeks' gestation, a 29-year-old parturient is admitted to the labour ward. Her antenatal period was asymptomatic for her. The haematological values listed below are available: Hb concentration of 100 g/L (115-165), 200x109/L platelets (150-400), MCV 81 fL (80-96). Which of the following is the most likely reason for the problem?

      Your Answer: Iron deficiency

      Explanation:

      This patient’s limited haematological profile includes mild normocytic anaemia and a normal platelet count.

      Iron deficiency is the most common cause of anaemia during pregnancy. It affects 75 to 95 percent of patients. A haemoglobin level of less than 110 g/L in the first trimester and less than 105 g/L in the second and third trimesters is considered anaemia. There will usually be a low mean cell volume (MCV), mean cell haemoglobin (MCH), and mean cell haemoglobin concentration in addition to a low haemoglobin (MCHC). The MCV may be normal in mild cases of iron deficiency or coexisting vitamin B12 and folate deficiency.

      To determine whether you have an iron deficiency, you’ll need to take more tests. Low serum ferritin (15 g/L) and less reliable indices like serum iron and total iron binding capacity are among them.

      A number of factors contribute to iron deficiency in pregnancy, including:

      Insufficient dietary iron to meet the mother’s and foetus’ nutritional needs
      Multiple pregnancies
      Blood loss, as well as
      Absorption of iron from the gut is reduced.

      The volume of plasma increases by about 50% during pregnancy, but the mass of red blood cells (RBCs) increases by only 30%. Dilutional anaemia is the result of this situation. From the first trimester to delivery, the RBC mass increases linearly, while the plasma volume plateaus, stabilises, or falls slightly near term. As a result, between 28 and 34 weeks of pregnancy, haemoglobin concentrations are at their lowest. The effects of haemodilution will be negated in this patient because she is 37 weeks pregnant.

      Vitamin B12 and folate deficiency are less common causes of anaemia in pregnancy. The diagnosis could be ruled out if the MVC is normal.

      During pregnancy, the platelet count drops, especially in the third trimester. Gestational thrombocytopenia is the medical term for this condition. It’s due to a combination of factors, including haemodilution and increased platelet activation and clearance. Pre-eclampsia and HELLP syndrome are common causes of thrombocytopenia. Pre-eclampsia isn’t the only cause of anaemia during pregnancy.

      A typical blood picture of a haemoglobinopathy like sickle cell disease shows quantitative and qualitative defects, with the former leading to a severe anaemia exacerbated by haemodilution and other factors that contribute to iron deficiency. Microcytic cells are the most common type.

    • This question is part of the following fields:

      • Pathophysiology
      13.9
      Seconds
  • Question 69 - What statement about endotoxins is true? ...

    Correct

    • What statement about endotoxins is true?

      Your Answer: Can often survive autoclaving

      Explanation:

      Endotoxins are the lipopolysaccharides found in the outer cell wall of Gram-negative bacteria. They are responsible for providing the structure and stability of the cell wall.

      They cannot be destroyed by normal sterilisation as they are heat stable molecules. They require the use of certain sterilant such as superoxide, peroxide and hypochlorite to be neutralised.

      They stimulate strong immune responses, but can only be destroyed partially by specific antibodies. Repeat infections occur as memory T cells cannot be formed.

      It can cause septicaemia and associated symptoms such as fever, shock, hypotension and nausea.

      It activates the alternative complement pathway and the coagulation pathway using secreted cytokines.

      It is not involved in botulism as clostridium botulinum, the responsible organism, secretes a neurotoxic exotoxin.

    • This question is part of the following fields:

      • Pathophysiology
      12.4
      Seconds
  • Question 70 - Which of the following is the best associated option with Kaplan-Meier survival plot?...

    Correct

    • Which of the following is the best associated option with Kaplan-Meier survival plot?

      Your Answer: An estimate of decreasing survival with time after an event.

      Explanation:

      Also known as the €œproduct limit estimate”, the Kaplan-Meier survival plot is used to estimate the true survival function from the collected data.

      Using this plot, probabilities of occurrence of an event at a certain point in time can be computed. The successive probabilities are multiplied by any earlier computed probabilities to get the final estimate. For a given population, the survival probability at any particular time on the plot = (number of subjects living at the start – number of subjects who died)/number of subjects living at the start.

      The description of a scatter plot is a graphical representation using Cartesian coordinates to display values for more than two variables for data set. It is used for to assess the relationship between 2 different variables.

    • This question is part of the following fields:

      • Statistical Methods
      9
      Seconds
  • Question 71 - Of the following, which option best describes the muscle type that has the...

    Correct

    • Of the following, which option best describes the muscle type that has the fastest twitch response to stimulation?

      Your Answer: Type IIb skeletal muscle

      Explanation:

      Human skeletal muscle is composed of a heterogeneous collection of muscle fibre types which differ histologically, biochemically and physiologically.

      It can be biochemically classified into 2 groups. This is based on muscle fibre myosin ATPase histochemistry. These are:

      Type 1 (slow twitch): Muscle fibres depend upon aerobic glycolytic metabolism and aerobic oxidative metabolism. They are rich in mitochondria, have a good blood supply, rich in myoglobin and are resistant to fatigue.

      Type II (fast twitch): Muscle fibres are sub-divided into:
      Type IIa – relies on aerobic/oxidative metabolism
      Type IIb – relies on anaerobic/glycolytic metabolism.

      Fast twitch muscle fibres produce short bursts of power but are more easily fatigued.

      Cardiac and smooth muscle twitches are relatively slow compared with skeletal muscle.

    • This question is part of the following fields:

      • Physiology
      17
      Seconds
  • Question 72 - A 21-year-old woman presents to ER following the deliberate ingestion of 2 g...

    Correct

    • A 21-year-old woman presents to ER following the deliberate ingestion of 2 g of amitriptyline. On clinical examination: Glasgow coma score: 10, Pulse rate: 140 beats per minute, Blood pressure: 80/50 mmHg. ECG showed a QRS duration of 233 Ms. Which of the following statement describes the most important initial course of action?

      Your Answer: Give fluid boluses

      Explanation:

      The first line of treatment in case of hypotension is fluid resuscitation.

      Activated charcoal can be used within one hour of tricyclic antidepressant ingestion but an intact and secure airway must be checked before intervention. The risk of aspiration should be assessed.

      Vasopressors are indicated for the treatment of hypotension following (Tricyclic Antidepressant) TCA overdose when patients fail to respond to fluids and bicarbonate.

    • This question is part of the following fields:

      • Pharmacology
      40.8
      Seconds
  • Question 73 - A trail has analysed that a new screening test may increase the survival...

    Correct

    • A trail has analysed that a new screening test may increase the survival time of ovarian cancer patients. But analyst say that the apparent increase in the patients survival time is just because of earlier detection instead of actual improvement. What kind of bias is in this experiment?

      Your Answer: Lead time bias

      Explanation:

      Observation bias occurs when the behaviour of an individual changes that results from their awareness of being observed.

      Recall bias introduced when participants in a study are systematically more or less likely to recall and relate information on exposure depending on their outcome status.

      Attrition bias is a systematic error caused by unequal loss of participants from a randomized controlled trial (RCT). In clinical trials, participants might dropout due to unsatisfactory treatment or efficacy, intolerable adverse events, or even death.

      Selection bias introduced when the individuals are not chosen randomly to take a part in the study. It usually occurs when the research decides who is going to be studied, they are not the representative of the population.

      Lead-time bias occurs when a disease is detected by a screening test at an earlier time point rather than it would have been diagnosed by its clinical appearance. In this bias, earlier detection improves the survival time in the intervention group.

    • This question is part of the following fields:

      • Statistical Methods
      9.5
      Seconds
  • Question 74 - Which of the following statement is not true regarding soda lime? ...

    Incorrect

    • Which of the following statement is not true regarding soda lime?

      Your Answer: The formation of calcium carbonate requires heat

      Correct Answer: Silica is added to prevent disintegration of the granules

      Explanation:

      Soda-lime contains mostly calcium hydroxide (about 94%) and the remaining sodium hydroxide.

      CO2 + Ca(OH)2 †’ CaCO3 + H2O + heat
      Here in this exothermic reaction, we can see that the production of calcium carbonate does not require heat.

      When soda lime is allowed to dry with subsequent use of desflurane, isoflurane, and enflurane, it can lead to the generation of carbon monoxide.

      Silicated hardens the granules and can thus prevent disintegration.

      The size of soda-lime granules is 4-8 mesh because it allows sufficient surface area for chemical reaction to occur without critically increasing the resistance to airflow.

    • This question is part of the following fields:

      • Pharmacology
      62.2
      Seconds
  • Question 75 - Regarding the plateau phase of the cardiac potential, which electrolyte is the main...

    Correct

    • Regarding the plateau phase of the cardiac potential, which electrolyte is the main determinant?

      Your Answer: Ca2+

      Explanation:

      The cardiac action potential has several phases which have different mechanisms of action as seen below:
      Phase 0: Rapid depolarisation – caused by a rapid sodium influx.
      These channels automatically deactivate after a few ms

      Phase 1: caused by early repolarisation and an efflux of potassium.

      Phase 2: Plateau – caused by a slow influx of calcium.

      Phase 3 – Final repolarisation – caused by an efflux of potassium.

      Phase 4 – Restoration of ionic concentrations – The resting potential is restored by Na+/K+ATPase.
      There is slow entry of Na+into the cell which decreases the potential difference until the threshold potential is reached. This then triggers a new action potential

      Of note, cardiac muscle remains contracted 10-15 times longer than skeletal muscle.

      Different sites have different conduction velocities:
      1. Atrial conduction – Spreads along ordinary atrial myocardial fibres at 1 m/sec

      2. AV node conduction – 0.05 m/sec

      3. Ventricular conduction – Purkinje fibres are of large diameter and achieve velocities of 2-4 m/sec, the fastest conduction in the heart. This allows a rapid and coordinated contraction of the ventricles

    • This question is part of the following fields:

      • Physiology
      7.7
      Seconds
  • Question 76 - All of the following statements about intravenous induction agents are false except: ...

    Correct

    • All of the following statements about intravenous induction agents are false except:

      Your Answer: Barbiturates include thiopental and methohexitone.

      Explanation:

      Thiopental is a new British Approved Name for thiopentone and is thio-barbiturate.
      Methohexitone is an oxy- barbiturate. Both thiopental and methohexitone are intravenous induction agents.

      Ketamine cannot cause loss of consciousness in less than 30 seconds. At least 30 seconds is needed to cause loss of consciousness following intravenous administration.

      Etomidate is an imidazole but it is not used on Intensive therapy unit for sedation because it has an antidepressant effect on the steroid axis.

    • This question is part of the following fields:

      • Pharmacology
      61.6
      Seconds
  • Question 77 - A 45-year old gentleman is in the operating room to have a knee...

    Correct

    • A 45-year old gentleman is in the operating room to have a knee arthroscopy under general anaesthesia. Induction is done using fentanyl 1mcg/kg and propofol 2mg/kg. A supraglottic airway is inserted and the mixture used to maintain anaesthesia is and air oxygen mixture and 2.5% sevoflurane. Using a Bain circuit, the patient breathes spontaneously and the fresh gas flow is 9L/min. Over the next 30 minutes, the end-tidal CO2 increase from 4.5kPa to 8.4kPa, and the baseline reading on the capnograph is 0kPa. The most appropriate action that should follow is:

      Your Answer: Observe the patient for further change

      Explanation:

      Such a high rise of end-tidal CO2 (EtCO2) in a patient who is spontaneously breathing is often encountered.

      Close observation should occur for further rises in EtCO2 and other signs of malignant hyperthermia. If this were to rise even more, it might be wise to ensure that ventilatory support is available.

      A lot would depend on whether surgery was almost completed. At this stage of anaesthesia, it would be inappropriate to administer opioid antagonists or respiratory stimulants.

    • This question is part of the following fields:

      • Physiology
      50.2
      Seconds
  • Question 78 - A 20-year-old woman, presented to her GP after swallowing a tiny, sharp bone...

    Correct

    • A 20-year-old woman, presented to her GP after swallowing a tiny, sharp bone and is referred to an ENT. She explains that the bone feels stuck in her throat. A laryngoscopy is performed and it shows the bone is lodged in the piriform recess. Name the nerve at highest risk of damage by the bone?

      Your Answer: Internal laryngeal nerve

      Explanation:

      The internal laryngeal nerve lies inferior to the piriform recess mucous membrane, placing it at high risk of irritation or damage by sharp foreign objects which become lodged in the recess.

      Any attempt to retrieve lodged foreign objects must be done careful as there is also a high risk of damage during this process.

      The other mentioned nerves are not at risk of being affected.

    • This question is part of the following fields:

      • Anatomy
      23.7
      Seconds
  • Question 79 - A 27-year-old woman takes part in a study looking into the effects of...

    Correct

    • A 27-year-old woman takes part in a study looking into the effects of different dietary substrates on metabolism. She receives a 24-hour ethyl alcohol infusion. A constant volume, closed system respirometer is used to measure CO2 production and consumption. The production of carbon dioxide is found to be 200 mL/minute. Which of the following values most closely resembles her anticipated O2 consumption at the conclusion of the trial?

      Your Answer: 300 mL/minute

      Explanation:

      The respiratory quotient (RQ) is the ratio of CO2 produced by the body to O2 consumed in a given amount of time.

      CO2 produced / O2 consumed = RQ

      CO2 is produced at a rate of 200 mL per minute, while O2 is consumed at a rate of 250 mL per minute. An RQ of around 0.8 is typical for a mixed diet.

      The RQ will change depending on the energy substrates consumed in the diet. Granulated sugar is a refined carbohydrate that contains 99.999 percent carbohydrate and no lipids, proteins, minerals, or vitamins.

      Glucose and other hexose sugars (glucose and other hexose sugars):
      RQ=1

      Fats:
      RQ = 0.7

      Proteins:
      Approximately 0.9 RQ

      Ethyl alcohol is a type of alcohol.

      200/300 = 0.67 RQ

      For complete oxidation, lipids and alcohol require more oxygen than carbohydrates.

      When carbohydrate is converted to fat, the RQ can rise above 1.0. Fat deposition and weight gain are likely to occur in these circumstances.

    • This question is part of the following fields:

      • Physiology
      73.2
      Seconds
  • Question 80 - An orthopaedic surgery is scheduled for a 68-year-old man. He is normally in...

    Incorrect

    • An orthopaedic surgery is scheduled for a 68-year-old man. He is normally in good shape. His routine biochemistry results are checked and found to be within normal limits. Which of the following pairs has the greatest impact on his plasma osmolarity?

      Your Answer: Glucose and urea molecules

      Correct Answer: Sodium and potassium cations

      Explanation:

      The number of osmoles (Osm) of solute per litre (L) of solution (Osmol/L) is the unit of measurement for solute concentration. The calculated serum osmolality assumes that the primary solutes in the serum are sodium salts (chloride and bicarbonate), glucose, and urea nitrogen.

      2 (Na + K) + Glucose + Urea (all in mmol/L) = calculated osmolarity

      313 mOsm/L = 2 (144 + 6) + 9.5 + 3.5

      Sodium and potassium ions clearly contribute the most to plasma osmolarity. Glucose and urea, on the other hand, are less so.

      The osmolarity of normal serum is 285-295 mOsm/L. Temperature and pressure affect osmolality, and this calculated variable is less than osmolality for a given solution.

      The number of osmoles (Osm) of solute per kilogramme (Osm/kg) is a measure of osmolality, which is also a measure of solute concentration. Temperature and pressure have no effect on the value. An osmometer is used to measure it in the lab. Osmometers rely on a solution’s colligative properties, such as a decrease in freezing point or a rise in vapour pressure.

      The osmolar gap (OG) is calculated as follows:

      OG = osmolaRity calculated from measured serum osmolaLity

      Excess alcohols, lipids, and proteins in the blood can all contribute to the difference.

    • This question is part of the following fields:

      • Physiology
      35
      Seconds
  • Question 81 - Which of the following statement is not true regarding Adrenaline or Epinephrine? ...

    Incorrect

    • Which of the following statement is not true regarding Adrenaline or Epinephrine?

      Your Answer: Inhibits Insulin secretion

      Correct Answer: Inhibits Glucagon secretion in the pancreas

      Explanation:

      Adrenaline acts on α1, α2, β1, and β2 receptors and also on dopamine receptors (D1, D2) and have sympathomimetic effects.

      Natural catecholamines are Adrenaline, Noradrenaline, and Dopamine

      Adrenaline is a sympathomimetic amine with both alpha and beta-adrenergic stimulating properties.
      Adrenaline is the drug of choice for anaphylactic shock
      Adrenaline is also used in patients with cardiac arrest. The preferred route is i.v. followed by the intra-osseous and endotracheal route.

      Adrenaline is released by the adrenal glands, acts on α 1 and 2, β 1 and 2 receptors, and is responsible for fight or flight response.

      It acts on β 2 receptors in skeletal muscle vessels-causing vasodilation.

      It acts on α adrenergic receptors to inhibit insulin secretion by the pancreas. It also stimulates glycogenolysis in the liver and muscle, stimulates glycolysis in muscle.

      It acts on β adrenergic receptors to stimulate glucagon secretion in the pancreas. It also stimulates Adrenocorticotrophic Hormone (ACTH) and stimulates lipolysis by adipose tissue

    • This question is part of the following fields:

      • Pharmacology
      30.9
      Seconds
  • Question 82 - A 67-year-old man, presents with an embolus in the lower limbs. He has...

    Correct

    • A 67-year-old man, presents with an embolus in the lower limbs. He has previous medical history of atrial fibrillation. After examination and diagnostic investigations, he is scheduled for a transpopliteal embolectomy, which will require the surgeons to explore the central region of the popliteal fossa. What structures will the surgeons come across after incising the deep fascia?

      Your Answer: Tibial nerve

      Explanation:

      The tibial nerve lies on top of the vessels contained within the inferior aspect of the popliteal fossa.

      In the superior aspect of the fossa, the tibial nerve runs lateral to the vessels, before then travelling superficial to the vessels, and then finally changing course to lie medial to the vessels.

      The popliteal artery is the most deep structure present in the popliteal fossa.

    • This question is part of the following fields:

      • Anatomy
      40.1
      Seconds
  • Question 83 - 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
      36.7
      Seconds
  • Question 84 - A 40-year-old obese woman has complaints of heartburn and regurgitation that is worse...

    Correct

    • A 40-year-old obese woman has complaints of heartburn and regurgitation that is worse on lying flat. The doctor suspects gastroesophageal reflux due to a hiatus hernia. Lifestyle modifications to lose weight and antacids are prescribed to her. At which level of the diaphragm will you find an opening for this problem?

      Your Answer: T10

      Explanation:

      Hiatus is an opening in the diaphragm. A hiatal hernia is a protrusion of the upper part of the stomach through an opening in the diaphragm, the oesophageal hiatus, into the thorax. The oesophageal hiatus occurs at the level of T10 in the right crus of the diaphragm.

      Other important openings in the diaphragm:
      T8: vena cava, terminal branches of the right phrenic nerve
      T10: oesophagus, vagal trunks, left anterior phrenic vessels, oesophageal branches of the left gastric vessels
      T12: descending aorta, thoracic duct, azygous and hemi-azygous vein

      An opening in the diaphragm is called a hiatus. The oesophageal hiatus is at vertebral level T10. A hiatus hernia is where the stomach bulges through the oesophageal hiatus hence the name – hiatus hernia.

    • This question is part of the following fields:

      • Anatomy
      9.2
      Seconds
  • Question 85 - The prostate and the rectum are separated by which anatomical plane? ...

    Incorrect

    • The prostate and the rectum are separated by which anatomical plane?

      Your Answer: Levator ani muscle

      Correct Answer: Denonvilliers fascia

      Explanation:

      The prostate is separated from the rectum by the Denonvilliers fascia (rectoprostatic fascia).

      Waldeyers fascia functions to separate the rectum and the sacrum.

    • This question is part of the following fields:

      • Anatomy
      13.1
      Seconds
  • Question 86 - Over the course of 10 minutes, one litre of 0.9% normal saline is...

    Correct

    • Over the course of 10 minutes, one litre of 0.9% normal saline is intravenously infused into a normally fit and well 58-year-old male. A catheter is used to measure urine output before and after the infusion. The patient is 70 kg in weight. The following data on urine output is obtained: 50ml/hour Before the infusion, 200 ml/hour 1 hour following infusion, 90 ml/hour 2 hours after the infusion, 60 ml/hr 3 hours after the infusion. Which of the following physiological responses is most likely to account for the sudden increase in urine output after a fluid bolus?

      Your Answer: Increased glomerular filtration rate

      Explanation:

      The following are some basic assumptions:

      Extracellular fluid (ECF) makes up one-third of total body water (TBW), while intracellular fluid makes up the other two-thirds (ICF).
      One-quarter of ECF is plasma, and three-quarters is interstitial fluid (ISF).
      The volume receptors have a 7-10% blood volume change threshold. The osmoreceptors are sensitive to changes in osmolality of 1-2 percent.
      Prior to the transfusion, the plasma osmolality is normal (between 287 and 290 mOsm/kg).
      [Na+] in 0.9 percent N. saline is 154 mmol/L, which is similar to that of extracellular fluid. When given intravenously, this limits its distribution within the extracellular space, resulting in a plasma compartment:ISF volume ratio of 1:3.
      In this time frame, one litre of 0.9 percent N. saline will increase plasma volume by about 250 mL, which could be the threshold for activation of the volume receptors in the atria, resulting in the release of atrial natriuretic peptide (ANP).

      Because 0.9 percent N. saline is isosmotic, after a 1 L infusion, plasma osmolality will not change. No changes in antidiuretic hormone secretion will be detected by the hypothalamic osmoreceptors.

      Because normal saline is protein-free, the oncotic pressure in the blood is slightly reduced after the saline infusion. As a result, fluid movement into the ISF is favoured (Starling’s hypothesis), and the lower oncotic pressure causes an immediate increase in the glomerular filtration rate (GFR) and a reduction in water reabsorption in the proximal tubule.

      The flow of urine increases. There is no hormonal intermediary in this effect, so it is strictly local. Urine flow immediately increases. The fluid returns to the intravascular compartment, and urine flow continues until all of the transfused fluid has been excreted.

      Blood pressure changes associated with a 1 L fluid infusion are unlikely to affect high-pressure baroreceptors in the carotid sinus.

      The juxta-glomerular cells of the afferent arteriole are adjacent to the specialised cells (macula densa) of distal tubules. The sodium and chloride ions in the tubular fluid are detected by the macula densa. Renin release is inhibited when the tubular fluid contains too much sodium chloride. Hormonal changes take longer to manifest than physical changes that control glomerulotubular balance.
      Hypertonic saline, not 0.9 percent N saline, is an osmotic diuretic.

    • This question is part of the following fields:

      • Pathophysiology
      35.2
      Seconds
  • Question 87 - The statement that best describes the classification of theatre equipment in terms of...

    Correct

    • The statement that best describes the classification of theatre equipment in terms of electrical safety is:

      Your Answer: A floating circuit is equipment applied to patient that is isolated from all its other parts

      Explanation:

      There are different classes of electrical equipment that can be classified in the table below:

      Class 1 – provides basic protection only. It must be connected to earth and insulated from the mains supply

      Class II – provides double insulation for all equipment. It does not require an earth.

      Class III – uses safety extra low voltage (SELV) which does not exceed 24 V AC. There is no risk of gross electrocution but risk of microshock exists.

      Type B – All of above with low leakage currents (0.5mA for Class IB, 0.1 mA for Class IIB)

      Type BF – Same as with other equipment but has ‘floating circuit’ which means that the equipment applied to patient is isolated from all its other parts.

      Type CF – Class I or II equipment with ‘floating circuits’ that is considered to be safe for direct connection with the heart. There are extremely low leakage currents (0.05mA for Class I CF and 0.01mA for Class II CF).

    • This question is part of the following fields:

      • Clinical Measurement
      45.5
      Seconds
  • Question 88 - An study on post-operative nausea and vomiting (PONV) among paediatric patients who underwent...

    Correct

    • An study on post-operative nausea and vomiting (PONV) among paediatric patients who underwent tonsillectomy showed a decrease in incidence from 10% to 5% following a new management protocol. Which of the following best estimates the numbers needed to treat (NNT) for one additional patient to benefit from the new management of PONV?

      Your Answer: 20

      Explanation:

      The Number Needed to Treat (NNT) is the number of patients you need to treat to prevent one additional bad outcome. For example, if a drug has an NNT of 5, it means you have to treat 5 people with the drug to prevent one additional bad outcome.

      To calculate the NNT, you need to know the Absolute Risk Reduction (ARR); the NNT is the inverse of the ARR:

      NNT = 1/ARR

      Where ARR = CER (Control Event Rate) €“ EER (Experimental Event Rate).

      NNTs are always rounded up to the nearest whole number.

      In this case, the NNT can be computed as follows:

      ARR = 10% – 5% = 0.05

      NNT = 1/0.05 = 20

    • This question is part of the following fields:

      • Statistical Methods
      34.3
      Seconds
  • Question 89 - Regarding thyroid hormones, one of the following is true. ...

    Correct

    • Regarding thyroid hormones, one of the following is true.

      Your Answer: Thyroid binding globulin (TBG) is increased in pregnancy

      Explanation:

      T3 is produced by peripheral de-iodination of T4. It is more active than T4.

      TBG, like most binding proteins, is increased in pregnancy. Because of this, measurement of free thyroid hormone concentration is more important than total.

      T4 and T3 concentrations are decreased in Illness and starvation.

      L-T4 that is the active molecule while D-T4 is inactive.

    • This question is part of the following fields:

      • Pathophysiology
      12.9
      Seconds
  • Question 90 - A 62-year-old woman, presents to emergency department with an ischaemic left colon. Multiple...

    Correct

    • A 62-year-old woman, presents to emergency department with an ischaemic left colon. Multiple arteries arise from the aorta at the level of the L3 vertebrae, which is most likely to be involved in this pathology?

      Your Answer: Inferior mesenteric artery

      Explanation:

      The inferior mesenteric artery arises from the abdominal aorta at the level of the L3 vertebrae and supplies blood to the final third of the transverse colon, the descending colon, the sigmoid colon and the uppermost part of the rectum.

      It is the artery most likely to affect the left colon.

    • This question is part of the following fields:

      • Anatomy
      22.9
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Pharmacology (11/17) 65%
Pathophysiology (5/10) 50%
Basic Physics (2/3) 67%
Anatomy (12/20) 60%
Physiology And Biochemistry (1/3) 33%
Clinical Measurement (4/6) 67%
Physiology (10/14) 71%
Statistical Methods (13/14) 93%
Anaesthesia Related Apparatus (3/3) 100%
Passmed