Anaesthesia and euthanasia techniques for experimental animals MCQs With Answer

Anaesthesia and euthanasia techniques for experimental animals MCQs With Answer

Introduction: This quiz set is designed for M.Pharm students to deepen understanding of anaesthesia and euthanasia practices in laboratory animals. It covers pharmacology of common anaesthetic agents, species-specific protocols, monitoring of anaesthetic depth, perioperative analgesia, legal and ethical considerations, and humane euthanasia methods consistent with current guidelines. Questions emphasize practical decision-making — choosing appropriate drugs, routes, dosages, and recognizing complications — rather than rote facts. Use these MCQs to test knowledge required for safe, ethical experimental work and to prepare for practical scenarios where correct anaesthetic technique and humane endpoints are essential.

Q1. What is the primary objective of providing anaesthesia in experimental animal procedures?

• To sedate the animal without affecting pain perception
• To provide analgesia, muscle relaxation, and unconsciousness
• To immobilize the animal only for handling
• To induce hypothermia for metabolic studies

Correct Answer: To provide analgesia, muscle relaxation, and unconsciousness

Q2. In rodents, loss of the righting reflex typically indicates which state during induction?

• Deep surgical anaesthesia with abolished autonomic responses
• Light sedation only, animal still responsive to pain
• General anaesthesia sufficient for many procedures (loss of consciousness)
• Terminal coma and imminent death

Correct Answer: General anaesthesia sufficient for many procedures (loss of consciousness)

Q3. What is the primary molecular target of ketamine that explains its dissociative anaesthetic action?

• GABA-A receptor agonism
• Nicotinic acetylcholine receptor blockade
• N-Methyl-D-aspartate (NMDA) receptor antagonism
• Opioid mu receptor agonism

Correct Answer: N-Methyl-D-aspartate (NMDA) receptor antagonism

Q4. According to AVMA guidelines, what is the preferred route for administering pentobarbital for euthanasia when intravenous access is available?

• Intraperitoneal injection
• Intramuscular injection
• Intravenous injection
• Subcutaneous injection

Correct Answer: Intravenous injection

Q5. When using CO2 for euthanasia of laboratory rodents, what is the recommended fill rate of the chamber to minimize distress?

• Rapid fill (100% chamber volume in <1 minute)
• Gradual fill at ~10–30% of chamber volume per minute
• Intermittent bursts of CO2 until animals collapse
• Maintain a static high concentration without displacement

Correct Answer: Gradual fill at ~10–30% of chamber volume per minute

Q6. Which agent is the specific reversal drug commonly used to antagonize the effects of alpha-2 adrenergic agonists such as medetomidine?

• Atipamezole
• Flumazenil
• Naloxone
• Physostigmine

Correct Answer: Atipamezole

Q7. What is the widely accepted maximum intraperitoneal injection volume for an adult mouse to avoid complications?

• 1 ml/kg
• 5 ml/kg
• 10 ml/kg
• 25 ml/kg

Correct Answer: 10 ml/kg

Q8. Which reflex is most commonly used to assess an appropriate surgical plane of anaesthesia in small rodents?

• Pupillary light reflex
• Pedal withdrawal (toe pinch) reflex
• Cough reflex
• Righting reflex

Correct Answer: Pedal withdrawal (toe pinch) reflex

Q9. Which injectable combination is commonly used to produce reliable anaesthesia with analgesia and muscle relaxation in rodents for surgical procedures?

• Ketamine + Xylazine
• Propofol + Midazolam
• Isoflurane + Nitrous oxide
• Pentobarbital alone at sedative dose

Correct Answer: Ketamine + Xylazine

Q10. What does the Minimum Alveolar Concentration (MAC) of an inhalational anaesthetic represent?

• Concentration that induces anaesthesia in 100% of animals
• Alveolar concentration that prevents movement in response to a noxious stimulus in 50% of animals
• Minimum concentration that produces analgesia but not unconsciousness
• Maximum safe concentration tolerated by the cardiovascular system

Correct Answer: Alveolar concentration that prevents movement in response to a noxious stimulus in 50% of animals

Q11. Which euthanasia method is considered unacceptable unless the animal is first rendered deeply unconscious or anesthetized?

• CO2 euthanasia with gradual fill
• Intravenous pentobarbital overdose
• Administration of potassium chloride to a conscious animal
• Inhalant anaesthetic overdose in an induction chamber

Correct Answer: Administration of potassium chloride to a conscious animal

Q12. For preemptive analgesia in rodents undergoing minor to moderate surgical procedures, which opioid is commonly recommended because of its duration and safety?

• Morphine
• Buprenorphine
• Fentanyl patch
• Codeine

Correct Answer: Buprenorphine

Q13. Why is an induction chamber often preferred for initiating gaseous anaesthesia in small rodents?

• It allows precise intravenous dosing during induction
• It reduces handling stress and permits controlled gas concentration exposure
• It guarantees immediate unconsciousness without any monitoring
• It is the only method approved for all species

Correct Answer: It reduces handling stress and permits controlled gas concentration exposure

Q14. Approximately how long does a single intraperitoneal dose of ketamine alone typically provide anaesthesia in a mouse?

• 5–10 minutes
• 20–30 minutes
• 2–3 hours
• 24 hours

Correct Answer: 20–30 minutes

Q15. What is the recommendation regarding preoperative fasting of mice before routine anaesthesia?

• Mice should be fasted for 12–24 hours to reduce aspiration risk
• Mice should be fasted overnight but water provided
• Prolonged fasting is not recommended due to high metabolic rate and risk of hypoglycaemia
• Mice must be fasted for 48 hours prior to anaesthesia

Correct Answer: Prolonged fasting is not recommended due to high metabolic rate and risk of hypoglycaemia

Q16. If neuromuscular blocking agents are administered during an experiment, what essential supportive measure must be provided?

• Analgesics are optional since blocks remove pain
• Supplemental oxygen is sufficient without further monitoring
• Mechanical ventilation or assisted ventilation to maintain respiration
• Continuous administration of volatile anaesthetics only

Correct Answer: Mechanical ventilation or assisted ventilation to maintain respiration

Q17. Which inhalational anaesthetic is most classically associated with rare but severe hepatic necrosis (halothane hepatitis) in susceptible species?

• Isoflurane
• Sevoflurane
• Halothane
• Nitrous oxide

Correct Answer: Halothane

Q18. Which combination of findings best confirms death following a euthanasia procedure in small laboratory animals?

• Absence of vocalization and muscle tone
• Absence of heartbeat and respiration and lack of corneal reflex
• Loss of righting reflex and decreased temperature
• Fixed pupils only

Correct Answer: Absence of heartbeat and respiration and lack of corneal reflex

Q19. Which drug is the specific antagonist used to reverse benzodiazepine-induced sedation in experimental animals?

• Naloxone
• Flumazenil
• Atropine
• Neostigmine

Correct Answer: Flumazenil

Q20. Which agent is most commonly used for chemical euthanasia because it reliably induces rapid unconsciousness followed by respiratory and cardiac arrest when given in overdose?

• Sodium pentobarbital
• Ketamine at clinical dose
• Xylazine alone
• Isoflurane at maintenance concentration

Correct Answer: Sodium pentobarbital

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