NEET-PG 2013 - Anesthesiology PYQs Practice Questions

Q: Ether was first used as an anesthetic by?

Morton. ***Morton*** - **William T.G. Morton**, a dentist, publicly demonstrated the use of **ether as a surgical anesthetic** in 1846 during a tooth extraction at Massachusetts General Hospital. - This event marked a pivotal moment in medicine, revolutionizing surgical practices by providing effective pain relief. *Priestly* - **Joseph Priestley** was an 18th-century chemist who discovered several gases, including **oxygen**, but was not involved in the anesthetic use of ether. - His work was foundational to understanding the composition of air but did not extend to surgical applications of inhaled substances. *Wells* - **Horace Wells**, an American dentist, was an early pioneer in anesthesia who experimented with **nitrous oxide** as an anesthetic for tooth extractions. - While significant, his work predated and differed from Morton's successful public demonstration and widespread adoption of ether. *Simpson* - **James Young Simpson**, a Scottish obstetrician, is credited with pioneering the use of **chloroform** as an anesthetic, particularly in childbirth. - His contributions were later than Morton's use of ether and involved a different anesthetic agent. [Practice more Anesthesiology PYQs on OnCourse]

Q: What is the primary clinical use of Sugammadex in anesthesia?

Reversal of NM blockers. ***Reversal of NM blockers*** - **Sugammadex** is a modified gamma-cyclodextrin that specifically encapsulates steroidal **neuromuscular blocking agents (NMBAs)** like **rocuronium** and **vecuronium**. - This encapsulation rapidly inactivates the NMBAs, leading to a dose-dependent and swift **reversal of neuromuscular blockade**. *Organophosphate poisoning* - Organophosphate poisoning is treated with **atropine** to block muscarinic effects and **pralidoxime** to reactivate inhibited acetylcholinesterase. - Sugammadex has no role in antagonizing the effects of **organophosphates** or regenerating acetylcholinesterase. *Treatment of local anaesthetic poisoning* - Local anesthetic systemic toxicity (LAST) is primarily managed with supportive care, including airway management, and the administration of **lipid emulsion therapy**. - Sugammadex does not bind to local anesthetics and therefore has no efficacy in treating local anesthetic poisoning. *Treatment of central anticholinergic syndrome* - Central anticholinergic syndrome is typically treated with **physostigmine**, an acetylcholinesterase inhibitor that can cross the blood-brain barrier. - Sugammadex is not an anticholinergic antagonist and does not affect the central nervous system to reverse anticholinergic effects. [Practice more Anesthesiology PYQs on OnCourse]

Q: What is the drug of choice for reversing muscle relaxants after anesthesia?

Neostigmine. ***Neostigmine*** - **Neostigmine** is an **acetylcholinesterase inhibitor** that increases the amount of acetylcholine at the neuromuscular junction, thereby reversing the effects of non-depolarizing muscle relaxants. - It is often co-administered with an **anticholinergic agent** like atropine or glycopyrrolate to counteract its muscarinic side effects (e.g., bradycardia, increased secretions). *Pralidoxine* - **Pralidoxine (2-PAM)** is an **oxime cholinesterase reactivator** used primarily to treat organophosphate poisoning. - It works by regenerating acetylcholinesterase that has been inhibited by organophosphates, which is not the mechanism of action required for reversing typical muscle relaxants. *Atropine* - **Atropine** is an **anticholinergic drug** that blocks muscarinic acetylcholine receptors. - While it is often given with neostigmine to counteract muscarinic side effects like bradycardia, it does not directly reverse the neuromuscular blockade caused by muscle relaxants. *None of the options* - This option is incorrect because **neostigmine** is a well-established and commonly used drug for reversing non-depolarizing muscle relaxants. [Practice more Anesthesiology PYQs on OnCourse]

Q: Which anaesthetic agent has maximum MAC ?

Nitrous Oxide (N2O). ***Nitrous Oxide (N2O)*** - **Nitrous Oxide** has the highest **minimum alveolar concentration (MAC)** of all commonly used inhalational anesthetics, approximately 104%. - A high MAC indicates **low potency**, meaning that a large concentration is required to achieve anesthetic effects. *Ether* - **Ether** has a MAC of about 1.92%, which is significantly lower than that of Nitrous Oxide. - Its use has largely been replaced due to its flammability, slow induction, and recovery times. *Methoxyfluorane* - **Methoxyfluorane** is known for having a very low MAC, around 0.16%, making it the most potent inhalational anesthetic. - Due to its high potency and significant nephrotoxicity, its use is now very limited. *Halothane* - **Halothane** has a MAC of approximately 0.75%. - While it was a widely used inhalational anesthetic, it has largely been replaced due to concerns about **halothane hepatitis** and arrhythmogenicity. [Practice more Anesthesiology PYQs on OnCourse]

Q: Phase II block is seen with:

SCh infusion. ***SCh infusion*** - A **prolonged infusion or high dose** of succinylcholine (SCh) can lead to a **Phase II block**, a desensitizing block resembling that of a non-depolarizing neuromuscular blocker. - This occurs due to the **persistent presence of SCh** at the neuromuscular junction, which initially depolarizes the endplate (Phase I) but eventually leads to **receptor desensitization** and repolarization, preventing further muscle contraction. *Single dose SCh* - A **single bolus dose of succinylcholine** typically produces a **Phase I block**, characterized by initial muscle fasciculations followed by flaccid paralysis due to persistent depolarization of the motor endplate. - It resolves relatively quickly as **succinylcholine is rapidly hydrolyzed** by pseudocholinesterase, usually not leading to a prolonged desensitization characteristic of Phase II. *Mivacurium* - **Mivacurium** is an intermediate-acting, **non-depolarizing neuromuscular blocker**. - Its mechanism of action involves **competitively binding to nicotinic acetylcholine receptors** at the neuromuscular junction, thereby preventing acetylcholine from binding and initiating muscle contraction, which is fundamentally different from a Phase II block caused by prolonged depolarization. *None of the options* - This option is incorrect because **SCh infusion** is a recognized cause of Phase II block. - The phenomenon of Phase II block is a well-established pharmacological response to **excessive and prolonged exposure** to depolarizing neuromuscular blockers like succinylcholine. [Practice more Anesthesiology PYQs on OnCourse]

Question 1

Ether was first used as an anesthetic by?

Accepted Answer

Morton

Answer

Wells

Answer

Simpson

Answer

Priestly

Question 2

What is the primary clinical use of Sugammadex in anesthesia?

Accepted Answer

Reversal of NM blockers

Answer

Organophosphate poisoning

Answer

Treatment of local anaesthetic poisoning

Answer

Treatment of central anticholinergic syndrome

Question 3

What is the drug of choice for reversing muscle relaxants after anesthesia?

Accepted Answer

Neostigmine

Answer

Pralidoxine

Answer

Atropine

Answer

None of the options

Question 4

Which anaesthetic agent has maximum MAC ?

Accepted Answer

Nitrous Oxide (N2O)

Answer

Ether

Answer

Methoxyfluorane

Answer

Halothane

Question 5

Phase II block is seen with:

Accepted Answer

SCh infusion

Answer

Single dose SCh

Answer

Mivacurium

Answer

None of the options

Question 6

Central venous monitoring is typically used for all of the following except:

Accepted Answer

Administering thrombolytics

Answer

Deciding the need for plasma infusion

Answer

Deciding the requirement for blood transfusion

Answer

Regulating the speed and amount of fluid infusion

Question 7

In which vein is Central Venous Pressure (CVP) most accurately monitored?

Accepted Answer

Internal jugular vein

Answer

Anterior jugular vein

Answer

External jugular vein

Answer

Inferior vena cava

Question 8

Which of the following anesthetic agents causes the LEAST severe complications when accidentally injected intra-arterially?

Accepted Answer

Propofol

Answer

Thiopentone

Answer

Methohexitone

Answer

Midazolam

Question 9

Dissociative anaesthesia is produced by?

Accepted Answer

Ketamine

Answer

Etomidate

Answer

Propofol

Answer

Thiopentone

Question 10

Which of the following statements about Nitrous Oxide (N2O) is true?

Accepted Answer

Least potent inhalational anesthetic

Answer

Lighter than air

Answer

Effective muscle relaxant

Answer

Does not cause diffusion hypoxia

NEET-PG 2013 — Anesthesiology