General Anesthesia Practice Questions

Q: Ketamine can be used in all of the following situations except:

Ischemic heart disease. **Explanation:** Ketamine is a unique anesthetic agent that acts as an NMDA receptor antagonist. Its clinical utility and contraindications are primarily governed by its effect on the sympathetic nervous system. **Why Ischemic Heart Disease (IHD) is the Correct Answer:** Ketamine is a **sympathomimetic** agent. It inhibits the reuptake of catecholamines (norepinephrine), leading to an increase in heart rate, cardiac output, and arterial blood pressure. In patients with **Ischemic Heart Disease**, this increases myocardial oxygen demand, which can precipitate myocardial infarction or worsen ischemia. Therefore, it is strictly contraindicated in IHD and severe hypertension. **Analysis of Incorrect Options:** * **Status Asthmaticus:** Ketamine is a potent **bronchodilator**. It is often the induction agent of choice for patients with reactive airway disease or life-threatening asthma. * **Analgesia and Sedation:** Ketamine produces **"Dissociative Anesthesia"** (sensory loss with amnesia). At sub-anesthetic doses, it provides excellent analgesia without significant respiratory depression, making it ideal for short procedures and burn dressings. * **Obstetric Hemorrhage:** Ketamine is preferred in hemorrhagic shock because its sympathomimetic effects help maintain blood pressure. Unlike most induction agents, it does not cause myocardial depression in a healthy heart. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** For induction in patients with **Hypovolemic/Hemorrhagic shock** and **Bronchial Asthma**. * **Hallucinations:** Associated with "Emergence Delirium" (vivid dreams/hallucinations), which can be prevented by co-administering **Benzodiazepines** (e.g., Midazolam). * **Intracranial Pressure (ICP):** Traditionally avoided in head injuries as it increases ICP and Intraocular pressure. * **Secretions:** It increases salivation (Sialagogue effect); pretreatment with Atropine or Glycopyrrolate may be needed.

Q: All of the following are true about fospropofol EXCEPT:

It causes pain on injection, similar to propofol.. **Explanation:** Fospropofol is a water-soluble **prodrug** of propofol, developed to overcome the limitations of the lipid emulsion formulation of propofol. **1. Why Option D is the Correct Answer (The False Statement):** Unlike propofol, which is highly lipid-soluble and formulated in an emulsion that causes significant **pain on injection**, fospropofol is **water-soluble**. Because it does not require a lipid vehicle and is inactive until metabolized, it **does not cause pain at the injection site**. This is one of its primary clinical advantages. Instead of injection pain, patients often experience transient **paresthesia or pruritus** (commonly in the perineal region). **2. Analysis of Other Options:** * **Option A:** Fospropofol is indeed a water-soluble phosphate ester. It is metabolized by the enzyme **alkaline phosphatase** in the blood and liver into propofol, phosphate, and formaldehyde. * **Option B:** Because it is a prodrug requiring enzymatic conversion, its **onset of action is significantly slower** (approx. 4–8 minutes) compared to propofol (approx. 30–60 seconds). * **Option C:** The conversion process and larger volume of distribution lead to a **slower recovery/offset** compared to the rapid emergence seen with propofol. **Clinical Pearls for NEET-PG:** * **Metabolism:** 1 mg of fospropofol yields 0.54 mg of propofol. * **Indication:** Primarily used for **monitored anesthesia care (MAC)** or sedation during diagnostic procedures (e.g., colonoscopy). * **Side Effects:** Perineal pruritus is a classic "buzzword" side effect associated with fospropofol. * **Advantage:** No risk of lipid-related complications like hypertriglyceridemia or Propofol Infusion Syndrome (PRIS).

Q: What is the ideal inhalational inducing agent of choice?

Sevoflurane. **Explanation:** The ideal inhalational inducing agent must be non-irritating to the airways and have a rapid onset of action. **Sevoflurane** is the agent of choice for inhalational induction because it possesses a **low blood-gas partition coefficient (0.65)**, ensuring rapid induction and recovery, and is **non-pungent**. Unlike other agents, it does not cause coughing, breath-holding, or laryngospasm, making it particularly ideal for pediatric anesthesia where intravenous access may be difficult to establish initially. **Analysis of Incorrect Options:** * **Halothane (A):** Historically used for induction due to its pleasant odor, it is no longer the "ideal" choice because of its slow onset (higher blood-gas solubility), potential for "Halothane Hepatitis," and its tendency to sensitize the myocardium to catecholamines, leading to arrhythmias. * **Desflurane (B):** Although it has the fastest onset/offset (lowest blood-gas solubility of 0.42), it is **highly pungent** and an airway irritant. It causes coughing and tachycardia, making it unsuitable for induction. * **Isoflurane (D):** Like Desflurane, Isoflurane is pungent and can trigger airway reflexes. It is primarily used for maintenance rather than induction. **High-Yield Clinical Pearls for NEET-PG:** * **Agent of choice for Day Care Surgery:** Sevoflurane or Desflurane (due to rapid recovery). * **Soda Lime Reaction:** Sevoflurane reacts with soda lime to produce **Compound A** (nephrotoxic in rats, though clinical significance in humans is debated). * **Induction Speed:** Inversely proportional to the Blood-Gas Partition Coefficient. * **Potency:** Directly proportional to Lipid Solubility (Meyer-Overton Hypothesis) and inversely proportional to MAC (Minimum Alveolar Concentration).

Q: Which of the following inhalational agents potentiates neuromuscular blockers the most?

Desflurane. ### Explanation **Concept:** All volatile inhalational anesthetics potentiate the action of non-depolarizing neuromuscular blocking agents (NDMRs) by decreasing the sensitivity of the post-junctional membrane to acetylcholine and increasing skeletal muscle blood flow. The degree of potentiation is directly proportional to the **lipid solubility** and the **MAC (Minimum Alveolar Concentration) hours** of the agent used. **Why Desflurane is Correct:** The order of potentiation of neuromuscular blockade by inhalational agents is: **Desflurane > Sevoflurane > Isoflurane > Halothane > Nitrous Oxide.** Desflurane provides the greatest enhancement of NDMRs, allowing for a significant reduction (up to 30-50%) in the required dose of the muscle relaxant to achieve the same level of surgical blockade. **Analysis of Incorrect Options:** * **A. Halothane:** It has the least potentiating effect among the volatile liquids. It is a potent bronchodilator but has minimal effect on the neuromuscular junction compared to ethers. * **B. Isoflurane:** While it potentiates NDMRs significantly more than halothane, it is less potent in this regard than the newer fluorinated ethers like Sevoflurane and Desflurane. * **C. Sevoflurane:** It significantly potentiates NDMRs (more than Isoflurane), but clinical studies consistently rank Desflurane as the most potent enhancer of the bunch. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Potentiation occurs via central effect on alpha-motor neurons and peripheral effect at the nicotinic ACh receptors. * **Dose Reduction:** When using Desflurane, the dose of vecuronium or rocuronium should be reduced to prevent prolonged recovery. * **Exception:** Nitrous Oxide (N₂O) does **not** significantly potentiate neuromuscular blockers. * **Mnemonic:** Remember **"D-S-I-H"** (Des > Sevo > Iso > Halo) for the decreasing order of muscle relaxant potentiation.

Q: Which of the following is NOT a direct effect of a neuromuscular blocker?

Muscle relaxation. **Explanation:** The core principle of balanced anesthesia involves three distinct components: **Amnesia** (loss of memory), **Analgesia** (loss of pain), and **Muscle Relaxation**. **Why "Muscle Relaxation" is the correct answer:** The question asks for the **direct** effect of a neuromuscular blocker (NMB). NMBs (like Succinylcholine or Vecuronium) act specifically at the nicotinic acetylcholine receptors at the neuromuscular junction to inhibit skeletal muscle contraction. Therefore, muscle relaxation is the primary, direct intended effect of these drugs. **Analysis of Incorrect Options:** * **Amnesia & D. Narcosis:** NMBs are quaternary ammonium compounds; they are highly ionized and lipid-insoluble. Consequently, they **do not cross the blood-brain barrier**. They have no effect on the Central Nervous System (CNS) and provide zero sedation, hypnosis, or forgetfulness. A patient given only an NMB would be paralyzed but fully awake and aware. * **Analgesia:** NMBs do not possess any pain-relieving properties. They do not act on opioid receptors or nociceptive pathways. **NEET-PG High-Yield Pearls:** * **The "Awareness" Danger:** Administering an NMB without adequate induction agents (like Propofol) or inhalational anesthetics leads to "accidental awareness under general anesthesia," a traumatic clinical scenario. * **Monitoring:** The effect of NMBs is monitored clinically using a **Train-of-Four (TOF)** stimulator. * **Reversal:** Non-depolarizing NMBs are reversed using Acetylcholinesterase inhibitors (Neostigmine) or selective relaxant binding agents (Sugammadex). * **Order of Blockade:** Small, rapidly moving muscles (eyes, fingers) are paralyzed first, followed by limbs, and finally the **diaphragm** (which is also the first to recover).

Question 1

A seventy-year-old patient is posted for a surgery likely to last 4-6 hours. What is the best inhalational agent of choice for maintenance of anesthesia in this case?

Accepted Answer

Desflurane

Answer

Methoxyflurane

Answer

Sevoflurane

Answer

Trichlorethylene

Question 2

Which inhaled anesthetic has the least diffusion coefficient?

Accepted Answer

Nitrous Oxide (N2O)

Answer

Isoflurane

Answer

Enflurane

Answer

Halothane

Question 3

Ketamine can be used in all of the following situations except:

Accepted Answer

Ischemic heart disease

Answer

Status asthmaticus

Answer

Analgesia and sedation

Answer

Obstetric hemorrhage

Question 4

All of the following are true about fospropofol EXCEPT:

Accepted Answer

It causes pain on injection, similar to propofol.

Answer

It is a water-soluble product that is metabolized in vivo to propofol.

Answer

It has a slower onset than propofol.

Answer

It has slower recovery than propofol.

Question 5

What is the ideal inhalational inducing agent of choice?

Accepted Answer

Sevoflurane

Answer

Halothane

Answer

Desflurane

Answer

Isoflurane

Question 6

Regarding isoflurane, all of the following are true except?

Accepted Answer

It is implicated in causing seizures.

Answer

It is a respiratory depressant.

Answer

It causes tachycardia.

Answer

It is metabolized to inorganic fluoride ions.

Question 7

Which of the following inhalational agents potentiates neuromuscular blockers the most?

Accepted Answer

Desflurane

Answer

Halothane

Answer

Isoflurane

Answer

Sevoflurane

Question 8

Which of the following is NOT a direct effect of a neuromuscular blocker?

Accepted Answer

Muscle relaxation

Answer

Amnesia

Answer

Analgesia

Answer

Narcosis

Question 9

Sodium thiopentone is ultra-short acting due to which of the following mechanisms?

Accepted Answer

Rapid redistribution

Answer

Rapid absorption

Answer

Rapid metabolism

Answer

Rapid excretion

Question 10

A patient has hypersensitivity to neostigmine. Which muscle relaxant is the drug of choice for this patient undergoing upper abdominal surgery?

Accepted Answer

Atracurium

Answer

Pancuronium

Answer

Ropacuronium

Answer

Vecuronium

General Anesthesia — MCQs

General Anesthesia — MCQs

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