General Anesthesia Practice Questions

Q: All of the following are causes of increased heart rate except:

Halothane. **Explanation:** The correct answer is **Halothane** because, unlike modern volatile anesthetics, it does not typically cause an increase in heart rate; in fact, it often causes **bradycardia** or maintains a stable heart rate. **1. Why Halothane is the correct answer:** Halothane increases vagal (parasympathetic) tone and inhibits the baroreceptor reflex. This leads to a decrease in heart rate (bradycardia). Furthermore, Halothane is unique because it **sensitizes the myocardium to catecholamines**, which increases the risk of arrhythmias (especially ventricular) if epinephrine is administered concurrently, but the baseline effect is not tachycardia. **2. Why the other options are incorrect:** * **Isoflurane:** It is a potent vasodilator that causes a decrease in systemic vascular resistance (SVR). This triggers a **reflex tachycardia** via the baroreceptor mechanism. * **Desflurane:** Known for causing a transient but significant increase in heart rate and blood pressure, especially during a rapid increase in inspired concentration, due to **sympathetic nervous system stimulation**. * **Sevoflurane:** While it has the least effect on heart rate at low concentrations (making it ideal for pediatric induction), it can still cause increases in heart rate at deeper levels of anesthesia (concentrations >1.5 MAC). **Clinical Pearls for NEET-PG:** * **"Halothane Hepatitis":** A rare but classic boards-style complication. * **Arrhythmogenic potential:** Halothane + Adrenaline = High risk of PVCs/Ventricular Tachycardia. * **Pungency:** Isoflurane and Desflurane are pungent (irritate airways), whereas **Halothane and Sevoflurane are non-pungent**, making them suitable for inhalation induction. * **Speed of Induction:** Desflurane (lowest blood-gas solubility) is the fastest; Halothane is the slowest among the options.

Q: Which of the following has the maximum analgesic action?

Ketamine. **Explanation:** **Ketamine** is the correct answer because it is a unique intravenous anesthetic agent that provides **profound analgesia** even at sub-anesthetic doses. Its primary mechanism of action is the non-competitive antagonism of **NMDA (N-methyl-D-aspartate) receptors** in the brain and spinal cord. Unlike most other induction agents, ketamine produces "dissociative anesthesia," characterized by a sensory-dissociative state where the patient appears awake but is unresponsive to pain. **Analysis of Incorrect Options:** * **Propofol:** While it is the most commonly used induction agent due to its rapid onset and recovery, it has **no analgesic properties**. In fact, it may occasionally cause hyperalgesia (increased sensitivity to pain) at low doses. * **Thiopentone Sodium:** This barbiturate is a potent hypnotic but is notorious for being **anti-analgesic**. It lowers the pain threshold, meaning patients may react more intensely to painful stimuli under light levels of thiopentone anesthesia. * **Catecholamines:** These are endogenous signaling molecules (like Adrenaline/Noradrenaline) or exogenous vasopressors. While they affect hemodynamics and the sympathetic nervous system, they are not classified as anesthetic or primary analgesic agents. **High-Yield Clinical Pearls for NEET-PG:** * **Ketamine** is the drug of choice for induction in **hypovolemic shock** (due to sympathetic stimulation) and **bronchial asthma** (due to bronchodilation). * It is the only induction agent that **increases** intracranial pressure (ICP), intraocular pressure (IOP), and heart rate/blood pressure. * **Emergence delirium** is a common side effect of ketamine, which can be mitigated by co-administering benzodiazepines like Midazolam. * **Thiopentone** is the drug of choice for rapid sequence induction in patients with increased ICP (neuroprotection).

Q: Which of the following barbiturates is used for induction of anesthesia?

Thiopentone. **Explanation:** **1. Why Thiopentone is Correct:** Thiopentone (Thiopental sodium) is an ultra-short-acting barbiturate that has been the "gold standard" for the induction of anesthesia for decades. Its rapid onset of action (within 30–45 seconds) is due to its high lipid solubility, allowing it to cross the blood-brain barrier almost instantly. The rapid recovery from its anesthetic effect is not due to metabolism, but rather **redistribution** from the brain to less vascular tissues like skeletal muscle and fat. **2. Why the Other Options are Incorrect:** * **Naloxone (Option B):** This is a competitive **opioid antagonist** used specifically to reverse opioid overdose and respiratory depression. It has no anesthetic properties. * **Naltrexone (Option C):** Similar to Naloxone, this is a long-acting opioid antagonist primarily used in the management of alcohol and opioid dependence. * **Phenobarbitone (Option D):** While this is a barbiturate, it is a **long-acting** agent. Due to its slow onset and prolonged duration, it is used as an antiepileptic (especially in neonatal seizures) rather than for the induction of anesthesia. **3. High-Yield Clinical Pearls for NEET-PG:** * **Mechanism of Action:** Facilitates GABA-A receptors by increasing the **duration** of chloride channel opening. * **Contraindication:** Absolutely contraindicated in **Porphyria** (induces ALA synthetase). * **Side Effects:** Causes dose-dependent respiratory depression and hypotension. It is a potent **venodilator**. * **Protective Effect:** It decreases Cerebral Blood Flow (CBF) and Cerebral Metabolic Rate of Oxygen ($CMRO_2$), making it **neuroprotective**. * **Accidental Intra-arterial Injection:** Can cause severe spasm and gangrene. Treatment includes injecting vasodilators like **Papaverine** or performing a **Stellate ganglion block**.

Q: Presence of trifluoroacetic acid (TFA) in urine indicates that the volatile anesthetic agent used was:

Halothane. **Explanation:** The correct answer is **Halothane**. **1. Why Halothane is correct:** Halothane undergoes significant hepatic metabolism (approximately 20%). It is metabolized by the cytochrome P450 system (specifically CYP2E1) via oxidative pathways. The primary end-product of this oxidative metabolism is **Trifluoroacetic acid (TFA)**, which is excreted in the urine. TFA is clinically significant because it can covalently bind to hepatic proteins, forming "TFA-protein adducts." In susceptible individuals, these adducts act as haptens, triggering an immune response that leads to **Halothane Hepatitis**. **2. Why other options are incorrect:** * **Methoxyflurane:** Its metabolism primarily releases **inorganic fluoride ions** and oxalic acid. High levels of fluoride ions are associated with dose-dependent nephrotoxicity (high-output renal failure). * **Trichloroethylene:** It is metabolized into **Trichloroethanol** and **Trichloroacetic acid**. It is no longer used in modern anesthesia due to its potential to react with soda lime to form neurotoxic dichloroacetylene. **3. High-Yield Clinical Pearls for NEET-PG:** * **Metabolism Ranking:** Halothane (20%) > Sevoflurane (2-5%) > Isoflurane (0.2%) > Desflurane (0.02%). * **Other TFA producers:** Isoflurane and Desflurane also produce TFA, but in much smaller, negligible quantities compared to Halothane. * **Halothane Shivering:** Halothane is known to cause post-operative shivering due to its effect on the hypothalamus. * **Catecholamine Sensitivity:** Halothane sensitizes the myocardium to catecholamines, increasing the risk of arrhythmias if epinephrine is administered concurrently.

Q: Which of the following muscle relaxants can cause pain at the IV injection site?

Rocuronium. **Explanation:** **Rocuronium** is a non-depolarizing neuromuscular blocking agent (NMBA) frequently associated with **pain on injection**, occurring in up to 50–80% of patients when administered in an awake state. The underlying mechanism is attributed to the **low pH (acidic nature)** of the solution (pH ~4) and the release of local mediators like kinins, which irritate the venous nociceptors. This is a high-yield clinical point because the pain can cause "withdrawal movements" of the limb, which may be mistaken for inadequate anesthesia depth. **Analysis of Options:** * **Succinylcholine (Option A):** While it causes postoperative **myalgia** (muscle soreness) due to fasciculations, it does not typically cause acute pain at the IV site during the injection itself. * **Vecuronium (Option B):** It is nearly pH-neutral when reconstituted and is not associated with significant injection site pain or histamine release. * **Pancuronium (Option D):** A long-acting NMBA that is generally painless on injection. Its primary side effect is tachycardia due to its vagolytic action. **High-Yield Clinical Pearls for NEET-PG:** * **Mitigation:** Injection pain from Rocuronium can be reduced by pre-administering IV Lidocaine or using a larger vein. * **Rocuronium** has the fastest onset among non-depolarizing NMBAs, making it the drug of choice for **Rapid Sequence Induction (RSI)** when Succinylcholine is contraindicated. * **Sugammadex** is the specific reversal agent for Rocuronium and Vecuronium. * **Histamine Release:** Unlike Rocuronium, older agents like **Atracurium** and **Mivacurium** are more likely to cause systemic histamine release (flushing, hypotension, bronchospasm).

Q: Which of the following is NOT a true statement regarding sevoflurane?

It can be used safely in malignant hyperthermia.. **Explanation:** **1. Why Option C is the correct answer (The "NOT" statement):** Sevoflurane, like all potent volatile halogenated inhalational anesthetics (e.g., Halothane, Isoflurane, Desflurane) and the depolarizing muscle relaxant Succinylcholine, is a **known trigger for Malignant Hyperthermia (MH)**. In genetically susceptible individuals with a mutation in the ryanodine receptor (RYR1), sevoflurane causes an uncontrolled release of calcium from the sarcoplasmic reticulum, leading to a hypermetabolic state. Therefore, it is **absolutely contraindicated** in patients with a history of MH. **2. Analysis of Incorrect Options:** * **Option A:** Sevoflurane is the **agent of choice for pediatric induction** because it has a non-pungent odor, is non-irritating to the airway (low risk of laryngospasm), and has a low blood-gas partition coefficient (0.65), allowing for rapid induction and recovery. * **Option B:** When sevoflurane reacts with dry carbon dioxide absorbents (specifically those containing Potassium or Sodium Hydroxide like Sodalime), it undergoes degradation to form **Compound A** (fluoromethyl-2,2-difluoro-1-(trifluoromethyl) vinyl ether), which is nephrotoxic in rat models. * **Option D:** While sevoflurane is generally cardiovascularly stable, it can cause a dose-dependent decrease in blood pressure and a **reflex increase in heart rate (tachycardia)**, especially at higher concentrations (>1.5 MAC). **High-Yield NEET-PG Pearls:** * **Blood-Gas Partition Coefficient:** 0.65 (Fast induction/emergence). * **MAC (Minimum Alveolar Concentration):** ~2% in oxygen. * **Metabolism:** Approximately 5-8% (higher than Isoflurane/Desflurane), releasing inorganic fluoride ions. * **Clinical Caution:** To prevent Compound A accumulation, it is recommended to maintain a fresh gas flow of at least **1-2 Liters/min**.

Question 1

In which stage of anesthesia does the patient become hyperactive?

Accepted Answer

Stage 2

Answer

Stage 1

Answer

Stage 3

Answer

Stage 4

Question 2

Regarding gantacurium, which of the following statements is true?

Accepted Answer

It has an oxime chloro fumarate group.

Answer

It is a depolarizing neuromuscular blocker.

Answer

L-cysteine is the reversal agent.

Answer

It has a longer duration of action than succinylcholine.

Question 3

All of the following are causes of increased heart rate except:

Accepted Answer

Halothane

Answer

Isoflurane

Answer

Sevoflurane

Answer

Desflurane

Question 4

Which of the following has the maximum analgesic action?

Accepted Answer

Ketamine

Answer

Catecholamine

Answer

Propofol

Answer

Thiopentone

Question 5

Which of the following barbiturates is used for induction of anesthesia?

Accepted Answer

Thiopentone

Answer

Naloxone

Answer

Naltrexone

Answer

Phenobarbitone

Question 6

Presence of trifluoroacetic acid (TFA) in urine indicates that the volatile anesthetic agent used was:

Accepted Answer

Halothane

Answer

Methoxyflurane

Answer

Trichloroethylene

Answer

None of the above

Question 7

What is the lowest concentration of an anesthetic agent in the alveoli that is needed to produce immobility in response to a painful stimulus in 50% of individuals?

Accepted Answer

Minimum alveolar concentration

Answer

Minimal analgesic concentration

Answer

Minimal anesthetic concentration

Answer

Maximum alveolar concentration

Question 8

Which of the following muscle relaxants can cause pain at the IV injection site?

Accepted Answer

Rocuronium

Answer

Succinylcholine

Answer

Vecuronium

Answer

Pancuronium

Question 9

During general anesthesia, shivering is abolished by suppression of which part of the brain?

Accepted Answer

Hypothalamus

Answer

Thalamus

Answer

Cerebral cortex

Answer

Medulla

Question 10

Which of the following is NOT a true statement regarding sevoflurane?

Accepted Answer

It can be used safely in malignant hyperthermia.

Answer

It is an ideal agent for pediatric anesthesia.

Answer

It can interact with sodalime and form Compound A.

Answer

It causes tachycardia.

General Anesthesia — MCQs

General Anesthesia — MCQs

On this page

Practice by Chapter

Want unlimited practice?