General Anesthesia Practice Questions

Q: Which opioid can cause tachycardia?

Pethidine. **Explanation:** The correct answer is **Pethidine** (also known as Meperidine). **Why Pethidine causes Tachycardia:** Most opioids are associated with dose-dependent bradycardia due to central stimulation of the vagus nerve. Pethidine is the notable exception. Structurally, Pethidine is related to **Atropine**. It possesses intrinsic **antimuscarinic (atropine-like) activity**, which leads to an increase in heart rate (tachycardia) and occasionally mydriasis (pupillary dilation), rather than the classic opioid-induced miosis. **Analysis of Incorrect Options:** * **Fentanyl & Remifentanil:** These are potent synthetic phenylpiperidine derivatives. They typically cause significant **bradycardia** by increasing vagal tone and decreasing sympathetic outflow. * **Morphine:** Morphine generally causes **bradycardia**. Additionally, it triggers histamine release, which can lead to peripheral vasodilation and hypotension; while a reflex tachycardia *could* theoretically occur due to hypotension, the primary direct effect remains a reduction in heart rate. **High-Yield Clinical Pearls for NEET-PG:** 1. **Miosis Exception:** Pethidine is the only opioid that does not cause significant miosis (pinpoint pupils) due to its anticholinergic effect. 2. **Metabolite Toxicity:** Pethidine is metabolized to **norpethidine**, which is a CNS stimulant. Accumulation (especially in renal failure) can cause **seizures**. 3. **Shivering:** Pethidine is the drug of choice for treating **post-operative shivering** (via stimulation of κ-receptors). 4. **Interaction:** It is strictly contraindicated with **MAO Inhibitors**, as it can precipitate a life-threatening serotonin syndrome or hyperpyrexic coma.

Q: Which of the following is NOT an intravenous anesthetic?

Desflurane. **Explanation:** The correct answer is **D. Desflurane**. **1. Why Desflurane is the correct answer:** Desflurane is a **volatile inhalation anesthetic**, not an intravenous (IV) agent. It is a halogenated methyl ethyl ether that exists as a liquid at room temperature but is delivered as a gas via a specialized heated vaporizer due to its high vapor pressure and low boiling point (23.5°C). It is primarily used for the maintenance of general anesthesia. **2. Why the other options are incorrect:** * **Propofol (A):** The most commonly used IV induction agent. It is a substituted isopropylphenol known for its rapid onset, short duration, and "milk of amnesia" appearance (lipid emulsion). * **Opioids (B):** Agents like Fentanyl, Sufentanil, and Remifentanil are classified as IV anesthetics/analgesics. They are frequently used as part of "Balanced Anesthesia" or "Total Intravenous Anesthesia" (TIVA) to provide intense analgesia and supplement induction. * **Ketamine (C):** A phencyclidine derivative used as an IV anesthetic. It produces "dissociative anesthesia" and is unique for providing both anesthesia and potent analgesia while maintaining airway reflexes. **3. Clinical Pearls for NEET-PG:** * **Desflurane:** Has the lowest blood-gas partition coefficient (0.42) among volatile agents, leading to the fastest recovery ("fastest out"). However, it is a known airway irritant and can cause coughing or laryngospasm during induction. * **Propofol:** Drug of choice for TIVA and day-care surgery; possesses anti-emetic properties. * **Ketamine:** Drug of choice for induction in patients with bronchial asthma (bronchodilator) and hypovolemic shock (sympathomimetic). * **Etomidate:** The most cardiostable IV induction agent, preferred in patients with coronary artery disease.

Q: Which of the following is not an amino steroid derivative?

Alcuronium. ### Explanation Neuromuscular blocking agents (NMBAs) are broadly classified based on their chemical structure into two main categories: **Aminosteroids** and **Benzylisoquinolines**. **1. Why Alcuronium is the Correct Answer:** Alcuronium is a semi-synthetic derivative of toxiferine, an alkaloid derived from South American curare. Chemically, it belongs to the **Benzylisoquinoline** (or more specifically, the indole alkaloid) class, not the aminosteroid group. It is a long-acting non-depolarizing muscle relaxant that is rarely used in modern practice due to its tendency to cause hypotension via histamine release and ganglion blockade. **2. Why the Other Options are Incorrect:** * **Pancuronium:** The prototype **aminosteroid**. It is long-acting and known for its vagolytic effect (causing tachycardia). * **Vecuronium:** A monoquaternary **aminosteroid** derived from pancuronium. It is intermediate-acting and lacks significant cardiovascular side effects. * **Pipecuronium:** A potent, long-acting **aminosteroid** similar to pancuronium but without the vagolytic effects. **3. High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Aminosteroids:** They usually end in **"-curonium"** (Pancuronium, Vecuronium, Rocuronium, Pipecuronium). * **Mnemonic for Benzylisoquinolines:** They usually end in **"-curium"** (Atracurium, Cisatracurium, Mivacurium) — *Exception: Alcuronium.* * **Metabolism:** Aminosteroids are primarily metabolized by the **liver** and excreted by the **kidneys**. In contrast, Atracurium and Cisatracurium undergo **Hofmann elimination** (organ-independent breakdown), making them the drugs of choice in liver or renal failure. * **Rocuronium** is the aminosteroid with the fastest onset, making it an alternative to Succinylcholine for Rapid Sequence Induction (RSI).

Q: A 40-year-old female underwent surgery. Postoperatively, she stated she was aware of preoperative events. Intraoperative awareness is evaluated by?

Bispectral imaging. **Explanation:** **1. Why Bispectral Index (BIS) is Correct:** Intraoperative awareness (accidental consciousness under general anesthesia) occurs when the depth of anesthesia is inadequate. The **Bispectral Index (BIS)** is a processed EEG parameter used to monitor the **depth of anesthesia** and the hypnotic effect of drugs on the brain. It provides a dimensionless score from 0 to 100: * **100:** Fully awake. * **40–60:** Recommended range for general anesthesia (low risk of awareness). * **0:** Isoelectric EEG (brain inactivity). By monitoring cortical activity, BIS helps clinicians titrate anesthetic doses to prevent awareness while avoiding over-sedation. **2. Why Other Options are Incorrect:** * **Pulse Oximetry (A):** Measures oxygen saturation ($SpO_2$) in arterial blood. It monitors respiratory function and oxygenation, not neurological depth. * **Color Doppler (B):** An ultrasound technique used to visualize blood flow through vessels and heart chambers. It has no role in monitoring consciousness. * **End-Tidal $CO_2$ (ETCO2) (D):** Measures the concentration of carbon dioxide at the end of expiration. It is the gold standard for confirming endotracheal tube placement and monitoring ventilation/perfusion, but it does not reflect the patient's level of awareness. **Clinical Pearls for NEET-PG:** * **Isolated Forearm Technique:** The "Gold Standard" for detecting intraoperative awareness (though rarely used clinically). * **Incidence:** Awareness is most common in **Trauma surgery, Emergency Cesarean sections, and Cardiac surgery** due to lighter anesthesia levels. * **Other Depth Monitors:** Entropy, Patient State Index (PSI), and Auditory Evoked Potentials (AEP). * **Risk Factors:** Chronic alcohol/opioid use, difficult airway, and use of neuromuscular blockers (which mask movement).

Q: Oxygen is administered during anesthesia to prevent which of the following?

Hypoxia. **Explanation:** The primary objective of administering supplemental oxygen during anesthesia is to prevent **Hypoxia** (low oxygen levels in the tissues). During general anesthesia, several factors compromise oxygenation: 1. **Hypoventilation:** Anesthetic agents and neuromuscular blockers depress the respiratory drive and weaken respiratory muscles. 2. **Reduced Functional Residual Capacity (FRC):** Induction of anesthesia causes a decrease in FRC, leading to atelectasis and ventilation-perfusion (V/Q) mismatch. 3. **Apnea during Intubation:** Pre-oxygenation (denitrogenation) is performed specifically to create an oxygen reservoir in the lungs to prevent hypoxia during the period of apnea required for securing the airway. **Analysis of Incorrect Options:** * **A. Pain:** Pain is managed using analgesics (e.g., opioids, NSAIDs) or regional blocks, not oxygen. * **C. Hypercapnia:** This refers to elevated $CO_2$ levels. While oxygenation is vital, hypercapnia is prevented by maintaining adequate **minute ventilation** (tidal volume × respiratory rate) via manual or mechanical ventilation. * **D. Hypotension:** Low blood pressure is typically managed with intravenous fluids, vasopressors, or by adjusting the depth of anesthesia. **High-Yield Clinical Pearls for NEET-PG:** * **Pre-oxygenation:** Involves breathing 100% $O_2$ for 3 minutes (or 8 vital capacity breaths) to replace nitrogen in the FRC, increasing the "safety period" of apnea. * **Diffusion Hypoxia (Fink Effect):** Occurs at the end of nitrous oxide ($N_2O$) administration. Rapid diffusion of $N_2O$ from the blood into the alveoli dilutes the $O_2$ concentration. This is prevented by administering 100% $O_2$ for 5–10 minutes after stopping $N_2O$. * **Color Coding:** In India/International standards, Oxygen cylinders are **Black with a White shoulder**.

Q: Which of the following is true regarding Remifentanil?

All of these. **Explanation:** Remifentanil is a unique, ultra-short-acting synthetic $\mu$-opioid receptor agonist. Its pharmacological profile makes it a high-yield topic for NEET-PG. * **Metabolism (Option B):** Unlike other opioids metabolized by the liver, Remifentanil contains an **ester linkage**. This allows it to be rapidly broken down by **non-specific plasma and tissue esterases**. This metabolism is independent of renal or hepatic function, leading to a predictable, ultra-short duration of action. * **Clinical Use (Option A):** Because of its rapid onset and offset (context-sensitive half-life of ~3–4 minutes), it is ideal for **short, painful procedures** (e.g., retrobulbar blocks, brief endoscopies) and for providing intense intraoperative analgesia via continuous infusion without the risk of drug accumulation. * **Potency (Option C):** Remifentanil is roughly **equipotent to Fentanyl** (both are approximately 100 times more potent than morphine). **Why "All of these" is correct:** Remifentanil satisfies all three criteria: it is highly potent (equipotent to fentanyl), uniquely metabolized by esterases, and specifically indicated for short procedures where rapid recovery is desired. **High-Yield Clinical Pearls for NEET-PG:** 1. **Context-Sensitive Half-life:** It is the only opioid whose context-sensitive half-life remains constant (approx. 3-4 mins) regardless of the duration of infusion. 2. **Opioid-Induced Hyperalgesia:** Rapid offset can lead to "acute opioid tolerance" or hyperalgesia; therefore, longer-acting analgesics must be administered before stopping the infusion. 3. **Side Effects:** Can cause significant bradycardia and chest wall rigidity if administered too rapidly.

Q: Which of the following anesthetic agents is known to cause dissociative anesthesia?

Ketamine. **Explanation:** **Ketamine** is the correct answer because it is the classic agent used to induce **dissociative anesthesia**. This unique state is characterized by profound analgesia, amnesia, and a "trance-like" state where the patient appears awake (eyes may remain open with a slow nystagmic gaze) but is disconnected from the environment and sensory input. * **Mechanism:** Ketamine acts primarily as a non-competitive antagonist at the **NMDA (N-methyl-D-aspartate) receptors**. It causes functional dissociation between the thalamocortical and limbic systems. **Why other options are incorrect:** * **Thiopentone:** An ultra-short-acting barbiturate used for induction. It causes generalized CNS depression (GABA-A agonist) rather than dissociation. * **Suxamethonium (Succinylcholine):** A depolarizing neuromuscular blocker used for muscle relaxation/intubation. It has no anesthetic or analgesic properties. * **Diazepam:** A benzodiazepine used for sedation and anxiolysis. While it causes amnesia, it does not produce the specific state of dissociative anesthesia. **High-Yield Clinical Pearls for NEET-PG:** * **Hemodynamics:** Unlike most induction agents, Ketamine is **sympathomimetic** (increases HR, BP, and CO), making it the drug of choice for **hypovolemic shock**. * **Airway:** It preserves laryngeal reflexes and causes bronchodilation (drug of choice for **status asthmaticus**). * **Side Effects:** Known for causing **emergence delirium** (hallucinations), which can be pre-treated with benzodiazepines (e.g., Midazolam). * **Contraindications:** Avoid in patients with increased intracranial pressure (ICP) or intraocular pressure (IOP).

Q: Which modality is best utilized for neuromuscular monitoring during the maintenance of anesthesia?

Train of four. **Explanation:** **Train of Four (TOF)** is the gold standard for monitoring neuromuscular blockade during the maintenance phase of anesthesia. It involves four supramaximal stimuli delivered at 2 Hz (every 0.5 seconds). It is preferred because it is **non-invasive, does not require a baseline (pre-relaxant) value, and is highly sensitive** in assessing the degree of competitive (non-depolarizing) block. By comparing the strength of the fourth twitch (T4) to the first (T1), clinicians can quantify the "TOF ratio," which guides the titration of muscle relaxants and ensures safe recovery. **Why other options are incorrect:** * **Single Twitch:** Requires a pre-drug baseline for comparison. It is a "yes/no" indicator of block but cannot quantify the depth of the block or the degree of recovery. * **Tetanic Stimulation:** Involves high-frequency (50-100 Hz) stimulation. It is painful and can lead to "post-tetanic facilitation," which temporarily alters the neuromuscular junction, making subsequent monitoring inaccurate. * **Post-Tetanic Count (PTC):** This is specifically used to monitor **deep neuromuscular blockade** when the TOF count is zero. It is not the primary modality for routine maintenance but rather a specialized tool for profound paralysis. **Clinical Pearls for NEET-PG:** * **TOF Ratio for Extubation:** A ratio of **>0.9** (at the adductor pollicis) is required to safely exclude residual paralysis and allow extubation. * **Site of Monitoring:** The **Adductor Pollicis** (Ulnar nerve) is the most common site for monitoring recovery, while the **Orbicularis Oculi** (Facial nerve) better reflects the blockade of the diaphragm. * **Fade:** The progressive diminution of twitch response (Fade) is a hallmark of **Non-depolarizing** (Phase I) and **Depolarizing** (Phase II) blocks.

Question 1

Which opioid can cause tachycardia?

Accepted Answer

Pethidine

Answer

Fentanyl

Answer

Remifentanyl

Answer

Morphine

Question 2

Which of the following is NOT an intravenous anesthetic?

Accepted Answer

Desflurane

Answer

Propofol

Answer

Opioids

Answer

Ketamine

Question 3

Which of the following is not an amino steroid derivative?

Accepted Answer

Alcuronium

Answer

Vecuronium

Answer

Pancuronium

Answer

Pipecuronium

Question 4

A 40-year-old female underwent surgery. Postoperatively, she stated she was aware of preoperative events. Intraoperative awareness is evaluated by?

Accepted Answer

Bispectral imaging

Answer

Pulse oximetry

Answer

Colour doppler

Answer

End tidal CO2

Question 5

Oxygen is administered during anesthesia to prevent which of the following?

Accepted Answer

Hypoxia

Answer

Pain

Answer

Hypercapnia

Answer

Hypotension

Question 6

Dissociative sedation and analgesia, as described by Robert and Rosebaum in 1971, is associated with what concentration range of N2O?

Accepted Answer

50 to 70% N2O

Answer

5 to 20% N2O

Answer

20 to 30% N2O

Answer

30 to 50% N2O

Question 7

Which of the following is true regarding Remifentanil?

Accepted Answer

All of these

Answer

Useful for short painful procedures

Answer

Metabolized by plasma esterases

Answer

Equipotent as fentanyl

Question 8

Thiopentone is contraindicated in which of the following conditions?

Accepted Answer

Acute intermittent porphyria

Answer

Narcoanalysis

Answer

Neurosurgery

Answer

Induction of anaesthesia

Question 9

Which of the following anesthetic agents is known to cause dissociative anesthesia?

Accepted Answer

Ketamine

Answer

Thiopentone

Answer

Suxamethonium

Answer

Diazepam

Question 10

Which modality is best utilized for neuromuscular monitoring during the maintenance of anesthesia?

Accepted Answer

Train of four

Answer

Single twitch

Answer

Tetanic stimulation

Answer

Post-tetanic stimulation

General Anesthesia — MCQs

General Anesthesia — MCQs

On this page

Practice by Chapter

Want unlimited practice?