General Anesthesia Practice Questions

Q: Which of the following statements regarding Non-Depolarizing Muscle Relaxants is FALSE?

Non-depolarizing agents trigger malignant hyperthermia.. ### Explanation **1. Why Option D is the Correct (False) Statement:** Malignant Hyperthermia (MH) is a pharmacogenetic hypermetabolic state triggered exclusively by **volatile inhalational anesthetics** (e.g., Halothane, Isoflurane) and the **depolarizing** muscle relaxant **Succinylcholine**. Non-depolarizing muscle relaxants (NDMRs) like Vecuronium, Atracurium, and Pancuronium do **not** trigger MH. In fact, NDMRs are considered safe alternatives for patients susceptible to MH. **2. Analysis of Other Options:** * **Option A (True):** Vecuronium is primarily metabolized by the liver and excreted via bile (40-70%). While a small portion is excreted renally, it is considered relatively safe in renal failure compared to long-acting agents like Pancuronium. (Note: Cisatracurium is the gold standard for renal failure due to Hofmann elimination). * **Option B (True):** Aminoglycosides (e.g., Gentamicin, Neomycin) inhibit the pre-junctional release of Acetylcholine and decrease post-junctional sensitivity. This synergistically **potentiates** the blockade of NDMRs, especially in renal failure where drug clearance is reduced. * **Option C (True):** Pancuronium is a long-acting NDMR that possesses **vagolytic** properties (blocks muscarinic receptors in the SA node), leading to tachycardia and hypertension. **3. High-Yield Clinical Pearls for NEET-PG:** * **Hofmann Elimination:** A non-enzymatic, pH and temperature-dependent degradation unique to **Atracurium** and **Cisatracurium**, making them the drugs of choice in liver and kidney failure. * **Mivacurium:** The only NDMR metabolized by **pseudocholinesterase**. * **Rocunorium:** Has the fastest onset among NDMRs, making it suitable for Rapid Sequence Induction (RSI) when Succinylcholine is contraindicated. * **Reversal:** Sugammadex specifically reverses aminosteroid NDMRs (Rocunorium > Vecuronium).

Q: Polygelin content is found in which of the following fluids?

Haemaccel. **Explanation:** **Haemaccel** is a synthetic colloid used for volume replacement. It is specifically composed of **Polygeline**, which is a polymer of degraded gelatin cross-linked with urea. It has a molecular weight of approximately 30,000 Daltons and is unique because it contains significant concentrations of electrolytes, specifically **Calcium (6.25 mmol/L)** and Potassium. **Analysis of Options:** * **Gelofuscine (Option A):** This is also a gelatin-based colloid, but it consists of **succinylated gelatin** in isotonic saline. Unlike Haemaccel, it does not contain calcium and is not cross-linked with urea. * **Hartmann's Solution (Option B):** This is a crystalloid, also known as **Ringer's Lactate**. It contains sodium chloride, sodium lactate, potassium chloride, and calcium chloride, but no gelatin or polygeline. * **Hetastarch (Option D):** This is a **Hydroxyethyl Starch (HES)**, a synthetic colloid derived from amylopectin. It is a glucose polymer, not a protein/gelatin derivative. **High-Yield Clinical Pearls for NEET-PG:** 1. **Calcium Content:** Because Haemaccel contains calcium, it should **not** be infused through the same line as citrated blood, as it may cause clotting (recalcification of blood). 2. **Anaphylaxis:** Gelatins (Haemaccel and Gelofuscine) have a higher incidence of anaphylactoid reactions compared to starches or crystalloids due to histamine release. 3. **Renal Safety:** Unlike older Hydroxyethyl starches, polygelins have a minimal effect on renal function and coagulation profiles. 4. **Metabolism:** Polygelin is primarily excreted unchanged by the kidneys.

Q: Which of the following is the fastest acting anesthetic agent?

Sevoflurane. **Explanation:** The speed of induction and recovery of an inhalational anesthetic agent is primarily determined by its **Blood-Gas Partition Coefficient (λ)**. A lower coefficient indicates lower solubility in blood, allowing the partial pressure of the gas in the alveoli to rise rapidly, leading to faster equilibration with the brain. **Why Sevoflurane is the Correct Answer:** While **Desflurane** actually has a lower blood-gas partition coefficient (0.42) than **Sevoflurane** (0.65), Sevoflurane is clinically considered the fastest agent for **inhalation induction**. This is because Desflurane is highly pungent and irritates the airway, causing coughing, breath-holding, and laryngospasm, making it unsuitable for rapid mask induction. Sevoflurane is non-pungent, pleasant-smelling, and a potent bronchodilator, allowing for a smooth and rapid "single-breath" induction, especially in pediatric practice. **Analysis of Incorrect Options:** * **B. Desflurane:** Although it has the fastest *emergence* (recovery) due to its lowest solubility, its pungency prevents it from being the fastest agent for *induction*. * **C. Isoflurane:** It has a higher blood-gas partition coefficient (1.4), making it significantly slower in both induction and recovery compared to Sevoflurane and Desflurane. **High-Yield Clinical Pearls for NEET-PG:** * **Lowest Blood-Gas Coefficient:** Desflurane (0.42) > Sevoflurane (0.65) > Nitrous Oxide (0.47) > Isoflurane (1.4) > Halothane (2.4). * **Agent of Choice for Induction:** Sevoflurane (due to non-pungency). * **Agent of Choice for Maintenance in Day-care Surgery:** Desflurane (due to fastest recovery). * **Compound A:** A nephrotoxic byproduct formed when Sevoflurane reacts with dry soda lime. * **Carbon Monoxide:** Highest production is seen with Desflurane when used with dry CO2 absorbers.

Q: Which of the following solutions is a colloid?

Albumin. **Explanation:** Intravenous fluids are broadly classified into two categories: **Crystalloids** and **Colloids**, based on their molecular weight and ability to cross the semi-permeable capillary membrane. **Why Albumin is the Correct Answer:** **Albumin** is a natural **colloid**. Colloids contain large, high-molecular-weight molecules (usually >30,000 Daltons) that do not easily cross the healthy capillary endothelium. Because they remain within the intravascular compartment, they exert **oncotic pressure**, effectively drawing fluid into or maintaining fluid within the blood vessels. This makes them highly effective for rapid volume expansion. **Analysis of Incorrect Options:** * **Normal Saline (0.9% NaCl):** An isotonic **crystalloid**. It contains small electrolytes that freely pass through capillary pores into the interstitial space. * **Ringer’s Lactate (RL):** A balanced salt **crystalloid**. Like saline, it distributes throughout the entire extracellular fluid (ECF) compartment. * **Dextrose 5% (D5W):** A hypotonic **crystalloid**. Once the glucose is metabolized, it leaves behind free water which distributes across all body compartments (Intracellular + Extracellular). **High-Yield Clinical Pearls for NEET-PG:** * **Volume Expansion Ratio:** For every 100 mL of blood lost, you need ~300 mL of crystalloid (3:1 ratio) but only ~100 mL of colloid (1:1 ratio) to maintain hemodynamics. * **Synthetic Colloids:** Include Hydroxyethyl Starches (HES), Gelatins, and Dextrans. Note that HES is now restricted due to risks of acute kidney injury (AKI). * **Albumin Concentrations:** Available as 5% (iso-oncotic) and 25% (hyper-oncotic). * **Key Concept:** Crystalloids are the first-line choice for fluid resuscitation; colloids are reserved for specific indications like severe hypoalbuminemia or when crystalloids fail to achieve volume targets.

Q: Which intravenous anesthetic agent produces a cocaine-like effect on the cardiovascular system?

Ketamine. ### Explanation **Correct Answer: C. Ketamine** Ketamine is a unique intravenous anesthetic that acts as a **sympathomimetic** agent. Its "cocaine-like" effect on the cardiovascular system is due to two primary mechanisms: 1. **Direct Stimulation:** It stimulates the central sympathetic nervous system. 2. **Inhibition of Reuptake:** Like cocaine, it inhibits the neuronal reuptake of catecholamines (norepinephrine) into postganglionic sympathetic nerve endings. This results in an **increase in heart rate, arterial blood pressure, and cardiac output**, making it the induction agent of choice for patients in hypovolemic shock. --- ### Why the other options are incorrect: * **A. Thiopentone:** A barbiturate that causes dose-dependent myocardial depression and peripheral vasodilation (venodilation), leading to a **decrease in blood pressure**. * **B. Propofol:** Known for causing the most significant **hypotension** among induction agents due to profound vasodilation and decreased myocardial contractility. It also blunts the baroreceptor reflex. * **D. Etomidate:** Renowned for its **cardiovascular stability**. It causes minimal changes in heart rate and blood pressure, making it ideal for patients with cardiac disease, but it does not produce a sympathomimetic "cocaine-like" surge. --- ### High-Yield Clinical Pearls for NEET-PG: * **Dissociative Anesthesia:** Ketamine produces a state where the patient appears awake (eyes open) but is unconscious and feels no pain. * **Bronchodilation:** Ketamine is the induction agent of choice for **Asthmatic patients**. * **Contraindications:** Avoid Ketamine in patients with **Ischemic Heart Disease (IHD)** or Hypertension (due to increased myocardial oxygen demand) and in cases of **increased Intracranial Pressure (ICP)**. * **Emergence Delirium:** A common side effect of Ketamine, which can be pre-treated with Benzodiazepines (e.g., Midazolam).

Q: Which of the following drugs has caused hyperkalemia leading to cardiac arrest in patients with neurological disorders?

Succinylcholine. **Explanation:** **Succinylcholine (Suxamethonium)** is a depolarizing neuromuscular blocker that acts as an agonist at the nicotinic acetylcholine receptors (nAChR) at the neuromuscular junction. **Why Succinylcholine is the correct answer:** In normal individuals, succinylcholine causes a transient rise in serum potassium (~0.5 mEq/L). However, in patients with **neurological disorders** (e.g., stroke, spinal cord injury, burns, or muscular dystrophy), there is an **upregulation of extrajunctional acetylcholine receptors**. When succinylcholine binds to these widespread receptors, it causes massive, prolonged depolarization, leading to an efflux of potassium from the cells into the extracellular fluid. This **exaggerated hyperkalemia** can lead to fatal cardiac arrhythmias and cardiac arrest. **Why the other options are incorrect:** * **Baclofen:** A GABA-B receptor agonist used as a muscle relaxant for spasticity; it does not act on nAChR and does not cause hyperkalemia. * **Dantrolene:** Acts intracellularly by inhibiting the ryanodine receptor (RyR1) to prevent calcium release from the sarcoplasmic reticulum. It is the treatment of choice for Malignant Hyperthermia and does not cause hyperkalemia. * **Tubocurarine:** A non-depolarizing neuromuscular blocker. These drugs are competitive antagonists and do not cause depolarization; therefore, they do not trigger potassium release and are generally safe in patients at risk for hyperkalemia. **NEET-PG High-Yield Pearls:** * **Avoid Succinylcholine in:** Burns (>24 hours), massive trauma, prolonged immobilization, and upper/lower motor neuron lesions. * **Drug of choice for RSI:** Succinylcholine (due to rapid onset and short duration), but **Rocuronium** is the preferred alternative if hyperkalemia is a concern. * **Malignant Hyperthermia:** Succinylcholine is a known trigger.

Q: A patient is posted for surgery 6 weeks post-burn. What is a likely cause of increased intraoperative requirements?

Succinylcholine. ### Explanation **Correct Answer: A. Succinylcholine** The correct answer is **Succinylcholine**, though the question phrasing "increased requirements" refers to the **increased risk/complication** associated with its use in the post-burn period. **Underlying Medical Concept:** In the post-burn state (typically from 24 hours up to 1–2 years post-injury), there is a massive **upregulation of extrajunctional acetylcholine receptors (nAChR)** across the muscle membrane. When Succinylcholine (a depolarizing neuromuscular blocker) is administered, these receptors open simultaneously, causing an efflux of potassium from the cells. In burn patients, this leads to **exaggerated hyperkalemia**, which can result in fatal cardiac arrhythmias or cardiac arrest. Therefore, Succinylcholine is strictly contraindicated in this period. **Why other options are incorrect:** * **B. Anesthetic negligence:** While complications can arise from errors, the physiological response to Succinylcholine in a burn patient is a known pharmacological phenomenon, not a result of negligence. * **C. Post-burn state:** While the "post-burn state" is the *reason* for the physiological change, it is not the "requirement" or the drug causing the specific intraoperative crisis mentioned in the context of anesthesia pharmacology. **High-Yield Clinical Pearls for NEET-PG:** * **The "Safe Window":** Succinylcholine is generally considered safe within the first **24 hours** post-burn. The risk of hyperkalemia peaks between **1 to 6 months** but can persist for over a year. * **Resistance to Non-depolarizers:** Conversely, burn patients show **resistance** to non-depolarizing muscle relaxants (e.g., Vecuronium, Rocuronium) due to the same receptor upregulation, requiring **increased doses** of these specific drugs. * **Potassium Shift:** A normal dose of Succinylcholine usually raises serum $K^+$ by **0.5 mEq/L**; in burn patients, this rise can exceed **5–10 mEq/L**.

Q: Which of the following drugs is known to cause severe pain on injection?

Thiopentone. **Explanation** The correct answer is **Thiopentone (Option A)**. **Why Thiopentone is correct:** Thiopentone sodium is an ultra-short-acting barbiturate used for the induction of anesthesia. It is highly alkaline, with a **pH of approximately 10.5**. Due to this high alkalinity, it is extremely irritating to the vascular endothelium. If injected into a small vein or accidentally administered **intra-arterially**, it causes intense pain, severe vasoconstriction (vasospasm), and can lead to tissue necrosis or gangrene. To minimize pain and the risk of thrombophlebitis, it is typically administered in a dilute concentration (2.5%). **Why the other options are incorrect:** * **Pethidine (Option B):** While pethidine can cause local histamine release leading to redness or itching along the vein, it is not primarily known for "severe pain on injection" in the same clinical context as alkaline barbiturates. * **Phenobarbitone (Option C):** Although also a barbiturate, it is a long-acting sedative/anticonvulsant. While alkaline, it is not the classic "high-yield" answer associated with induction-related injection pain in anesthesiology exams compared to Thiopentone or Propofol. * **Ketamine (Option D):** Ketamine is generally non-irritating to the veins and is often used in pediatric or emergency settings because it can be given intramuscularly without causing significant tissue damage or severe pain. **Clinical Pearls for NEET-PG:** * **Propofol** is the other common induction agent notorious for pain on injection (mitigated by using larger veins or pre-treating with Lidocaine). * **Management of Intra-arterial Thiopentone:** If accidental intra-arterial injection occurs, the needle should be left in place to administer vasodilators (e.g., **Papaverine** or **Phentolamine**) and a sympathetic block (e.g., Stellate ganglion block) to prevent gangrene. * **Etomidate** also causes significant pain on injection and a high incidence of myoclonus.

Question 1

Which of the following statements regarding Non-Depolarizing Muscle Relaxants is FALSE?

Accepted Answer

Non-depolarizing agents trigger malignant hyperthermia.

Answer

Vecuronium can be used safely in patients with renal failure.

Answer

Aminoglycosides can worsen neuromuscular blockade in patients with renal failure.

Answer

Pancuronium possesses vagolytic effects.

Question 2

Which of the following statements regarding neuromuscular blockers are true?

Accepted Answer

Statements 1, 2, 3, 4, and 5 are true.

Answer

Statements 1, 2, and 3 are true, and statements 4 and 5 are false.

Answer

Statements 1, 2, 3, and 5 are true, and statement 4 is false.

Answer

Statements 1 and 2 are true, and statements 3, 4, and 5 are false.

Question 3

The rate at which the alveolar concentration of an anesthetic approaches inspired concentration is a function of all except?

Accepted Answer

Saturated vapor pressure

Answer

Alveolar ventilation

Answer

Water solubility of agent

Answer

Cardiac output

Question 4

Polygelin content is found in which of the following fluids?

Accepted Answer

Haemaccel

Answer

Gelofuscine

Answer

Hartmann's solution

Answer

Hetastarch

Question 5

Which of the following is the fastest acting anesthetic agent?

Accepted Answer

Sevoflurane

Answer

Desflurane

Answer

Isoflurane

Answer

None of the above

Question 6

Which of the following solutions is a colloid?

Accepted Answer

Albumin

Answer

Normal saline

Answer

Ringer lactate

Answer

Dextrose 5%

Question 7

Which intravenous anesthetic agent produces a cocaine-like effect on the cardiovascular system?

Accepted Answer

Ketamine

Answer

Thiopentone

Answer

Propofol

Answer

Etomidate

Question 8

Which of the following drugs has caused hyperkalemia leading to cardiac arrest in patients with neurological disorders?

Accepted Answer

Succinylcholine

Answer

Baclofen

Answer

Dantrolene

Answer

Tubocurarine

Question 9

A patient is posted for surgery 6 weeks post-burn. What is a likely cause of increased intraoperative requirements?

Accepted Answer

Succinylcholine

Answer

Anesthetic negligence

Answer

Post-burn state

Answer

None of the above

Question 10

Which of the following drugs is known to cause severe pain on injection?

Accepted Answer

Thiopentone

Answer

Pethidine

Answer

Phenobarbitone

Answer

Ketamine

General Anesthesia — MCQs

General Anesthesia — MCQs

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