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  • Question 1 - With a 10-day history of severe vomiting, a 71-year-old man with a gastric...

    Incorrect

    • With a 10-day history of severe vomiting, a 71-year-old man with a gastric outlet obstruction is admitted to the surgical ward.

      The serum biochemical results listed below are available:

      Sodium 128 mmol/L (137-144)
      Potassium 2.6 mmol/L (3.5-4.9)
      Chloride 50 mmol/L (95-107)
      Urea 12 mmol/L (2.5-7.5)
      Creatinine 180 µmol/L (60-110)

      Which of the following do you think you are most likely to encounter?

      Your Answer: Bicarbonate 45-50 mmol/L

      Correct Answer: The standard base excess will be higher than actual base excess

      Explanation:

      Hydrochloric acid is lost when you vomit for a long time (HCl). As a result, the following can be expected, in varying degrees of severity:

      Hypokalaemia
      Hypochloraemia
      Increased bicarbonate to compensate for chloride loss and metabolic alkalosis

      The alkalosis causes potassium to move from the intracellular to the extracellular compartment at first. Long-term vomiting and dehydration cause potassium to be excreted by the kidneys in order to conserve sodium. Dehydration can cause urea and creatinine levels to rise.

      The actual base excess is always greater than the standard base excess.

      The actual base excess (BE) is a measurement of a base’s contribution to a blood gas picture’s metabolic component. It’s the amount of base that needs to be added to a blood sample to bring the pH back to 7.4 after the respiratory component of a blood gas picture has been corrected (PaCO2 of 40 mmHg or 5.3 kPa). The BE has a normal range of +2 to 2. A large positive BE indicates a severe metabolic alkalosis, while a large negative BE indicates a severe metabolic acidosis. As a result, the actual BE in vitro is unaffected by CO2.

      In vivo, however, standard BE is not independent of pCO2 because blood with haemoglobin acts as a better buffer than total ECF.

      As a result, it is impossible to tell the difference between compensating for a respiratory disorder and compensating for the presence of a primary metabolic disorder.

      The differences between in vitro and in vivo behaviour can be mostly eliminated if the BE is calculated for a haemoglobin concentration of 50 g/L (the ‘effective’ or virtual value of Hb if it was distributed throughout the extracellular space) rather than the actual haemoglobin. Because haemoglobin has a lower buffering capacity, the standard BE is higher than the actual BE. It reflects the BE better in the extracellular space rather than just the intravascular compartment.

    • This question is part of the following fields:

      • Pathophysiology
      41.3
      Seconds
  • Question 2 - A 72-year-old woman with a medical history of ischaemic heart disease, hypertension, and...

    Correct

    • A 72-year-old woman with a medical history of ischaemic heart disease, hypertension, and hypothyroidism was brought to ER with a change in her mental state over the past few hours. Medications used by her were hydrochlorothiazide, aspirin, ramipril, and levothyroxine.

      On physical examination, decreased skin turgor, orthostatic hypotension, and disorientation of time and place were found. There were no significant neurological signs.

      Initial biochemical tests are as follows:

      Na: 111 mmol/L (135-145)
      K: 4.1 mmol/L (3.5-5.1)
      Cl: 105 mmol/L (99-101)
      Bic: 29 mmol/L (22-29)
      Urea: 16.4 mmol/L (1.7-8.3)
      Creatinine: 320µmol/L (44-80)
      Glucose: 13.5mmol/L (3.5-5.5)
      Plasma osmolality: 278mOsm/kg
      Urinary osmolality: 450mOsm/kg
      TSH: 6.2 miu/L (0.1-6.0)
      Free T4: 10.1 pmol/L (10-25)
      Free T3: 1.4nm/L (1.0-2.5)

      Which of the following is most likely cause for this condition of the patient?

      Your Answer: Drug idiosyncrasy

      Explanation:

      Based on the laboratory reports, the patient is suffering from significant hyponatremia. The symptoms of hyponatremia are mainly neurological and depend on the severity and rapidity of onset of hyponatremia.

      Patient symptom according to the hyponatremia level is correlated below:

      125 – 130mmol/L – Nausea and malaise
      115 – 125mmol/L – Headache, lethargy, seizures, and coma
      <120mmol/L - Up to 11% present with coma.

    • This question is part of the following fields:

      • Pathophysiology
      53.4
      Seconds
  • Question 3 - A patient is evaluated for persistent dysphonia six months after undergoing a subtotal...

    Correct

    • A patient is evaluated for persistent dysphonia six months after undergoing a subtotal thyroidectomy.

      Which of the following is the most likely reason for the change in this patient's voice?

      Your Answer: Damage to recurrent laryngeal nerve

      Explanation:

      After thyroid surgery, about 10-15% of patients experience a temporary subjective voice change of varying degrees. A frog in the throat or cracking of the voice, or a weak voice, are common descriptions. These modifications are only temporary, lasting a few days to a few weeks.

      Swelling of the muscles in the area of the dissection, as well as inflammation and oedema of the larynx due to the dissection, or minor trauma from the tracheal tube, are all suspected causes.

      On both sides of the thyroid gland, the superior laryngeal nerve (EBSLN) runs along the upper part. The muscles that fine-tune the vocal cords are innervated by these nerves. The quality of their voice is usually normal if they are injured, but making high-pitched sounds may be difficult. Injury to the EBSLN occurs in about 2% of the population.

      Injuries to the recurrent laryngeal nerve (RLN) have been reported to occur in 1 percent to 14 percent of people. Except for the cricothyroid muscle, the RLN supplies all of the laryngeal intrinsic muscles.

      This complication is usually unilateral and temporary, but it can also be bilateral and permanent, and it can be intentional or unintentional. The most common complication following thyroid surgery is a permanent lesion of damaged RLN, which manifests as an irreversible phonation dysfunction.

      The crico-arytenoid joint dislocation is a relatively uncommon complication of tracheal intubation and blunt neck trauma. The probability is less than one in a thousand.

      Vocal cord polyps affect 0.8 percent of people.

    • This question is part of the following fields:

      • Pathophysiology
      17.7
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  • Question 4 - With a cervical dilation of 9 cm, a 23-year-old term primigravida is in...

    Incorrect

    • With a cervical dilation of 9 cm, a 23-year-old term primigravida is in labour. She is otherwise in good health. She's been in labour for 14 hours and counting.

      Early foetal pulse decelerations can be seen on the cardiotocograph, and a recent foetal scalp blood sample revealed a pH of 7.25.

      Which of the following is true about this patient's care and management?

      Your Answer: The patient requires a category 2 caesarean section under general anaesthetic

      Correct Answer: Monitor for downward trend in fetal scalp blood pH as caesarean section is not indicated at the present time

      Explanation:

      Once the decision to deliver a baby by caesarean section has been made, it should be carried out with a level of urgency commensurate with the risk to the baby and the mother’s safety.

      There are four types of caesarean section urgency:

      Category 1 – Endangering the life of the mother or the foetus
      Category 2 – Maternal or foetal compromise that is not immediately life threatening
      Category 3 – Early delivery is required, but there is no risk to the mother or the foetus.
      Category 4: Elective delivery at a time that is convenient for both the mother and the maternity staff.

      Caesarean sections for categories 1 and 2 should be performed as soon as possible after the decision is made, especially for category 1. For category 1 caesarean sections, a decision to deliver time of 30 minutes is currently used.

      In most cases, Category 2 caesarean sections should be performed within 75 minutes of making the decision.

      The condition of the woman and the unborn baby should be considered when making a decision for a quick delivery, as it may be harmful in some cases.

      There is no evidence of foetal compromise in the example above (early foetal pulse decelerations and a pH of less than 7.25). Early foetal pulse decelerations are most likely caused by the uterus compressing the foetal head. The foetus is not harmed by these. A spinal anaesthetic is preferred over a general anaesthetic whenever possible.

      If the foetal scalp blood pH is greater than 7.25, it’s a good idea to repeat the test later and look for any changes. When a foetus decelerates, the mother should be given oxygen, kept in a left lateral position, and kept hydrated to avoid the need for a caesarean section.

    • This question is part of the following fields:

      • Pathophysiology
      85.3
      Seconds
  • Question 5 - If a patient is to be placed under general anaesthesia using total intravenous...

    Correct

    • If a patient is to be placed under general anaesthesia using total intravenous technique with target-controlled infusions of propofol and remifentanil, what safety precaution is the most vital in this a scenario?

      Your Answer: Cannula access site clearly visible and regularly checked

      Explanation:

      According to the Safe Anaesthesia Liaison Group, the most important factor to consider the cannula access, and if the patient is properly receiving the total intravenous anaesthesia. The cannula access must be regularly checked for kinks, leaks and disconnections.

      Below are the safety precautions and policies to be followed for total intravenous anaesthesia among children and adults:

      When administering TIVA, a non-return valve must be used on any intravenous fluid line;
      When using equipment, it is essential that clinical staff know its limitations and uses;
      Sites of intravenous infusions should be visible so they may be monitored for disconnection, leaks or perivenous infusion into the subcutaneous tissues; and,
      Organisations must give preference to clearly labelled intravenous connectors and valves.

    • This question is part of the following fields:

      • Pathophysiology
      24.7
      Seconds
  • Question 6 - A 52-year old man was placed under general anaesthesia for an emergent open...

    Incorrect

    • A 52-year old man was placed under general anaesthesia for an emergent open cholecystectomy. As part of the induction, suxamethonium was administered at 1.5mg/kg. Post-operatively, there was failure to restore muscle twitch responses over a course of five hours.

      Clinical chemistry studies were obtained and showed the following results:
      Butrylcholinesterase (BChE) activity: 49 U/L (Reference range: 3300-10,300 U/L)
      Dibucaine number: <4% (Reference range: 83-88%)

      The attending physician gave an initial diagnosis of Suxamethonium Apnoea.

      What is the most probable phenotype of BChE of the patient?

      Your Answer: AS (atypical/silent)

      Correct Answer: S (silent)

      Explanation:

      Silent (S) is the most probable phenotype of the patient. In S phenotype, patients have significantly reduced levels of BChE, the lowest among the four phenotypes. Because of this, individuals with S phenotype are subjected to long periods of apnoea. In addition, their dibucaine number is very low.

      Other BChE phenotypes are the following:

      Usual (U)
      Atypical (A)
      Fluoride-resistant (F)

    • This question is part of the following fields:

      • Pathophysiology
      32.9
      Seconds
  • Question 7 - A 68-year old female is brought to the Emergency Room for abdominal pain....

    Incorrect

    • A 68-year old female is brought to the Emergency Room for abdominal pain. Medical history revealed that she is on long-term warfarin therapy for deep vein thrombosis.

      Upon further investigation, the patient is hypotensive at 80/60 mmHg, and an abdominal mass is palpable on the umbilical area. An initial diagnosis of ruptured abdominal aortic aneurysm (AAA) is made. Moreover, blood tests show an international normalised ratio (INR) of 4.2.

      Which of the following products should be initially transfused or administered to the patient to reverse the anticoagulation?

      Your Answer: Intravenous vitamin K

      Correct Answer: Prothrombin complex

      Explanation:

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

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

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

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

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

    • This question is part of the following fields:

      • Pathophysiology
      18.2
      Seconds
  • Question 8 - A 70-year-old man presents to hospital complaining of dysphagia. He is scheduled for...

    Correct

    • A 70-year-old man presents to hospital complaining of dysphagia. He is scheduled for a rigid oesophagoscopy.

      On examination, He is noted to have severe osteoarthritis in his cervical spine resulting in limited rotation and flexion-extension. He has no other neurological signs or symptoms.

      He is given anaesthesia for the procedure, which is complicated by a difficult intubation (Cormack-Lehane 3), but was eventually achieved using a gum elastic bougie.

      After recovering from anaesthesia, he is examined and found to have severe motor weakness of upper limbs, and mild motor weakness of lower limbs, bladder dysfunction and sensory loss of varying degrees below the level of C5.

      What incomplete spinal cord lesion is most likely to be responsible for his symptoms?

      Your Answer: Central cord syndrome

      Explanation:

      Central cord syndrome is the most commonly occurring type of partial spinal cord lesion. It is more likely to occur in older patients with cervical spondylosis and a hyperextension injury. The injury to the spinal cord occurs in the grey matter causing the following symptoms:

      Disproportionally higher motor function weakness in the upper limbs than in lower limbs
      Dysfunction of the bladder
      Degrees of sensory loss below the level of the lesion

      An anterior spinal artery infarction will interrupt the corticospinal tract resulting in paralysis of motor function, loss of pain and temperature sensation, all occurring below the level of the injury.

      Brown-Sequard syndrome occurs as a result of the hemisection of the spinal cord. Its symptoms include ipsilateral upper motor neurone paralysis and loss of proprioception, with contralateral loss of pain and temperature sensation.

      Spinal cord infarctions rarely occur in the posterior spinal artery.

      Cauda equina syndrome occurs as a result of compression of the lumbosacral spinal nerve roots below the level of the conus medullaris. Injury to these nerves will cause partial or complete loss of movement and sensation in this distribution.

    • This question is part of the following fields:

      • Pathophysiology
      50.3
      Seconds
  • Question 9 - The parameter that is indirectly measured from a blood gas analysis is? ...

    Correct

    • The parameter that is indirectly measured from a blood gas analysis is?

      Your Answer: Standard bicarbonate

      Explanation:

      Automated blood gas analysers are commonly used to analyse blood gas samples, and they measure specific components of the arterial blood gas sample, whether directly or indirectly.

      The following are the components of arterial blood gas:

      pH = measured (directly determined) acid-base balance of the blood

      PaO2 = measured partial pressure of oxygen in arterial blood

      PaCO2 = measured partial pressure of carbon dioxide in arterial blood

      HCO3 = calculated (indirectly determined) concentration of bicarbonate in arterial blood

      Base excess/deficit = calculated relative excess or deficit of base in arterial blood

      SaO2 = calculated arterial oxygen saturation unless a co-oximetry is obtained, in which case it is measured

    • This question is part of the following fields:

      • Pathophysiology
      14
      Seconds
  • Question 10 - In the Advanced Life Support algorithm, intravenous epinephrine 1mg every three to five...

    Incorrect

    • In the Advanced Life Support algorithm, intravenous epinephrine 1mg every three to five minutes is indicated during in-hospital cardiac arrest due to ventricular fibrillation (VF) following three DC shocks.

      Which of the following indicates the most important reason for using epinephrine?

      Your Answer: Positive inotrope effect

      Correct Answer: Preferential distribution of blood to the coronary and cerebral circulation

      Explanation:

      Epinephrine is used for the treatment of cardiac arrest because it causes vasoconstriction via the alpha-adrenergic (?1) receptor. This vasoconstriction increases cerebral and coronary blood flow by increasing mean arterial, aortic diastolic, and cerebral pressures. Furthermore, epinephrine is also a?1 and ?2 adrenoreceptor agonist which shows inotrope, chronotrope, and bronchodilator effects.
      – Adrenaline is also used to prolong the duration of action and decrease the systemic toxicity of local anaesthetics.
      – Preferred route of adrenaline in patients with cardiac arrest is i.v. followed by intra-osseous and endotracheal

    • This question is part of the following fields:

      • Pathophysiology
      25.7
      Seconds

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