General Anesthesia Practice Questions

Q: Muscle relaxant ideal for rapid intubation and short procedures is:

Rocuronium. ***Rocuronium*** - **Rocuronium** has a rapid onset of action (60-90 seconds) and an intermediate duration of action (30-60 minutes), making it suitable for rapid sequence intubation. - Its effects can be rapidly reversed by **sugammadex**, allowing for controlled and quick recovery when needed for short procedures. *Atracurium* - **Atracurium** has an intermediate onset (2-3 minutes) and duration of action (20-35 minutes), which is slower than ideal for rapid intubation. - It undergoes **Hofmann elimination** and ester hydrolysis, making it suitable for patients with renal or hepatic dysfunction, but not primarily for rapid onset. *Suxamethonium* - **Suxamethonium** (succinylcholine) has the most rapid onset of action (30-60 seconds) among muscle relaxants, historically making it the drug of choice for rapid sequence intubation. - However, its side effects, such as **malignant hyperthermia**, hyperkalemia, and prolonged paralysis in patients with atypical pseudocholinesterase, limit its use where alternative agents like rocuronium are available and suitable. *Vecuronium* - **Vecuronium** has an intermediate onset (2-3 minutes) and duration of action (25-40 minutes), making it too slow for rapid sequence intubation. - It is often chosen for its minimal cardiovascular effects and moderate duration, making it suitable for procedures where a longer duration of paralysis is acceptable, but not for rapid intubation.

Q: Which one of the following is a Nephrotoxic anaesthetic agent ?

Methoxyflurane. ***Methoxyflurane*** - **Methoxyflurane** is an inhaled anesthetic that can cause dose-dependent **nephrotoxicity** due to the metabolic release of **fluoride ions**. - Its use is limited due to the risk of **renal dysfunction**, including **high-output renal failure**, especially with prolonged administration or high concentrations. *Nitrous oxide* - **Nitrous oxide** is an inhaled anesthetic known for its analgesic properties and low solubility, leading to rapid onset and offset. - It does not typically cause **direct organ toxicity** like nephrotoxicity, though prolonged exposure can affect bone marrow. *Halothane* - **Halothane** is an older inhaled anesthetic associated with **hepatotoxicity** (halothane hepatitis) in some susceptible individuals. - While it can cause liver damage, it is not primarily known for causing **nephrotoxicity**. *Isoflurane* - **Isoflurane** is a commonly used inhaled anesthetic known for its relatively stable cardiovascular effects and low metabolic degradation. - It is generally considered to have a **good safety profile** with minimal organ toxicity, including the kidneys.

Q: A patient with mild to moderate renal failure requires reversal of muscle relaxation induced by vecuronium. Which of the following drugs is appropriate for this purpose?

Sugammadex. ***Sugammadex*** - **Sugammadex** is a modified gamma-cyclodextrin that forms a tight, water-soluble complex with **steroidal non-depolarizing neuromuscular blocking agents** like vecuronium, effectively encapsulating and inactivating them. - Its elimination is primarily renal, but even in **mild to moderate renal failure**, its rapid binding to vecuronium and lack of active metabolites make it a safe and effective choice for reversal. *Physostigmine* - **Physostigmine** is an anticholinesterase that indirectly increases acetylcholine at the neuromuscular junction, but it is not commonly used for reversing **neuromuscular blockade** due to its widespread muscarinic and nicotinic effects. - It can cause significant side effects like **bradycardia**, **bronchospasm**, and increased secretions, and its efficacy for non-depolarizing blockers is limited. *Rivastigmine* - **Rivastigmine** is an **acetylcholinesterase inhibitor** primarily used in the treatment of **Alzheimer's disease** and Parkinson's disease dementia. - It does not have a role in reversing neuromuscular blockade induced by vecuronium. *Succinylcholine* - **Succinylcholine** is a **depolarizing neuromuscular blocker** itself, causing muscle relaxation rather than reversing it. - It would prolong paralysis rather than reverse the effects of vecuronium.

Q: Arrange the following anesthetic agents based on their potency Nitrous oxide Halothane Isoflurane Methoxyflurane

Methoxyflurane > Halothane > Isoflurane > Nitrous oxide. ***Methoxyflurane > Halothane > Isoflurane > Nitrous oxide*** - Anesthetic potency is inversely related to its **MAC (Minimum Alveolar Concentration)** value. A lower MAC value indicates higher potency. - The MAC values for these agents are: Methoxyflurane (0.16%), Halothane (0.75%), Isoflurane (1.15%), and Nitrous oxide (104%), which directly corresponds to this order of potency. *Methoxyflurane > Nitrous oxide > Halothane > Isoflurane* - This order incorrectly places nitrous oxide as more potent than halothane and isoflurane. **Nitrous oxide** has a very high MAC (104%), indicating low potency. - **Halothane** and **isoflurane** have significantly lower MAC values (0.75% and 1.15%, respectively), making them much more potent than nitrous oxide. *Methoxyflurane > Isoflurane > Halothane > Nitrous oxide* - This order incorrectly places **isoflurane** as more potent than halothane. **Halothane** has a MAC of 0.75%, while **isoflurane** has a MAC of 1.15%. - Therefore, halothane is more potent than isoflurane, making this sequence incorrect. *Halothane > Isoflurane > Nitrous oxide > Methoxyflurane* - This order incorrectly places **halothane** as the most potent and **methoxyflurane** as the least potent among the listed agents. - **Methoxyflurane** has the lowest MAC (0.16%), making it the most potent, while **nitrous oxide** has the highest MAC (104%), making it the least potent.

Q: Which of the following drugs is used for hypotensive anesthesia:

Both Isoflurane and Nitroglycerin. ***Both Isoflurane and Nitroglycerin*** - **Isoflurane** is a volatile anesthetic that can induce **hypotension** by decreasing systemic vascular resistance and myocardial contractility. - **Nitroglycerin** is a potent vasodilator that primarily acts on veins, but also on arteries, to reduce preload and afterload, thereby lowering blood pressure. *Isoflurane* - While **Isoflurane** can be used as part of a hypotensive anesthesia strategy, it is not the sole drug capable of achieving this effect. - Its hypotensive action is dose-dependent and results from **vasodilation** and direct **myocardial depression**. *Nitroglycerin* - **Nitroglycerin** is effective in inducing controlled **hypotension** due to its rapid onset and short duration of action as a vasodilator. - It is frequently used in anesthesia for its ability to reduce blood pressure, particularly in situations requiring a **dry surgical field**. *Dantrolene* - **Dantrolene** is a skeletal muscle relaxant primarily used to treat and prevent **malignant hyperthermia**. - It does not directly induce **hypotension** and is not indicated for hypotensive anesthesia.

Q: Which of the following inhalational anaesthetic agent can cause hepatitis on repeated use?

Halothane. ***Halothane*** - Halothane is known to cause **halothane hepatitis** (also known as halothane-induced liver injury), a rare but severe form of liver damage, particularly on **repeated exposure**. - This is due to the **metabolism of halothane** in the liver, which can produce reactive intermediates that lead to immune-mediated liver cell necrosis. *Sevoflurane* - Sevoflurane is generally considered to have a **low incidence of liver toxicity** and is preferred in patients with pre-existing liver disease. - While it can be metabolized to fluoride ions, the clinical significance of this in terms of liver damage is considered to be minimal compared to halothane. *Ether* - **Diethlyl ether** is an older anesthetic agent that is no longer commonly used due to its flammability and slower induction/recovery times. - While it can cause some hepatic dysfunction, it is not primarily associated with the severe, immune-mediated hepatitis seen with halothane. *Isoflurane* - Isoflurane is an ether-based anesthetic with a much **lower metabolism** rate than halothane. - This reduced metabolism contributes to its **lower potential for liver toxicity** compared to halothane, making it a safer option for patients with liver concerns.

Q: Which of the following is the most suitable anesthetic agent for use in dogs?

Propofol. ***Propofol*** - **Propofol** is a widely used and highly effective intravenous anesthetic in dogs due to its **rapid induction** and **rapid recovery**. - It produces minimal cumulative effects when administered as a constant rate infusion, making it suitable for both short procedures and maintenance of anesthesia. *Medetomidine hydrochloride* - **Medetomidine** is an **alpha-2 agonist** primarily used as a sedative and analgesic in dogs, not typically as the sole anesthetic agent for general anesthesia. - While it provides profound sedation, it is usually combined with other drugs (e.g., ketamine) to achieve surgical planes of anesthesia, and its effects on reducing heart rate and blood pressure can be significant. *Ketamine* - **Ketamine** is a **dissociative anesthetic** that provides good analgesia and somatic anesthesia but often causes muscle rigidity and can increase sympathetic tone. - It is typically used in combination with other sedatives or tranquilizers (e.g., diazepam, midazolam) to ensure smooth induction and recovery and prevent adverse effects like seizures. *Midazolam* - **Midazolam** is a **benzodiazepine** primarily used as a sedative, anxiolytic, and muscle relaxant, often as a premedicant or co-induction agent, not as a primary anesthetic for general anesthesia in dogs. - It offers minimal cardiovascular and respiratory depression when used alone, but it does not produce sufficient anesthetic depth for surgical procedures.

Q: Dose of ketamine by IM route is (in mg/kg) –

4. ***4*** - The standard recommended dose for **intramuscular (IM) administration of ketamine** for sedation or anesthesia induction is typically **4 mg/kg**. - This dose usually provides effective sedation and analgesia with a relatively rapid onset of action. *10* - A dose of **10 mg/kg IM ketamine** is generally considered too high for routine clinical use, increasing the risk of adverse effects such as **prolonged recovery, significant emergence reactions, and respiratory depression**. - This dose may be used in specific, carefully controlled situations, but it is not the standard initial dose. *6* - While **6 mg/kg IM ketamine** might be effective, it is on the higher side compared to the most commonly cited standard of 4 mg/kg. - Using a slightly lower standard dose like 4 mg/kg helps to minimize potential side effects, especially in patients who may be more sensitive to the drug. *8* - A dose of **8 mg/kg IM ketamine** is considerably higher than the typical recommended dose and would significantly increase the likelihood of **adverse effects** such as profound hallucinations, agitation, and cardiovascular stimulation. - Such high doses are not routinely used for IM administration in general practice.

Q: A patient on atracurium develops seizures due to accumulation of

Laudanosine. ***Laudanosine*** - **Laudanosine** is a metabolite of atracurium which is known to cross the **blood-brain barrier** and can cause **seizures** and central nervous system excitation, especially in high concentrations or in patients with impaired renal or hepatic function. - Atracurium undergoes **Hofmann elimination** and **ester hydrolysis** to produce laudanosine and other inactive metabolites. *Sulfated Atracurium* - **Atracurium** is not primarily metabolized through sulfation; its primary degradation pathways are **Hofmann elimination** and **ester hydrolysis**. - There is no known direct association between sulfated atracurium and seizure activity. *Hofmann elimination products* - **Hofmann elimination** is one of the main pathways for atracurium degradation, but the *overall products* are numerous, and **laudanosine** is the specific metabolite implicated in seizures. - While laudanosine is a product of Hofmann elimination, this option is too broad and does not pinpoint the neurotoxic metabolite. *Ester hydrolysis products* - **Ester hydrolysis** is another significant pathway for atracurium metabolism, but, similar to Hofmann elimination, it produces various metabolites. - **Laudanosine** is formed via Hofmann elimination; ester hydrolysis primarily produces quaternary acid and alcohol products, which are not directly linked to seizure activity.

Q: Which muscle is most resistant to neuromuscular blockage?

Diaphragm. ***Diaphragm*** - The **diaphragm** is functionally resistant to neuromuscular blocking agents due to its high density of acetylcholine receptors and different isoform of nicotinic receptors. - Due to its vital role in respiration, it is the last muscle to be paralyzed and the first to recover from neuromuscular blockade. *Adductor pollicis* - The **adductor pollicis** is a commonly used muscle for monitoring neuromuscular blockade as it is highly sensitive to the effects of these agents. - Its response correlates well with the blockade of muscles in the **larynx and pharynx**, making it a good indicator for intubation conditions. *Ocular* - **Ocular muscles** are among the first muscles to be affected by neuromuscular blockers. - They tend to show partial recovery while other muscles are still significantly blocked, reflecting their high metabolic rate and sparse acetylcholine receptor distribution. *Intercostal muscles* - **Intercostal muscles** are accessory muscles of respiration that are more sensitive to neuromuscular blockade than the diaphragm. - They are paralyzed relatively early in the process and recover later than the diaphragm, leading to reduced tidal volume even when the diaphragm is functional.

Question 1

Muscle relaxant ideal for rapid intubation and short procedures is:

Accepted Answer

Rocuronium

Answer

Atracurium

Answer

Suxamethonium

Answer

Vecuronium

Question 2

Which one of the following is a Nephrotoxic anaesthetic agent ?

Accepted Answer

Methoxyflurane

Answer

Nitrous oxide

Answer

Halothane

Answer

Isoflurane

Question 3

A patient with mild to moderate renal failure requires reversal of muscle relaxation induced by vecuronium. Which of the following drugs is appropriate for this purpose?

Accepted Answer

Sugammadex

Answer

Physostigmine

Answer

Rivastigmine

Answer

Succinylcholine

Question 4

Arrange the following anesthetic agents based on their potency
Nitrous oxide
Halothane
Isoflurane
Methoxyflurane

Accepted Answer

Methoxyflurane > Halothane > Isoflurane > Nitrous oxide

Answer

Methoxyflurane > Nitrous oxide > Halothane > Isoflurane

Answer

Methoxyflurane > Isoflurane > Halothane > Nitrous oxide

Answer

Halothane > Isoflurane > Nitrous oxide > Methoxyflurane

Question 5

Which of the following drugs is used for hypotensive anesthesia:

Accepted Answer

Both Isoflurane and Nitroglycerin

Answer

Isoflurane

Answer

Nitroglycerin

Answer

Dantrolene

Question 6

Which of the following inhalational anaesthetic agent can cause hepatitis on repeated use?

Accepted Answer

Halothane

Answer

Sevoflurane

Answer

Ether

Answer

Isoflurane

Question 7

Which of the following is the most suitable anesthetic agent for use in dogs?

Accepted Answer

Propofol

Answer

Medetomidine hydrochloride

Answer

Ketamine

Answer

Midazolam

Question 8

Dose of ketamine by IM route is (in mg/kg) –

Accepted Answer

4

Answer

10

Answer

6

Answer

8

Question 9

A patient on atracurium develops seizures due to accumulation of

Accepted Answer

Laudanosine

Answer

Sulfated Atracurium

Answer

Hofmann elimination products

Answer

Ester hydrolysis products

Question 10

Which muscle is most resistant to neuromuscular blockage?

Accepted Answer

Diaphragm

Answer

Adductor pollicis

Answer

Ocular

Answer

Intercostal muscles

General Anesthesia — MCQs

General Anesthesia — MCQs

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