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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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Approximately how long is the duration of a lidocaine block (when given with adrenaline):
Your Answer: 30 minutes
Correct Answer: 90 minutes
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 3
Correct
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A 34-year-old male is brought into the Emergency Department by the paramedics after a road traffic accident. After a quick triage, you establish that he will need to be intubated, and you ask for some ketamine to be prepared.
Which one of the following options regarding this drug is true?Your Answer: It is the only anaesthetic agent available that has analgesic, hypnotic, and amnesic properties
Explanation:Ketamine is a dissociative anaesthetic with analgesic, amnesic, and hypnotic effects. It is the only anaesthetic agent which causes all three of these effects.
Ketamine exerts its action by non-competitive antagonism at the NMDA (N-methyl-D-aspartate) receptor. Due to its analgesic property, Ketamine is given so that patients do not retain memories of short term procedures. Ketamine is used for the induction and maintenance of anaesthesia in general surgery and for treating burn wounds, battlefield injuries, and children who cannot tolerate other anaesthetic or analgesic agents.
It can be given by both intravenous and intramuscular routes. Ketamine causes cardiac stimulation by increasing the sympathetic tone. The major side effect is increased intracranial pressure as an increase in the sympathetic tone causes vasoconstriction and an increase in the MAP.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 4
Correct
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Regarding local anaesthetics, which of the following statements is INCORRECT:
Your Answer: Adrenaline should be used in digital nerve blocks to create a bloodless field.
Explanation:It is not advisable to give adrenaline/epinephrine with a local anaesthetic injection in digits or appendages because of the risk of ischaemic necrosis.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 5
Correct
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Which of the following is NOT a common effect of etomidate:
Your Answer: Significant hypotension
Explanation:Etomidate causes less hypotension than thiopental sodium and propofol during induction. However, it is associated with a high incidence of extraneous muscle movements, which can be minimised by an opioid analgesic or a short-acting benzodiazepine given prior to induction. Pain on injection is common and there is a high rate of thrombophlebitis in the postoperative period. Postoperative nausea and vomiting commonly occur. Etomidate suppresses adrenocortical function, particularly during continuous administration, and it should not be used for maintenance of anaesthesia. It should be used with caution in patients with underlying adrenal insufficiency, for example, those with sepsis.
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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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Lidocaine's mechanism of action as a local aesthetic is as follows:
Your Answer: Blocks opening of ligand-gated Na+ channels
Correct Answer: Blocks influx of Na+ through voltage-gated Na+ channels
Explanation:Local anaesthetics prevent generation/conduction of nerve impulses by reducing sodium permeability and increasing action potential threshold; inhibits depolarization, which results in blockade of conduction
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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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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: Acetylcholinesterase inhibitor
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 8
Incorrect
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Which of the following is NOT a common side effect of diazepam:
Your Answer: Amnesia
Correct Answer: Bradycardia
Explanation:Adverse effects include:
Drowsiness and lightheadedness
Confusion and ataxia (especially in the elderly), amnesia, muscle weakness
Headache, vertigo, tremor, dysarthria, hypotension, decreased libido, erectile dysfunction, gynaecomastia, urinary retention
Paradoxical effects such as talkativeness, excitement, irritability, aggression, anti-social behaviour, and suicidal ideation
Withdrawal symptoms, for example anxiety, depression, anorexia, impaired concentration, insomnia, abdominal cramps, palpitations, tremor, tinnitus and perceptual disturbances
Tolerance and dependence (people who use benzodiazepines longer term can develop tolerance and eventual dependence) -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 9
Correct
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You intend to suture a hand wound with plain 1 percent lidocaine.
In 1 mL of plain 1 percent lidocaine solution, how much lidocaine hydrochloride is there?Your Answer: 10 mg lidocaine hydrochloride
Explanation:10 mg of lidocaine hydrochloride is contained in each 1 mL of plain 1 percent lidocaine solution.
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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 an effect of benzodiazepines:
Your Answer: Analgesic effect
Explanation:Benzodiazepines are gamma-aminobutyric acid (GABA) receptor agonists which enhance inhibitory synaptic transmission throughout the central nervous system, with sedative, hypnotic, anxiolytic, anticonvulsant, amnesic and muscle relaxant properties.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 11
Correct
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A 52-year-old patient requires procedural sedation for DC cardioversion of atrial fibrillation. You plan on using propofol as the sedative agent.
Propofol works as a result of action on what type of receptor? Select ONE answer only.Your Answer: Gamma-aminobutyric acid (GABA)
Explanation:Propofol (2,6-diisopropylphenol) is a short-acting phenol derivative that is primarily used for the induction of anaesthesia.
Its mechanism of action is unclear but is thought to act by potentiating the inhibitory neurotransmitters GABA and glycine, which enhances spinal inhibition during anaesthesia.
The dose for induction of anaesthesia is 1.5-2.5mg/kg. The dose for maintenance of anaesthesia is 4-12 mg/kg/hour. Following intravenous injection, propofol acts within 30 seconds and its duration of action is 5-10 minutes.
Propofol produces a 15-25% decrease in blood pressure and systemic vascular resistance without a compensatory increase in heart rate. It is negatively inotropic and decreases cardiac output by approximately 20%.
The main side effects of propofol are:
Pain on injection (in up to 30%)
Hypotension
Transient apnoea
Hyperventilation
Coughing and hiccough
Headache
Thrombosis and phlebitis -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 12
Incorrect
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For which of the following class of drugs can neostigmine be used as a reversal agent?
Your Answer: Depolarising muscle relaxants
Correct Answer: Non-depolarising muscle relaxants
Explanation:Neostigmine is used specifically for reversal of nondepolarizing (competitive) blockade and is anticholinesterase. It acts within one minute of intravenous injection, and the effects last for 20 to 30 minutes. After this time period, a second dose may then be necessary.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 13
Correct
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A young farmer who is caught under farm machinery and suffering from a major crush injury is taken to the emergency department and requires a quick induction sequence. In this type of injury, which of the following anaesthetic medicines should be avoided?
Your Answer: Suxamethonium
Explanation:Suxamethonium is a neuromuscular blocker. It is contraindicated in patients who have experienced massive trauma, hyperkalemic, or burn injuries.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 14
Incorrect
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Nitrous oxide is associated with which of the following adverse effects:
Your Answer: Hypotension
Correct Answer: Megaloblastic anaemia
Explanation:Exposure to nitrous oxide for prolonged periods, either by continuous or by intermittent administration, may result in megaloblastic anaemia as a result of interference with the action of vitamin B12; neurological toxic effects can occur without preceding overt haematological changes. Depression of white cell formation may also occur.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 15
Correct
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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: 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
Rash -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 16
Incorrect
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Which of the following statements about propofol is TRUE:
Your Answer: If accidentally injected outside a vein it can cause tissue necrosis.
Correct Answer: Propofol has some antiemetic action.
Explanation:Propofol has some antiemetic properties. It’s for this reason that it’s used to treat postoperative nausea and vomiting. Propofol is mostly processed in the liver, with the kidneys excreting just around 1% of it unaltered. Propofol, unlike thiopental, does not produce tissue necrosis when it is extravasated. Propofol lowers intracranial pressure via lowering brain metabolic rate and cerebral blood flow. Propofol is thought to be safe for people with bronchial asthma and chronic obstructive pulmonary disease.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 17
Correct
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Which of the following side effects has limited the use of etomidate as an intravenous induction agent:
Your Answer: Adrenocortical suppression
Explanation:Etomidate causes the least cardiovascular depression of the intravenous induction agents, with only a small reduction in the cardiac output and blood pressure. In the past, etomidate was widely used to induce anaesthesia in the shocked, elderly or cardiovascularly unstable patient. However, more recently it has become less popular as a single induction dose blocks the normal stress-induced increase in adrenal cortisol production for 4 – 8 hours, and up to 24 hours in elderly and debilitated patients. Although no increase in mortality has been identified following a single dose during induction of anaesthesia, the use of etomidate has declined due to a perceived potential morbidity.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 18
Correct
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In relation to ketamine, which of the following statements is TRUE:
Your Answer: It is usually associated with tachycardia, increased blood pressure and increased cardiac output.
Explanation:Ketamine has hypnotic, analgesic and local anaesthetic properties. Major adverse effects include Hypertension, Increased cardiac output, Increased ICP, Tachycardia, Tonic-clonic movements, Visual hallucinations and Vivid dreams.
Ketamine is mostly utilized in paediatric anaesthesia, especially when repeated dosing is necessary (such as for serial burns dressings). Ketamine has little effect on respiratory drive, and protective airway reflexes are unaffected. Ketamine is also a bronchial smooth muscle relaxant, hence it plays a unique function in the treatment of severe asthma. -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 19
Incorrect
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Which of the following is a contraindication to using nitrous oxide:
Your Answer: Acute porphyrias
Correct Answer: Raised intracranial pressure
Explanation:Nitrous oxide should not be utilized in patients with an air-containing confined area because it diffuses into these spaces, causing a rise in pressure. This includes circumstances like pneumothorax, intracranial air after a head injury, imprisoned air from a recent undersea dive, a recent intraocular gas injection, or intestinal blockage. Nitrous oxide increases cerebral blood flow and should be avoided in individuals who have or are at risk of having high intracranial pressure.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 20
Correct
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Naloxone is a reversal agent for which of the following groups of drugs:
Your Answer: Opioids
Explanation:Naloxone is a specific antagonist of mu(μ)-opioid receptors, the specific antidote for opioid overdose and will reverse respiratory depression and coma if given at sufficient dosage. The initial dose is usually 0.8 mg (2 mL) intravenously (the dose range suggested by BNF is 0.4-2 mg). It can also be given by intramuscular injection if the intravenous route is not feasible.
As naloxone has a shorter duration of action than most opioids, close monitoring and repeated injections are necessary according to the respiratory rate and depth of coma. The dose is generally repeated every 2-3 minutes to a maximum of 10 mg. When repeated doses are needed, naloxone may be given by a continuous infusion adjusted according to the vital signs. Initially, the infusion rate can be set at 60% of the initial resuscitative IV dose per hour.
In opioid addicts, naloxone administration may precipitate a withdrawal syndrome with abdominal cramps, nausea and diarrhoea, but these usually settle within 2 hours. -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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SESSION STATS - PERFORMANCE PER SPECIALTY
