General Anesthesia Practice Questions

Q: Which of the following is NOT true about Rocuronium bromide?

It is most preferred in hepatic and renal failure.. **Explanation:** **Rocuronium bromide** is an amino-steroid, non-depolarizing neuromuscular blocking agent (NMBA) with an intermediate duration of action. **Why Option D is the Correct Answer (The False Statement):** Rocuronium is primarily eliminated via **hepatic metabolism and biliary excretion** (approx. 70%), with the remainder excreted by the kidneys. In patients with hepatic or renal failure, its clearance is significantly reduced, leading to a prolonged duration of action and unpredictable recovery. For these patients, **Cisatracurium** is the drug of choice because it undergoes **Hofmann elimination** (organ-independent degradation), making it safer in organ failure. **Analysis of Other Options:** * **Option A:** It is indeed one of the most commonly used NMBAs due to its rapid onset and stable cardiovascular profile. * **Option B:** At a dose of 0.9–1.2 mg/kg, Rocuronium provides excellent intubating conditions in <60 seconds, making it the best non-depolarizing alternative to Succinylcholine for **Rapid Sequence Induction (RSI)**. * **Option C:** **Sugammadex** is a selective relaxant binding agent designed specifically to encapsulate and rapidly reverse Rocuronium (and Vecuronium), even during deep blockade. **High-Yield Clinical Pearls for NEET-PG:** * **Onset of Action:** Fastest among non-depolarizing NMBAs (60–90 seconds). * **Storage:** Should be stored in a refrigerator (2–8°C) to maintain potency. * **RSI Dose:** 1.2 mg/kg (double the standard intubating dose of 0.6 mg/kg). * **Side Effects:** It is relatively cardiovascular stable but can rarely cause mild tachycardia. Unlike older agents, it has minimal histamine release.

Q: Ketamine is safe in which of the following conditions?

Severe shock. **Explanation:** **Ketamine** is a unique dissociative anesthetic that acts primarily as an **NMDA receptor antagonist**. **Why "Severe Shock" is the Correct Answer:** Ketamine is the induction agent of choice in hemodynamically unstable patients (severe shock, trauma, or hypovolemia). Unlike most induction agents (like Propofol or Thiopental) which cause myocardial depression and vasodilation, Ketamine stimulates the **sympathetic nervous system**. It causes an indirect release of catecholamines, leading to an **increase in heart rate, blood pressure, and cardiac output**, which helps maintain perfusion in shock states. **Why Other Options are Incorrect:** * **Raised Intracranial Pressure (ICT):** Ketamine is traditionally contraindicated in head injuries because it increases cerebral blood flow (CBF), cerebral metabolic rate ($CMRO_2$), and ICP, potentially worsening brain herniation. * **Open Eye Injury:** Ketamine increases **Intraocular Pressure (IOP)** due to its effect on extraocular muscle tone and sympathetic stimulation. This can lead to the extrusion of intraocular contents in an open-globe injury. * **Ischemic Heart Disease (IHD):** Because Ketamine increases myocardial oxygen demand (due to tachycardia and hypertension), it can precipitate myocardial ischemia or infarction in patients with pre-existing coronary artery disease. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Dissociative anesthesia (eyes remain open with a slow nystagmic gaze). * **Airway:** It preserves airway reflexes and is a potent **bronchodilator** (drug of choice for induction in status asthmaticus). * **Secretions:** It causes **hypersalivation**; hence, premedication with Glycopyrrolate is often required. * **Emergence:** Associated with **emergence delirium/hallucinations**, which can be prevented by co-administering Benzodiazepines (e.g., Midazolam).

Q: All are true about cisatracurium except?

It also causes histamine release like atracurium. **Explanation:** Cisatracurium is a benzylisoquinolinium neuromuscular blocking agent (NMBA) and is one of the ten isomers of atracurium. **Why Option C is the correct answer (The False Statement):** Unlike its parent compound atracurium, **cisatracurium does not cause histamine release**, even at doses up to 8 times its $ED_{95}$. Atracurium is notorious for triggering mast cell degranulation, leading to skin flushing, hypotension, and bronchospasm. The absence of histamine release makes cisatracurium hemodynamically stable and a preferred choice in patients with reactive airway disease or cardiovascular instability. **Analysis of Incorrect Options:** * **Option A:** Cisatracurium is indeed the isolated **1R-cis 1’R-cis isomer** of atracurium. By isolating this specific isomer, the side effects associated with the other isomers are eliminated. * **Option B:** It is approximately **3 to 4 times more potent** than atracurium. The $ED_{95}$ of cisatracurium is ~0.05 mg/kg, compared to ~0.2 mg/kg for atracurium. * **Option D:** Like atracurium, it undergoes **Hofmann elimination** (spontaneous degradation at physiological pH and temperature). This makes its clearance independent of renal or hepatic function. **High-Yield Clinical Pearls for NEET-PG:** 1. **Organ-Independent Elimination:** Cisatracurium is the "drug of choice" for muscle relaxation in patients with **renal or hepatic failure**. 2. **Laudanosine Toxicity:** Hofmann elimination produces a metabolite called laudanosine (a CNS stimulant). However, because cisatracurium is more potent, less drug is used, resulting in significantly **lower levels of laudanosine** compared to atracurium, reducing the risk of seizures. 3. **Temperature/pH Sensitivity:** Since it relies on Hofmann elimination, its duration of action is prolonged in patients with **hypothermia or acidosis**.

Q: A 70 kg patient needs to be started on nitroglycerine (NTG) infusion. A 5 ml ampoule contains 5 mg/ml NTG. One ampoule is added to normal saline to make a total of 500 ml solution. Calculate the infusion rate if NTG is required at a rate of 10 mcg/min. (1 micro drip = 60 drops/ml)

12 drops/min. ### Explanation This question tests your ability to perform clinical drug calculations, a high-yield skill for NEET-PG. To solve this, follow a step-by-step approach: **1. Calculate the Total Amount of Drug:** * Ampoule volume = 5 ml; Concentration = 5 mg/ml. * Total NTG = 5 ml × 5 mg/ml = **25 mg**. **2. Determine the Concentration of the Infusion:** * Total solution volume = 500 ml. * Concentration = 25 mg / 500 ml = 0.05 mg/ml. * Convert to micrograms: 0.05 mg × 1000 = **50 mcg/ml**. **3. Calculate the Infusion Rate in ml/min:** * Required dose = 10 mcg/min. * Rate (ml/min) = Dose required / Concentration = 10 mcg/min ÷ 50 mcg/ml = **0.2 ml/min**. **4. Convert to Drops/min:** * Standard micro drip set = 60 drops/ml. * Infusion rate = 0.2 ml/min × 60 drops/ml = **12 drops/min**. --- ### Analysis of Options * **A (12 drops/min): Correct.** Derived from the precise calculation of concentration (50 mcg/ml) and flow rate. * **B, C, and D:** These are incorrect. They typically result from calculation errors, such as forgetting to multiply the ampoule volume by its concentration (using 5 mg total instead of 25 mg) or using a standard macro drip (15-20 drops/ml) instead of the specified micro drip. --- ### Clinical Pearls for NEET-PG * **Nitroglycerine (NTG):** A venodilator at low doses; causes arterial dilation at higher doses. * **Indication:** Acute Coronary Syndrome (ACS), Acute Decompensated Heart Failure, and Hypertensive Emergency. * **Pharmacokinetics:** NTG has a very short half-life (~1–3 minutes), necessitating continuous infusion. * **Storage Note:** NTG is adsorbed by PVC plastic; ideally, non-PVC administration sets should be used to ensure accurate delivery. * **Tachyphylaxis:** Continuous use leads to nitrate tolerance within 24 hours due to the depletion of free sulfhydryl groups.

Q: What is the most potent analgesic agent among the following?

Nitrous oxide. **Explanation:** **Nitrous oxide ($N_2O$)**, also known as "laughing gas," is a colorless, odorless gas used extensively in anesthesia. Among the options provided, it is the only agent with significant **analgesic (pain-relieving)** properties. Its analgesic effect is primarily mediated through the release of endogenous opioid peptides (endorphins) and the inhibition of NMDA receptors in the central nervous system. While $N_2O$ is a weak general anesthetic (High MAC value of 104%), it is a **potent analgesic**; even a 20% concentration can provide pain relief equivalent to a therapeutic dose of morphine. **Analysis of Incorrect Options:** * **Nitric oxide (NO):** This is a potent endogenous vasodilator and cell-signaling molecule. In clinical practice, inhaled NO is used to treat pulmonary hypertension, but it possesses no analgesic or anesthetic properties. * **Carbon dioxide ($CO_2$):** This is a metabolic byproduct. While it acts as a respiratory stimulant, it does not have analgesic properties. In fact, high levels (hypercapnia) lead to respiratory acidosis and distress. * **Oxygen ($O_2$):** Essential for life and aerobic metabolism, oxygen is used to prevent hypoxia during anesthesia but has no inherent analgesic effect. **High-Yield Clinical Pearls for NEET-PG:** * **Second Gas Effect:** $N_2O$ is rapidly absorbed, increasing the concentration of a concurrently administered volatile anesthetic (e.g., Halothane) in the alveoli. * **Diffusion Hypoxia:** Occurs during recovery if $N_2O$ is discontinued abruptly without supplemental $O_2$; $N_2O$ rushes out of the blood into the alveoli, diluting $O_2$. * **Contraindication:** $N_2O$ should be avoided in patients with **pneumothorax, intestinal obstruction, or middle ear surgery**, as it expands into closed, air-filled spaces. * **Vitamin $B_{12}$ Deficiency:** Chronic exposure can lead to megaloblastic anemia by inactivating methionine synthase.

Q: Which of the following statements regarding depolarizing muscle relaxants is FALSE?

Reversed by neostigmine. ### Explanation Depolarizing muscle relaxants (DMRs), primarily **Succinylcholine (Suxamethonium)**, act as nicotinic acetylcholine receptor (nAChR) agonists. They mimic acetylcholine, causing prolonged depolarization of the motor endplate, which leads to a **Phase I block**. **Why Option C is the Correct (False) Statement:** Neostigmine is an acetylcholinesterase inhibitor. By preventing the breakdown of acetylcholine (ACh), it increases the concentration of ACh at the neuromuscular junction. In a Phase I block, more ACh further depolarizes the membrane, which **potentiates (worsens)** the neuromuscular blockade rather than reversing it. Therefore, neostigmine does not reverse a depolarizing block; it antagonizes only non-depolarizing blocks. **Analysis of Other Options:** * **A. Cause muscle fasciculation:** Succinylcholine causes initial disorganized muscle contractions (fasciculations) before paralysis occurs because it initially stimulates the receptors. * **B. No fade:** In a Phase I block, the response to Train-of-Four (TOF) stimulation is characterized by a constant but diminished height in all four twitches. There is no progressive decline (fade) in strength. * **D. No post-tetanic facilitation:** Unlike non-depolarizing blocks, DMRs do not show an exaggerated response to a single twitch after a tetanic stimulus. **High-Yield Clinical Pearls for NEET-PG:** * **Phase II Block:** Occurs with high doses or prolonged infusion of Succinylcholine. It mimics a non-depolarizing block (shows fade and post-tetanic facilitation) and *can* be reversed by neostigmine. * **Metabolism:** Succinylcholine is metabolized by **Pseudocholinesterase** (Plasma cholinesterase). * **Key Side Effects:** Hyperkalemia (avoid in burns/trauma), Malignant Hyperthermia trigger, and post-operative myalgia. * **Dibucaine Number:** Used to test for atypical pseudocholinesterase; a low number (e.g., 20) indicates a high risk of prolonged apnea.

Q: A patient with alcoholic liver failure requires general anesthesia. Which anesthetic agent is most appropriate?

Isoflurane. **Explanation:** The primary goal in managing anesthesia for a patient with liver failure is to maintain hepatic blood flow and minimize drug-induced hepatotoxicity. **Isoflurane** is the drug of choice because it undergoes minimal hepatic metabolism (only **0.2%**). Crucially, it preserves hepatic oxygen delivery better than other agents by maintaining the hepatic artery buffer response, ensuring stable blood flow to the liver. **Analysis of Options:** * **Halothane (Incorrect):** It is the most hepatotoxic volatile anesthetic. It undergoes significant metabolism (up to 20%) and can cause "Halothane Hepatitis" via immune-mediated mechanisms or reductive metabolites. It also significantly reduces hepatic blood flow. * **Methoxyflurane (Incorrect):** It is highly metabolized (up to 50-70%) and is primarily known for its **nephrotoxicity** due to the release of inorganic fluoride ions. It is contraindicated in patients with renal or hepatic impairment. * **Ether (Incorrect):** It causes significant sympathetic stimulation, leading to vasoconstriction and reduced splanchnic/hepatic blood flow, which can worsen liver ischemia in a failing organ. **High-Yield Clinical Pearls for NEET-PG:** * **Metabolism Rule:** Remember the mnemonic **MHISE** (highest to lowest metabolism): **M**ethoxyflurane (50-70%) > **H**alothane (20%) > **I**soflurane (0.2%) > **S**evoflurane (2-3%) > **D**esflurane (0.02%). * **Desflurane** is also safe for the liver (metabolism 0.02%), but Isoflurane remains the classic textbook answer for liver failure due to its superior preservation of hepatic blood flow. * **Muscle Relaxant of Choice:** In liver failure, **Atracurium** or **Cisatracurium** are preferred as they undergo Hoffman elimination and do not depend on the liver for clearance.

Question 1

Which of the following is NOT true about Rocuronium bromide?

Accepted Answer

It is most preferred in hepatic and renal failure.

Answer

It is one of the most commonly used non-depolarizing agents.

Answer

It is a non-depolarizing agent of choice for rapid sequence induction.

Answer

Sugammadex is its specific reversal agent.

Question 2

Ketamine is safe in which of the following conditions?

Accepted Answer

Severe shock

Answer

Raised intracranial pressure (ICT)

Answer

Open eye injury

Answer

Ischemic heart disease

Question 3

All are true about cisatracurium except?

Accepted Answer

It also causes histamine release like atracurium

Answer

It is the pure cis isomer of atracurium

Answer

It is more potent than atracurium

Answer

Its metabolism is similar to atracurium

Question 4

A 70 kg patient needs to be started on nitroglycerine (NTG) infusion. A 5 ml ampoule contains 5 mg/ml NTG. One ampoule is added to normal saline to make a total of 500 ml solution. Calculate the infusion rate if NTG is required at a rate of 10 mcg/min. (1 micro drip = 60 drops/ml)

Accepted Answer

12 drops/min

Answer

14 drops/min

Answer

15 drops/min

Answer

16 drops/min

Question 5

A 21-year-old lady with a history of hypersensitivity to neostigmine is scheduled for an elective cesarean section under general anesthesia. Which muscle relaxant is the most appropriate choice for this patient?

Accepted Answer

Atracurium

Answer

Pancuronium

Answer

Rocuronium

Answer

Vecuronium

Question 6

Which of the following statements regarding propofol is NOT TRUE?

Accepted Answer

It is contraindicated in porphyria.

Answer

It is used in day care anesthesia.

Answer

Commercial preparations contain egg extract.

Answer

It does not cause airway irritation.

Question 7

What is the most potent analgesic agent among the following?

Accepted Answer

Nitrous oxide

Answer

Nitric oxide

Answer

Carbon dioxide

Answer

Oxygen

Question 8

Which of the following statements regarding depolarizing muscle relaxants is FALSE?

Accepted Answer

Reversed by neostigmine

Answer

Cause muscle fasciculation

Answer

No fade

Answer

No post tetanic facilitation

Question 9

Which of the following is not a complication of succinylcholine?

Accepted Answer

Increased blood pressure

Answer

Increased intraocular pressure

Answer

Increased intracranial pressure

Answer

Decreased heart rate

Question 10

A patient with alcoholic liver failure requires general anesthesia. Which anesthetic agent is most appropriate?

Accepted Answer

Isoflurane

Answer

Ether

Answer

Halothane

Answer

Methoxyflurane

General Anesthesia — MCQs

General Anesthesia — MCQs

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