General Anesthesia — MCQs

General Anesthesia Indian Medical PG Practice Questions and MCQs

Question 601: Which inhalational anesthetic is most commonly used for induction in general anesthesia?

A. Sevoflurane (Correct Answer)
B. Desflurane
C. Enflurane
D. Nitrous oxide

Explanation: ***Sevoflurane*** - **Sevoflurane** is preferred for inhalational induction due to its **low pungency** and **rapid onset** and offset of action. - Its favorable pharmacokinetic profile makes it suitable for patients of all ages, including children, for quick and smooth induction without airway irritation. *Desflurane* - **Desflurane** has a **very low blood-gas solubility**, leading to rapid onset and offset, but it is **too pungent** for inhalational induction. - Its high pungency often causes **coughing, salivation, and laryngospasm**, making it unsuitable forawake induction *Enflurane* - **Enflurane** is an older inhalational anesthetic that is **rarely used today** due to its side effects, including the potential for **seizures** and **arrhythmias**. - Its slower onset and higher incidence of adverse effects make it inferior to newer agents for induction. *Nitrous oxide* - **Nitrous oxide** is a weak anesthetic and is typically used as an adjunct to other more potent inhalational agents, not as a primary induction agent. - It has a high **MAC (Minimum Alveolar Concentration)**, meaning it cannot produce surgical anesthesia on its own.

Question 602: Which of the following statements about propofol is false?

A. Used for induction & maintenance of anesthesia
B. Causes sedation
C. Causes vomiting after use (Correct Answer)
D. Has a rapid recovery rate

Explanation: ***Causes vomiting after use*** - Propofol is actually known for its **antiemetic properties**, meaning it helps reduce or prevent nausea and vomiting after anesthesia. - This statement is false because propofol's effect is typically the opposite of causing vomiting, often being used to mitigate postoperative nausea and vomiting. *Has a rapid recovery rate* - Propofol is indeed characterized by a **rapid onset** and **rapid recovery** profile, making it a popular choice for procedures requiring quick patient awakening. - Its short duration of action is due to its **rapid redistribution** from the brain to other tissues and its high metabolic clearance. *Used for induction & maintenance of anesthesia* - Propofol is widely used as an intravenous anesthetic agent for both the **induction of general anesthesia** and for the **maintenance of anesthesia** through continuous infusion. - It provides a smooth induction and allows for dose-dependent control of anesthetic depth during maintenance. *Causes sedation* - Propofol is a potent sedative-hypnotic agent that causes dose-dependent **central nervous system depression**, leading to sedation and loss of consciousness. - This property is fundamental to its use in anesthesia and conscious sedation procedures.

Question 603: Which of the following is the most clinically significant statement about propofol?

A. None of the options
B. Safe to use in porphyria (Correct Answer)
C. It belongs to the alkyl phenol group
D. Contraindicated in patients with egg allergy

Explanation: ***Safe to use in porphyria*** - Propofol is considered **safe** for use in patients with **porphyria**, as it does not induce the enzymes involved in heme biosynthesis that can precipitate **porphyric crises**. - This represents the most **clinically significant** information about propofol, as using contraindicated anesthetics in porphyria patients can be life-threatening. *None of the options* - This option is incorrect because "Safe to use in porphyria" is a factually correct and clinically relevant statement about propofol. - Multiple statements about propofol can be correct, making this blanket dismissal inappropriate. *Not indicated in egg allergy* - While propofol contains **egg lecithin** as an emulsifier, **mild egg allergy** is not an absolute contraindication according to current guidelines. - **Severe egg allergy** may require caution and consideration of alternatives, but the statement oversimplifies the clinical reality. *It belongs to the alkyl phenol group* - This statement is **chemically correct** - propofol is indeed an **alkylphenol** compound (2,6-diisopropylphenol). - However, this pharmacological classification has limited **clinical relevance** compared to safety considerations in specific patient populations like those with porphyria.

Question 604: Which of the following inhalation anesthetics should be avoided in middle ear surgery?

A. Nitrous oxide (Correct Answer)
B. Isoflurane
C. Ether
D. Halothane

Explanation: ***Nitrous oxide*** - **Nitrous oxide** rapidly diffuses into air-containing cavities, such as the middle ear, causing an increase in pressure that can disrupt grafts and ossicles, leading to **hearing loss** or **facial nerve damage**. - Its use during tympanoplasty or stapedectomy can lead to **barotrauma** and potential complications for graft survival and successful middle ear reconstruction. *Ether* - **Ether** is an older anesthetic not commonly used today in developed countries due to its flammability, pungency, and slow onset/offset. - While it doesn't specifically cause middle ear pressure changes like nitrous oxide, its general disadvantages make it an unsuitable choice for modern surgical anesthesia. *Isoflurane* - **Isoflurane** is a volatile anesthetic that does not readily diffuse into air-filled cavities in a manner that would significantly increase middle ear pressure. - It is a commonly used intravenous anesthetic for maintaining general anesthesia and would not typically be avoided for middle ear surgery. *Halothane* - **Halothane** is a potent volatile anesthetic but is rarely used now due to concerns about **hepatotoxicity** (halothane hepatitis). - Like other volatile anesthetics (except nitrous oxide), it does not cause rapid and problematic pressure changes within the middle ear.

Question 605: Which of the following inhalational anesthetic agents is contraindicated in liver disease?

A. Methoxyflurane
B. Isoflurane
C. Ether
D. Halothane (Correct Answer)

Explanation: ***Halothane*** - **Halothane** is metabolized in the liver, and approximately 20% undergoes **oxidative metabolism**, sometimes leading to the formation of reactive intermediates. - In susceptible individuals, these metabolites can cause **immune-mediated hepatotoxicity**, known as **halothane hepatitis**, making it contraindicated in pre-existing liver disease. *Methoxyflurane* - While **methoxyflurane** is extensively metabolized by the liver, its primary concern is **nephrotoxicity** due to the release of fluoride ions, not direct hepatotoxicity that would contraindicate it in liver disease. - It is rarely used clinically today because of its significant renal side effects. *Ether* - **Ether** is minimally metabolized by the liver; most of it is eliminated unchanged via the lungs. - It is not associated with significant hepatotoxicity and is therefore not contraindicated in liver disease. *Isoflurane* - **Isoflurane** undergoes very little metabolism (less than 1%) in the liver, making it one of the safest inhalational agents for patients with liver disease. - Its low metabolic conversion means a negligible risk of producing toxic metabolites that could harm the liver.

Question 606: What are the advantages associated with the use of ketamine?

A. Rapid onset of anesthesia and analgesia
B. Bronchodilation and preserved airway reflexes
C. Cardiovascular stability with minimal respiratory depression
D. All of the above (Correct Answer)

Explanation: ***All of the above*** - Ketamine provides a unique combination of **rapid onset of anesthesia**, potent **analgesia**, and desirable physiological effects, making it versatile for various clinical scenarios. - Its ability to induce **dissociative anesthesia** while maintaining spontaneous respiration and cardiovascular stability distinguishes it from many other anesthetic agents. *Rapid onset of anesthesia and analgesia* - This is a key advantage, as ketamine quickly achieves an anesthetic state and provides robust pain relief. - Its rapid action allows for efficient induction and management in emergency settings or procedures requiring prompt intervention. *Bronchodilation and preserved airway reflexes* - Ketamine's **bronchodilatory effect** makes it a favorable choice in patients with reactive airway diseases like asthma. - The **preservation of airway reflexes** helps protect against aspiration, which is a significant benefit compared to other anesthetics that depress these reflexes. *Cardiovascular stability with minimal respiratory depression* - Ketamine typically causes an increase in **heart rate and blood pressure**, contributing to cardiovascular stability, especially in patients with compromised hemodynamics. - Compared to many other anesthetics, ketamine causes **minimal respiratory depression**, maintaining spontaneous breathing and reducing the need for mechanical ventilation.

Question 607: Which of the following drugs is most effective in preventing emergence delirium with ketamine?

A. Atropine
B. Droperidol
C. Thiopentone
D. Midazolam (Correct Answer)

Explanation: ***Midazolam*** - **Midazolam**, a short-acting **benzodiazepine**, is highly effective in preventing and treating **emergence delirium** associated with ketamine. - Benzodiazepines like midazolam work by enhancing the effect of **GABA**, leading to anxiolytic, sedative, and amnesic effects that counteract the psychomimetic side effects of ketamine. *Atropine* - **Atropine** is an **anticholinergic drug** primarily used to prevent bradycardia and reduce secretions; it has no direct role in preventing or treating ketamine-induced emergence delirium. - Its mechanism of action involves blocking **muscarinic acetylcholine receptors**, which is unrelated to the psychomimetic effects of ketamine. *Droperidol* - **Droperidol** is a **butyrophenone** (dopamine antagonist) that can cause sedation and reduce the incidence of postoperative nausea and vomiting, but it is not the primary choice for ketamine-induced emergence delirium. - While it can provide sedation, its effectiveness in specifically targeting the psychomimetic effects of ketamine is less pronounced compared to benzodiazepines. *Thiopentone* - **Thiopentone** is a **barbiturate** commonly used for induction of anesthesia due to its rapid onset and short duration of action. - Although it provides sedation and hypnosis, it is not specifically indicated or highly effective in managing or preventing the **emergence delirium** associated with ketamine.

Practice by Chapter

History of Anesthesia

Practice Questions

Preoperative Evaluation

Practice Questions

Pharmacology of Inhalational Anesthetics

Practice Questions

Pharmacology of Intravenous Anesthetics

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Neuromuscular Blocking Agents

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Airway Management

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Endotracheal Intubation

Practice Questions

Difficult Airway Algorithms

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Intraoperative Monitoring

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Depth of Anesthesia Monitoring

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Emergence from Anesthesia

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Postoperative Care

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