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Question 1
Correct
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A 28-year-old patient who has been in a car accident needs to be intubated using a rapid sequence induction. As an induction agent, you intend to use etomidate.
Etomidate works by interacting with which type of receptor?Your Answer: Gamma-aminobutyric acid (GABA)
Explanation:Etomidate is a carboxylated imidazole derivative with a short half-life that is primarily used to induce anaesthesia.
It is thought to modulate fast inhibitory synaptic transmission in the central nervous system by acting on GABA type A receptors.
The dose for anaesthesia induction is 0.3 mg/kg. Etomidate takes 10-65 seconds to take effect after an intravenous injection, and it lasts 6-8 minutes. With repeated administration, the effects are non-cumulative.The relative cardiovascular stability of etomidate is noteworthy. During induction, it causes less hypotension than thiopental sodium and propofol. It’s also linked to a quick recovery without the hangover.
Etomidate is a strong steroidogenesis inhibitor. The drug inhibits the enzymes responsible for adrenal 11 beta-hydroxylase and cholesterol cleavage, resulting in a decrease in cortisol and aldosterone synthesis for up to 24 hours after administration. It should not be used to maintain anaesthesia because of the adrenocortical suppression.
Other side effects associated with etomidate use include:
Vomiting and nausea
The injection causes pain (in up to 50 percent )
Phlebitis and thrombosis of the veins
Heart block and arrhythmias
Hyperventilation
Apnoea and respiratory depression
It has the potential to cause both hypo- and hypertension.
Critically ill patients have a higher mortality rate. -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 2
Incorrect
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Atracurium is used as a muscle relaxant during endotracheal intubation. This drug’s mechanism of action is best described by which of the following?
Your Answer: Muscarinic acetylcholine receptor antagonist
Correct Answer: Nicotinic acetylcholine receptor antagonist
Explanation:Atracurium is a non-depolarizing neuromuscular blocker that is used to help with intubation and controlled ventilation by causing muscle relaxation and paralysis.
At the neuromuscular junction’s post-synaptic membrane, atracurium competes with acetylcholine for nicotinic (N2) receptor binding sites. This prevents the receptors from being stimulated by acetylcholine.
Muscle paralysis occurs gradually due to the competitive blockade.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 3
Correct
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Regarding benzodiazepines, which of the following statements is INCORRECT:
Your Answer: Diazepam is a short-acting benzodiazepine.
Explanation:Diazepam is used to produce mild sedation with amnesia. It is a long-acting drug with active metabolites and a second period of drowsiness can occur several hours after its administration. Midazolam is a water-soluble benzodiazepine that is often used in preference to intravenous diazepam; recovery is faster than from diazepam, but may be significantly longer in the elderly, in patients with a low cardiac output, or after repeated dosing. Midazolam is associated with profound sedation when high doses are given intravenously or when it is used with certain other drugs.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 4
Incorrect
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Which of the following local anaesthetics has the longest duration of action:
Your Answer: Prilocaine
Correct Answer: Bupivacaine
Explanation:Bupivacaine has a longer duration of action than the other local anaesthetics, up to 8 hours when used for nerve blocks. It has a slow onset, taking up to 30 minutes for full effect. It is often used in lumbar epidural blockade and is particularly suitable for continuous epidural analgesia in labour, or for postoperative pain relief. It is the principal drug used for spinal anaesthesia.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 5
Incorrect
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Which of the following is NOT a typical side effect of thiopental sodium:
Your Answer: Cough and laryngospasm
Correct Answer: Seizures
Explanation:Extravasation of thiopental during injection can lead to tissue damage. Accidental intra-arterial injection causes vasospasm and may lead to thrombosis and tissue necrosis. Other side effects include involuntary muscle movements on induction, cough and laryngospasm, arrhythmias, hypotension, headache and hypersensitivity reactions. Thiopental sodium has anticonvulsant properties and does not cause seizures.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 6
Incorrect
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Regarding propofol, which of the following statements is INCORRECT:
Your Answer: Propofol decreases the ventilatory response to carbon dioxide.
Correct Answer: A lower induction dose of propofol is required in children.
Explanation:Elderly patients have a reduced volume of distribution and slower clearance of the drug. They are therefore more sensitive to the effects of propofol and the drug wears off more slowly. They need less of the drug, which should be injected slowly, monitoring its effect on the patient. The opposite is true in children, who need larger doses of propofol. This is particularly so in children under three years of age. Propofol is not recommended for induction of anaesthesia in children under one month of age or for maintenance of anaesthesia in children under three years old.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 7
Incorrect
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Which of the following is NOT a contraindication to the use of diazepam:
Your Answer: Unstable myasthenia gravis
Correct Answer: Acute alcohol withdrawal
Explanation:Benzodiazepines are used to treat symptoms in patients with acute alcohol withdrawal syndrome.
Benzodiazepines are contraindicated in:
Respiratory depression
Marked neuromuscular respiratory weakness, such as unstable myasthenia gravis
Obstructive sleep apnoea syndrome (symptoms may be aggravated)
Severe hepatic impairment (the elimination half-life of diazepam may be prolonged; increased risk of coma)
Phobic or obsessional states, chronic psychosis or hyperkinesis (paradoxical reactions may occur). -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 8
Incorrect
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A 25-year-old patient requires procedural sedation for reduction of an open fracture of his tibia and fibula. You plan on using ketamine as the sedative agent.
Ketamine works as a result of action on what type of receptor? Select ONE answer only.Your Answer: Dopamine
Correct Answer: N-methyl-D-aspartate (NMDA)
Explanation:Ketamine is the only anaesthetic agent available that has analgesic, hypnotic, and amnesic properties. When used correctly it is a very useful and versatile drug.
Ketamine acts by non-competitive antagonism of the NMDA receptor Ca2+ channel pore and also inhibits NMDA receptor activity by interaction with the phencyclidine binding site.
Ketamine can be used intravenously and intramuscularly. The intramuscular dose is 10 mg/kg, and when used by this route, it acts within 2-8 minutes and has a duration of action of 10-20 minutes. The intravenous dose is 1.5-2 mg/kg administered over a period of 60 seconds. When used intravenously, it acts within 30 seconds and has a duration of action of 5-10 minutes. Ketamine is also effective when administered orally, rectally, and nasally.
Ketamine causes tachycardia, an increase in blood pressure, central venous pressure, and cardiac output, secondary to an increase in sympathetic tone. Baroreceptor function is well maintained, and arrhythmias are uncommon.
The main disadvantage to the use of ketamine is the high incidence of hallucinations, nightmares, and other transient psychotic effects. These can be reduced by the co-administration of a benzodiazepine, such as diazepam or midazolam.
The main side effects of ketamine are:
Nausea and vomiting
Hypertension
Nystagmus
Diplopia
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 9
Correct
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You plan to use plain 1% lidocaine for a ring block on a finger that needs suturing.
Which SINGLE statement regarding the use of 1% lidocaine, in this case, is true?Your Answer: Lidocaine works by blocking fast voltage-gated sodium channels
Explanation:Lidocaine is a tertiary amine that is primarily used as a local anaesthetic but can also be used intravenously in the treatment of ventricular dysrhythmias.
Lidocaine works as a local anaesthetic by diffusing in its uncharged base form through neural sheaths and the axonal membrane to the internal surface of the cell membrane sodium channels. Here it alters signal conduction by blocking the fast voltage-gated sodium channels. With sufficient blockage, the membrane of the postsynaptic neuron will not depolarise and will be unable to transmit an action potential, thereby preventing the transmission of pain signals.
Each 1 ml of plain 1% lidocaine solution contains 10 mg of lidocaine hydrochloride. The maximum safe dose of plain lidocaine is 3 mg/kg. When administered with adrenaline 1:200,000, the maximum safe dose is 7 mg/kg. Because of the risk of vasoconstriction and tissue necrosis, lidocaine should not be used in combination with adrenaline in extremities such as fingers, toes, and the nose.
The half-life of lidocaine is 1.5-2 hours. Its onset of action is rapid within a few minutes, and it has a duration of action of 30-60 minutes when used alone. Its duration of action is prolonged by co-administration with adrenaline (about 90 minutes).
Lidocaine tends to cause vasodilatation when used locally. This is believed to be due mainly to the inhibition of action potentials via sodium channel blocking in vasoconstrictor sympathetic nerves. -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 10
Correct
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Which of the following is NOT a typical feature of benzodiazepine toxicity:
Your Answer: Hyperventilation
Explanation:Features of benzodiazepine toxicity include: drowsiness, ataxia, dysarthria, nystagmus, occasionally respiratory depression and coma
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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SESSION STATS - PERFORMANCE PER SPECIALTY
