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  • Question 1 - A 58-year-old man is being operated on for a radical gastrectomy for carcinoma...

    Incorrect

    • A 58-year-old man is being operated on for a radical gastrectomy for carcinoma of the stomach. Which structure needs to be divided to gain access to the coeliac axis?

      Your Answer: Gastrosplenic ligament

      Correct Answer: Lesser omentum

      Explanation:

      The lesser omentum will need to be divided. This forms one of the nodal stations that will need to be taken during a radical gastrectomy.

      The celiac axis is the first branch of the abdominal aorta and supplies the entire foregut (mouth to the major duodenal papilla). It arises at the level of vertebra T12. It has three major branches:
      1. Left gastric
      2. Common hepatic
      3. Splenic arteries.

    • This question is part of the following fields:

      • Anatomy
      11.1
      Seconds
  • Question 2 - Provided below is an abstract of a study conducted recently. A consensus was...

    Incorrect

    • Provided below is an abstract of a study conducted recently. A consensus was developed among international experts. A total of 27 experts were invited. 91% of them decided to show up. A systematic review was performed. This comprised of open ended questions and the participants were encouraged to provide suggestions by e-mail. In the second phase google forms were used. Participants were asked to rate survey items on a scale of 5 points. Items that were rated critical by no less than 80% of the experts were included. Items that were rendered important by 65-79% of experts were inducted in the next survey for re rating. Items that were rated below 65% were rejected. Which of the following methods was used in the study from which the abstract has been taken?

      Your Answer: Triangulation

      Correct Answer: The Delphi method

      Explanation:

      The process used in the study is Delphi method. This method kicks off with an open ended questionnaire and uses its responses as a survey instrument for the next round in which each of the participants is asked to rate the items that the investigators have summarized on the basis of the data collected in the first round.

      Any disagreement is further discussed in phases to come on the basis of information obtained from previous phases.

    • This question is part of the following fields:

      • Statistical Methods
      24.4
      Seconds
  • Question 3 - Which of the following does Lidocaine 1% solution equate to? ...

    Correct

    • Which of the following does Lidocaine 1% solution equate to?

      Your Answer: 1000 mg per 100 ml

      Explanation:

      Lidocaine 1% is formulated either as 1000 mg/100 mL or 100 mg/1mL.

    • This question is part of the following fields:

      • Pharmacology
      149.8
      Seconds
  • Question 4 - Which of the following statements is true about oxygen face masks? ...

    Incorrect

    • Which of the following statements is true about oxygen face masks?

      Your Answer:

      Correct Answer: The oxygen concentration delivered by high air flow oxygen enrichment devices is not dependent on the respiratory pattern of the patient

      Explanation:

      The normal peak inspiratory flow in healthy individuals is 20-30 L/min during each normal tidal ventilation. This is expected to increase with greater respiratory rate and deeper inspiration.

      Face masks are used to facilitate the delivery of oxygen from a breathing system to a patient. Face masks can be divided into two types: fixed performance or variable performance devices.

      In fixed performance devices (also known as high air flow oxygen enrichment or HAFOE), fixed inspired oxygen concentration is delivered to the patent, independent and greater than that of the patient’s peak inspiratory flow rate (PIFR). No random entrainment is expected to occur at the time of PIFR, hence, the oxygen concentration in HAFOE devices is not dependent on the patient’s respiratory pattern.

      Moreover, in HAFOE masks, the concentration of oxygen at a given oxygen flow rate is determined by the size of the constriction; a device with a greater entrainment aperture delivers a lower oxygen concentration. Therefore, a 40% Venturi device will have lesser entrainment aperture when compared to a 31% Venturi. Venturi masks allow relatively fixed concentrations of supplemental oxygen to be inspired e.g. 24%, 28%, 31%, 35%, 40% and 60% oxygen. These are colour coded and marked with the recommended oxygen flow rate.

      Variable performance devices deliver variable inspired oxygen concentration to the patient, and is dependent on the PIFR. The PIFR can often exceed the flow rate at which oxygen or an oxygen/air mixture is supplied by the device, depending on a patient’s inspiratory effort. In addition, these masks allow expired air to be released through the holes in the sides of the mask. Thus, with increased respiratory rate, rebreathing of alveolar gas from inside the mask may occur.

    • This question is part of the following fields:

      • Anaesthesia Related Apparatus
      0
      Seconds
  • Question 5 - The phenomenon that the patients behaved in a different manner when they know...

    Incorrect

    • The phenomenon that the patients behaved in a different manner when they know that they are being observed is termed as?

      Your Answer:

      Correct Answer: Hawthorne effect

      Explanation:

      Hawthorne effect explains the change in any behavioural aspect owing to the awareness that the person is being observed.
      Simpson’s Paradox explains the association developed when the data from several groups is combined to form a single larger group.

      The remaining terms are made up.

    • This question is part of the following fields:

      • Statistical Methods
      0
      Seconds
  • Question 6 - Regarding gas laws, which one best explains the ability of a Bourdon gauge...

    Incorrect

    • Regarding gas laws, which one best explains the ability of a Bourdon gauge to measure temperature?

      Your Answer:

      Correct Answer: Charles's law

      Explanation:

      Charles’ Law states that there is a direct correlation between temperature and volume, where pressure and amount gas are constant. As temperature increases, volume also increases.

      Boyle’s Law states that Pressure is inversely proportional to volume, assuming that temperature and amount of gas are constant. As volume increases, pressure decreases. In Dalton’s law of partial pressure, the total pressure exerted by a mixture of gases is equal to the sum of the partial pressure of the gases in mixture.

      According to Henry’s Law for concentration of dissolved gases, at a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid. An equivalent way of stating the law is that the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid.

      Gay-Lussac’s Law states that the pressure of a given mass of gas varies directly with the absolute temperature of the gas, when the volume is kept constant. This law is very similar to Charles’ Law, with the only difference being the type of container. Whereas the container in a Charles’ Law experiment is flexible, it is rigid in a Gay-Lussac’s Law experiment.

    • This question is part of the following fields:

      • Basic Physics
      0
      Seconds
  • Question 7 - A 39-year-old woman, is scheduled for a thyroidectomy for her previously diagnosed Grave's...

    Incorrect

    • A 39-year-old woman, is scheduled for a thyroidectomy for her previously diagnosed Grave's disease. She is eligible for surgery as medical treatment options have failed to control her symptoms and she is the sole guardian for her young children, so radioiodine treatment is unsuitable. While gaining her consent for the surgery, she is told of possible complications of thyroidectomy, which include damage to the sensory branch of the superior laryngeal nerve. What is the name of the sensory nerve that arises from the superior laryngeal nerve?

      Your Answer:

      Correct Answer: Internal laryngeal nerve

      Explanation:

      The superior laryngeal nerve gives off two branches: the sensory branch which is the internal laryngeal nerve, and the motor branch which is the external laryngeal nerve.

      The recurrent laryngeal nerve (RLN) rises from the vagus nerve which supplies the intrinsic muscles of the larynx, except the cricothyroid muscles.

    • This question is part of the following fields:

      • Anatomy
      0
      Seconds
  • Question 8 - A 32-year-old man has multiple stab wounds to his abdomen and is rushed...

    Incorrect

    • A 32-year-old man has multiple stab wounds to his abdomen and is rushed into the emergency. Resuscitative measures are performed, but the patient remains hypotensive. Emergency laparotomy is performed, and it reveals a vessel is bleeding profusely at a certain level of lumbar vertebrae. The vessel is the testicular artery and is ligated. At which lumbar vertebrae is the testicular artery identified?

      Your Answer:

      Correct Answer: L2

      Explanation:

      The important landmarks of vessels arising from the abdominal aorta at different levels of vertebrae are:

      T12 – Coeliac trunk

      L1 – Left renal artery

      L2 – Testicular or ovarian arteries

      L3 – Inferior mesenteric artery

      L4 – Bifurcation of the abdominal aorta.

    • This question is part of the following fields:

      • Anatomy
      0
      Seconds
  • Question 9 - Which of the following is true about number needed to harm? ...

    Incorrect

    • Which of the following is true about number needed to harm?

      Your Answer:

      Correct Answer: The number of patients that must receive a particular treatment for one additional patient to experience an adverse outcome.

      Explanation:

      Number needed to harm are a measure of the impact of a treatment or intervention that is often used to communicate results to patients, clinicians, the public and policymakers. It states how many patients need to be treated for one additional patient to experience an adverse outcome (e.g. a death). It is calculated as the inverse of the absolute risk reduction. It can equally well be applied to harmful outcomes as well as beneficial ones, where it becomes numbers needed to treat (NNT) instead.

      In this way, they are both calculated the same but NNT usually refers to a therapeutic treatment whereas NNH refers to a risk-factor for disease.

    • This question is part of the following fields:

      • Statistical Methods
      0
      Seconds
  • Question 10 - A 49-year-old woman is admitted to hospital. She is scheduled for surgery and...

    Incorrect

    • A 49-year-old woman is admitted to hospital. She is scheduled for surgery and is undergoing preoperative assessment. As part of the preoperative assessment, her functional capacity is estimated. At 50kg in weight, she is able to cycle along a flat surface at a speed of 10-14 miles/hour (8 metabolic equivalents or METs). Provide the best estimated value of oxygen consumption (VO2) for eight METs.

      Your Answer:

      Correct Answer: 1400 mL/minute

      Explanation:

      Oxygen consumption (VO2) refers to the optimal amount of oxygen used by the body during exercise.

      It is calculated mathematically by:

      VO2 = 3.5 x 50 x 8 = 1400 mL/kg/minute

      where,

      1 MET = 3.5 mL O2/kg/minute is utilized by the body.

      Note:

      1 MET Eating
      Dressing
      Use toilet
      Walking slowly on level ground at 2-3 mph
      2 METs Playing a musical instrument
      Walking indoors around house
      Light housework
      4 METs Climbing a flight of stairs
      Walking up hill
      Running a short distance
      Heavy housework, scrubbing floors, moving heavy furniture
      Walking on level ground at 4 mph
      Recreational activity, e.g. golf, bowling, dancing, tennis
      6 METs Leisurely swimming
      Leisurely cycling along the flat (8-10 mph)
      8 METs Cycling along the flat (10-14 mph)
      Basketball game
      10 METs Moderate to hard swimming
      Competitive football
      Fast cycling (14-16 mph).

    • This question is part of the following fields:

      • Clinical Measurement
      0
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  • Question 11 - A previously fit 26-year-old is undergoing surgery to repair an inguinal hernia. He...

    Incorrect

    • A previously fit 26-year-old is undergoing surgery to repair an inguinal hernia. He is breathing on his own, and a supraglottic airway is being maintained via a circle system with air/oxygen and sevoflurane. With a fresh gas flow of 14 L/min, the end-tidal CO2 reading is 8.1 kPa. CO2 pressure is 1.9 kPa. The percentages of oxygen inhaled and exhaled are 38 and 33 percent, respectively. What do you think is the most likely source for these readings?

      Your Answer:

      Correct Answer: Incompetent expiratory valve

      Explanation:

      The patient is rebreathing carbon dioxide that has been exhaled.

      Exhaustion of the soda lime and failure of the expiratory valve are the two most likely causes. A leak in the inspiratory limb is a less likely cause. Increased inhaled and exhaled carbon dioxide levels may appear with a normal-looking capnogram if the expiratory valve is ineffective.

      The patient will exhale into both the inspiratory and expiratory limbs if the inspiratory valve is inoperable. A slanted downstroke inspiratory phase (as the patient inhales carbon dioxide-containing gas from the inspiratory limb) and increased end-tidal carbon dioxide can be seen on the capnogram.

      Even if the soda lime were exhausted, a high fresh gas flow would be enough to prevent rebreathing. The difference in oxygen concentrations in inspired and expired breaths would be less pronounced.

      Hypercapnia is caused by respiratory obstruction and malignant hyperthermia, but not by rebreathing.

    • This question is part of the following fields:

      • Pathophysiology
      0
      Seconds
  • Question 12 - The Fick principle can be used to determine the blood flow to any...

    Incorrect

    • The Fick principle can be used to determine the blood flow to any organ of the body. At rest, which one of these organs has the highest blood flow (ml/min/100g)?

      Your Answer:

      Correct Answer: Thyroid gland

      Explanation:

      After the carotid body, the thyroid gland is the second most richly vascular organ in the body.

      The global blood flow to the thyroid gland can be measured using:
      1. Colour ultrasound sonography
      2. Quantitative perfusion maps using MRI of the thyroid gland using an arterial spin labelling (ASL) method.

      This table shows the blood flow to various organs of the body at rest:
      Organ Blood Flow(ml/minute/100g)
      Hepatoportal 58
      Kidney 420
      Brain 54
      Skin 13
      Skeletal muscle 2.7
      Heart 87
      Carotid body 2000
      Thyroid gland 560

    • This question is part of the following fields:

      • Physiology
      0
      Seconds
  • Question 13 - A breakthrough lipid-lowering therapy for stroke had a number needed to treat (NNT)...

    Incorrect

    • A breakthrough lipid-lowering therapy for stroke had a number needed to treat (NNT) of 20 for the prevention of the primary end-point. These results can be best described as:

      Your Answer:

      Correct Answer: For 1000 patients treated with active therapy, there would be 50 fewer strokes

      Explanation:

      Number needed to treat (NNT) is a time specific epidemiological measure that indicates how many patients would be require for an intervention to prevent one additional bad outcome. A perfect NNT would be 1, where everyone improves with treatment, thus the higher the NNT, the less effective the treatment.

      Thus if you treat 1000 patients then you will expect to have 50 fewer strokes.

    • This question is part of the following fields:

      • Statistical Methods
      0
      Seconds
  • Question 14 - One of two divisions of the autonomic nervous system is the sympathetic nervous...

    Incorrect

    • One of two divisions of the autonomic nervous system is the sympathetic nervous system. It is both anatomically and physiologically different from the parasympathetic nervous system. Which best describes the anatomical layout of the sympathetic nervous system?

      Your Answer:

      Correct Answer: Short myelinated preganglionic neurones from T1-L5 in lateral horns of grey matter of spinal cord, synapse in sympathetic ganglia (neurotransmitter - acetyl choline), long unmyelinated postganglionic neurones, synapse with effector organ (neurotransmitter - adrenaline or noradrenaline)

      Explanation:

      The autonomic nervous system is divided into the sympathetic and parasympathetic nervous system. They are anatomically and physiologically different.

      The sympathetic nervous system arises from the thoracolumbar outflow (T1-L5 ) at the lateral horns of grey matter of the spinal cord. Their preganglionic neurones are usually short myelinated and synapse in ganglia lateral to the vertebral column and have acetyl choline (Ach) as the neurotransmitter. Their postganglionic neurones are longer and unmyelinated and synapse with effector organ where the neurotransmitter is either adrenaline or noradrenaline.

      The outflow of the parasympathetic nervous system is craniosacral. The cranial part originates from the midbrain and medulla (cranial nerves III, VII, IX and X) and the sacral outflow is from S2, S3 and S4. Their preganglionic neurones are usually long myelinated and synapse in ganglia close to the target organ and has Ach as its neurotransmitter. The unmyelinated postganglionic neurones is shorter and they synapse with effector organ. The neurotransmitter here is also Ach.

      Both sympathetic and parasympathetic preganglionic neurons are cholinergic. Only the postganglionic parasympathetic neurons are cholinergic.

    • This question is part of the following fields:

      • Anatomy
      0
      Seconds
  • Question 15 - When the volume of gas is measured, its value should be supported by...

    Incorrect

    • When the volume of gas is measured, its value should be supported by a suitable abbreviation. From the following options, what does the STPD stand for?

      Your Answer:

      Correct Answer: Standard Temperature and Pressure, Dry

      Explanation:

      Gas is composed of large numbers of molecules moving in random directions, separated by distances. They undergo perfectly elastic collisions with each other and the walls of a container and transfer kinetic energy in form of heat. These assumptions bring the characteristics of gases within the range and reasonable approximation to a real gas, particularly how any change in temperature and pressure affect the behaviour of gas. According to different theories and laws proposed, mathematical equations are derived to calculate the volume of gas, also different abbreviations are being used according to given conditions. The abbreviations used are ATP, BTPS, and STPD.
      ATP stands for ambient temperature and barometric pressure, it is used to describe the conditions under which volume of gas is measured.
      BTPS stands for body temperature and pressure saturated with water vapor. These are conditions under which volume of gas exist and all results of lung volume determination should be quoted at BTPS.
      STPD stands for standard temperature and pressure, dry (0C and 760 mm Hg). These are the conditions that are used to describe quantities of individual gases exchanged in the lungs.

    • This question is part of the following fields:

      • Anaesthesia Related Apparatus
      0
      Seconds
  • Question 16 - A 68-year-old man is to be operated.   His past history is significant...

    Incorrect

    • A 68-year-old man is to be operated.   His past history is significant for a stroke, and some residual neurological deficit. The cranial nerves are examined clinically. He is unable to rotate his head to the left side when resistance is applied. Moreover, there is tongue wasting on the right side. There are no unusual sensory signs and symptoms. The most likely reason for these clinical findings is?

      Your Answer:

      Correct Answer: Damage to hypoglossal (XII) and spinal accessory (XI) nerves

      Explanation:

      The upper five cervical segments of the spinal cord give rise to the XI cranial nerve. They connect with a few smaller branches before exiting the skull through the jugular foramen. The sternomastoid and trapezius muscles get their motor supply from the accessory root. Except for the palatoglossus, the hypoglossal nerve supplies motor supply to all tongue muscles.

      The inability to shrug the shoulder on the affected side and rotate the head to the side against resistance is caused by damage to the spinal accessory nerve. This is due to the trapezius and sternomastoid muscles’ weakness.

      The hypoglossal nerve is damaged, resulting in tongue wasting and inability to move from side to side.

      The stylopharyngeus receives motor supply from the glossopharyngeal nerve. It also carries taste sensory fibres from the back third of the tongue, as well as the carotid sinus, carotid body, pharynx, and middle ear.

      Motor supply to the larynx, pharynx, and palate; parasympathetic innervation to the heart, lung, and gut; and sensory fibres from the epiglottis and valleculae are all provided by the vagus nerve.

    • This question is part of the following fields:

      • Pathophysiology
      0
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  • Question 17 - A 40-year old female comes to the GP's office with unexplained weight gain,...

    Incorrect

    • A 40-year old female comes to the GP's office with unexplained weight gain, cold intolerance and fatigue. Her thyroid function tests are performed as there is a suspicion of hypothyroidism. A negative feedback mechanism is incorporated in the control of thyroid hormone release. All of choices below are also controlled by a negative feedback loop except:

      Your Answer:

      Correct Answer: Clotting cascade

      Explanation:

      The correct answer is the clotting cascade, which occurs via a positive feedback mechanism. As clotting factors are attracted to a site, their presence attracts further clotting factors. This continues until a functioning clot is formed.

      This patient has presented with symptoms of hypothyroidism and symptoms include weight gain, lethargy, cold intolerance, dry skin, coarse hair and constipation. It can be treated by replacing the missing thyroid hormone with levothyroxine which is a synthetic version of thyroxine (T4).

      Serum carbon dioxide (CO2) is controlled via a negative feedback mechanism as well. Chemoreceptors can detect when the serum CO2 is high, and send an impulse to the respiratory centre of the brain to increase the respiratory rate. As a result, more CO2 is exhaled which lowers the serum concentration.

      Cortisol is also released according to a negative feedback mechanism. Cortisol acts on both the hypothalamus and the anterior pituitary. Its action serve to decrease the formation of corticotrophin releasing hormone (CRH) and adrenocorticotropic hormone (ACTH), respectively. CRH acts on the anterior pituitary to release ACTH. This then acts on the adrenal gland to cause the release of cortisol. Thus, inhibition of CRH and ACTH formation results in high levels of cortisol which inhibit its further release.

      Blood pressure (BP) is controlled via a negative feedback mechanism. Low BP results in renin-angiotensin-aldosterone system (RAAS) activation. This leads to vasoconstriction and retention of salt and water which increased BP.
      Blood sugar is controlled via a negative feedback mechanism. A rise in blood sugar causes insulin to be released. Insulin acts to transport glucose into the cell which lowers blood sugar.

    • This question is part of the following fields:

      • Physiology And Biochemistry
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  • Question 18 - Drug toxicity when using bupivacaine is most likely to occur when this local...

    Incorrect

    • Drug toxicity when using bupivacaine is most likely to occur when this local anaesthetic technique is performed.

      Your Answer:

      Correct Answer: Intercostal nerve block

      Explanation:

      An intercostal nerve block is used for therapeutic and diagnostic purposes. Intercostal nerve blocks manage acute and chronic pain in the chest area. Common indications are chest wall surgery and shingles or postherpetic neuralgia.

      An intercostal nerve block is also an effective option for the management of pain associated with chest trauma and rib fractures. These blocks have been shown to improve oxygenation and respiratory mechanics, and offer pain relief that is comparable to that of epidural analgesia.

      This technique, however, is limited by the relatively large doses of local anaesthetic required, and relatively high intravascular uptake from the intercostal space, increasing risk of local anaesthetic toxicity.

    • This question is part of the following fields:

      • Pharmacology
      0
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  • Question 19 - You performed pelvic ultrasound of Mrs Aciman as she had pelvic bloating and...

    Incorrect

    • 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:

      Correct 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
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  • Question 20 - A survey aimed at finding out mean glucose level in individuals that took...

    Incorrect

    • A survey aimed at finding out mean glucose level in individuals that took antipsychotics medicines was conducted. The results were as follows: Mean Value: 7mmol/L, Standard Deviation: 6mmol/L, Sample Size: 9, Standard Error: 2mmol/L. For a confidence interval of 95%, which of the option presents the correct range up to the nearest value?

      Your Answer:

      Correct Answer: 3-11 mmol/L

      Explanation:

      Key Point: While finding out confidence intervals, standard errors are used. Standard error and Standard deviation are two distinct entities and should not be confused.

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

      Multiply the standard error by 3.

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

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

      The range turns out to be 1-13 mmol/L.

      For a confidence interval of 68%, multiply the standard error with 1 and repeat the process. The range found for this interval is 3-11 mmol/L.

      For a 95% confidence interval. Standard Error is multiplied by 1.96 which gives us the limit ranging from 3.08 to 10.92 mmol/L which could be approximated to 3-11 mmol/L.

    • This question is part of the following fields:

      • Statistical Methods
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  • Question 21 - Heights of 100 individuals(adults) who were administered steroids at any stage during childhood...

    Incorrect

    • Heights of 100 individuals(adults) who were administered steroids at any stage during childhood was studied. The mean height was found to be 169cm with the data having a standard deviation of 16cm. What will be the standard error associated with the mean?

      Your Answer:

      Correct Answer: 1.6

      Explanation:

      Standard error can be calculated by the following formula:
      Standard Error= (Standard Deviation)/ˆš(Sample Size)
      = (16) / ˆš(100)
      = 16 / 10
      = 1.6

    • This question is part of the following fields:

      • Statistical Methods
      0
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  • Question 22 - Which of the following statements about intra-arterial blood pressure monitoring is true? ...

    Incorrect

    • Which of the following statements about intra-arterial blood pressure monitoring is true?

      Your Answer:

      Correct Answer: Fluid-filled tubing conducts the intravascular pressure wave from the catheter tip to the transducer

      Explanation:

      Intra-arterial blood pressure monitoring is a common place procedure in the ICU. It is used to provide accurate beat-to-beat information using a pressure wave displayed on a monitor.

      It involves catheter insertion in a peripheral artery (most commonly the radial, brachial and dorsalis pedis arteries). Each subsequent contraction of cardiac muscles results in pressure wave which induces a mechanical motion of flow in the catheter. This mechanical motion is then passed on to a transducer through a rigid fluid-filled tubing. The transducer is the able to process this mechanical motion into electrical signals which are displayed as arterial waves and pressure represented numerically on the monitor.

      The transducer should be placed at the same level as the heart on the phlebostatic axis, and at the level of the atria (the 4th intercostal space, in the mid-axillary line).

      Air bubbles and catheter tubing with longer lengths result in wave dampening (rounding of the resulting pressure waves). This dampening causes a decrease in systolic pressure, and an increase in diastolic pressure.

    • This question is part of the following fields:

      • Clinical Measurement
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  • Question 23 - The following statement is true with regards to the Nernst equation: ...

    Incorrect

    • The following statement is true with regards to the Nernst equation:

      Your Answer:

      Correct Answer: It is used to calculate the potential difference across a membrane when the individual ions are in equilibrium

      Explanation:

      The Nernst equation is used to calculate the membrane potential at which the ions are in equilibrium across the cell membrane.

      The normal resting membrane potential is -70 mV (not + 70 mV).

      The equation is:
      E = RT/FZ ln {[X]o
      /[X]i}

      Where:
      E is the equilibrium potential
      R is the universal gas constant
      T is the absolute temperature
      F is the Faraday constant
      Z is the valency of the ion
      [X]o is the extracellular concentration of ion X
      [X]i is the intracellular concentration of ion X.

    • This question is part of the following fields:

      • Physiology
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  • Question 24 - Regarding bilirubin, which one of the following statement is true? ...

    Incorrect

    • Regarding bilirubin, which one of the following statement is true?

      Your Answer:

      Correct Answer: Conjugated bilirubin is stored in the gall bladder

      Explanation:

      Bilirubin is the tetrapyrrole and a catabolic product of heme. 70-90% of bilirubin is end product of haemoglobin degradation in the liver.

      Bilirubin circulates in the blood in 2 forms; unconjugated and conjugated bilirubin.

      Unconjugated bilirubin is insoluble in water. It travels through the bloodstream to the liver, where it changes from insoluble into a soluble form (i.e.; unconjugated into conjugated form).

      This conjugated bilirubin travels from the liver into the small intestine and the gut bacteria convert bilirubin into urobilinogen and then into urobilin (not urobilin to urobilinogen). A very small amount passes into the kidneys and is excreted in urine.

    • This question is part of the following fields:

      • Physiology
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  • Question 25 - A 45-year old male who was involved in a road traffic accident has...

    Incorrect

    • A 45-year old male who was involved in a road traffic accident has had to receive a large blood transfusion of whole blood which is two weeks old. Which of these best describes the oxygen carrying capacity of this blood?

      Your Answer:

      Correct Answer: It will have an increased affinity for oxygen

      Explanation:

      With respect to oxygen transport in cells, almost all oxygen is transported within erythrocytes. There is limited solubility and only 1% is carried as solution. Thus, the amount of oxygen transported depends upon haemoglobin concentration and its degree of saturation.

      Haemoglobin is a globular protein composed of 4 subunits. Haem is made up of a protoporphyrin ring surrounding an iron atom in its ferrous state. The iron can form two additional bonds – one is with oxygen and the other with a polypeptide chain.
      There are two alpha and two beta subunits to this polypeptide chain in an adult and together these form globin. Globin cannot bind oxygen but can bind to CO2 and hydrogen ions.
      The beta chains are able to bind to 2,3 diphosphoglycerate. The oxygenation of haemoglobin is a reversible reaction. The molecular shape of haemoglobin is such that binding of one oxygen molecule facilitates the binding of subsequent molecules.

      The oxygen dissociation curve (ODC) describes the relationship between the percentage of saturated haemoglobin and partial pressure of oxygen in the blood.
      Of note, it is not affected by haemoglobin concentration.

      Chronic anaemia causes 2, 3 DPG levels to increase, hence shifting the curve to the right

      Haldane effect – Causes the ODC to shift to the left. For a given oxygen tension there is increased saturation of Hb with oxygen i.e. Decreased oxygen delivery to tissues.
      This can be caused by:
      -HbF, methaemoglobin, carboxyhaemoglobin
      -low [H+] (alkali)
      -low pCO2
      -ow 2,3-DPG
      -ow temperature

      Bohr effect – causes the ODC to shifts to the right = for given oxygen tension there is reduced saturation of Hb with oxygen i.e. Enhanced oxygen delivery to tissues. This can be caused by:
      – raised [H+] (acidic)
      – raised pCO2
      -raised 2,3-DPG
      -raised temperature

    • This question is part of the following fields:

      • Physiology And Biochemistry
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  • Question 26 - In a diagnosis of a compensated respiratory acidosis, which of the following arterial...

    Incorrect

    • In a diagnosis of a compensated respiratory acidosis, which of the following arterial blood gas results is likely to be seen?

      Your Answer:

      Correct Answer: pH = 7.34
      PaCO2 = 7.2 kPa
      HCO3 = 29

      Explanation:

      During normal tissue metabolism, there is production of CO2 (acid) which is then expired by the lungs. If metabolism switches from aerobic to anaerobic due to a lack of oxygen, the tissues are unable to completely oxidise sugars to CO2. As a consequence, the sugars can only be partially oxidised to lactic acid. Since lactic acid cannot be expired by the lungs, it remains in the circulation leading to metabolic acidosis.

      Also, normal tissue metabolism leads to the production of some amount of acid from the breakdown of proteins. These acids are excreted from the body by kidney filtration. Renal failure will therefore results in acidosis after several days.

      An increased acidosis stimulates the brain’s respiratory centres to increase the respiratory rate. This lowers the CO2 in the blood, leading to a decrease in its acidity. Renal excretion removes the excess acid, resulting in a normal pH, and a reduced PaCO2 and HCO3.

      pH PaCO2 (kPa) HCO3
      Compensated respiratory acidosis 7.34 7.2 29
      Acute respiratory acidosis 7.25 7.3 22
      Compensated metabolic acidosis 7.34 3.6 14
      Metabolic acidosis 7.21 5.3 15
      Metabolic alkalosis 7.51 5.1 30

    • This question is part of the following fields:

      • Pathophysiology
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  • Question 27 - Conclusive evidence suggests that rate for the prevalence of schizophrenia in United Kingdom...

    Incorrect

    • Conclusive evidence suggests that rate for the prevalence of schizophrenia in United Kingdom is around 1%. Which term can be used to describe that?

      Your Answer:

      Correct Answer: Endemic

      Explanation:

      An epidemic is declared when the increase in a give disease is above a certain level in a specific interval of time.

      An endemic is the general, usual level of a disease in a population at a particular time.

      A pandemic is an epidemic that is spread across many countries and continents.

    • This question is part of the following fields:

      • Statistical Methods
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  • Question 28 - A 68-year-old woman is a known case of acute myeloid leukaemia and was...

    Incorrect

    • A 68-year-old woman is a known case of acute myeloid leukaemia and was treated with chemotherapy as a child. She now presents in rhesus, and you are called in to attend this patient as it is getting difficult to gain vascular access in her arms. The medical registrar asks you to site a cannula during the arrest call as intraosseous access is delayed. The ITU SHO wants to assist you in performing a venous cutdown of one of the veins in her ankle that passes anterior to the medial malleolus. Which vessel is this?

      Your Answer:

      Correct Answer: Long saphenous vein

      Explanation:

      Venous cutdown is a surgical procedure when venous access is difficult, and other procedures like the Seldinger technique, ultrasound-guided venous access, and intraosseous vascular access have failed.

      The vein of choice for venous cutdown is the long/great saphenous vein. It is part of the superficial venous collecting system of the lower extremity. It is the preferred vein as the long saphenous vein has anatomic consistency and is superficially located at the ankle anterior to the medial malleolus. It is also the most commonly used conduit for cardiovascular bypass operations.

      Origin- in the foot at the confluence of the dorsal vein of the first digit and the dorsal venous arch of the foot
      Route- runs ANTERIOR to the medial malleolus and travels up in the medial leg and upper thigh.
      Termination: in the femoral vein within the femoral triangle

      Regarding the other options:
      The short saphenous vein passes posterior to the lateral malleolus.
      The dorsalis pedis vein accompanies the dorsalis pedis artery on the anterior foot.
      The posterior tibial vein is part of the deep venous system accompanying the posterior tibial artery. There is no significant sural vein (there is a sural nerve), but the sural veins accompany the sural arteries and drain to the popliteal vein.

    • This question is part of the following fields:

      • Anatomy
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  • Question 29 - The child-Pugh scoring system can be used, if risk classifying a patient with...

    Incorrect

    • 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:

      Correct 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
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  • Question 30 - With regards to arterial oxygen content, which of the following contributes most from...

    Incorrect

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

      Your Answer:

      Correct 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
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