General Anesthesia Practice Questions

Q: All statements regarding the use of magnesium sulfate are correct EXCEPT?

Decreases neuromuscular blockade. **Explanation:** Magnesium sulfate ($MgSO_4$) is a versatile drug in anesthesia and critical care, primarily acting as a **NMDA receptor antagonist** and a **calcium channel blocker**. **Why Option C is the correct (incorrect statement):** Magnesium sulfate **potentiates** (increases), rather than decreases, the effects of both depolarizing (Succinylcholine) and non-depolarizing neuromuscular blocking agents (NDMRAs). It achieves this by: 1. Inhibiting the pre-synaptic release of Acetylcholine (ACh) at the neuromuscular junction. 2. Reducing the sensitivity of the post-synaptic membrane to ACh. 3. Decreasing the excitability of the muscle fiber membrane. *Clinical Note: Muscle relaxant doses should be reduced when a patient is on Magnesium therapy.* **Analysis of other options:** * **Option A (Spinal Anesthesia):** Magnesium is used as an adjuvant in spinal anesthesia to prolong the duration of sensory and motor blocks and improve post-operative analgesia. * **Option B (Seizure Prophylaxis):** It is the **drug of choice** for preventing and treating seizures in Eclampsia (MAGPIE trial). * **Option D (Pre-emptive Analgesia):** By blocking NMDA receptors in the spinal cord, it prevents "wind-up" phenomenon and central sensitization, making it an effective adjunct for pre-emptive and multi-modal analgesia. **High-Yield Clinical Pearls for NEET-PG:** * **Therapeutic Range:** 4–7 mEq/L. * **Toxicity Sequence:** Loss of patellar reflex (8–10 mEq/L) → Respiratory depression (10–12 mEq/L) → Cardiac arrest (>25 mEq/L). * **Antidote:** 10% Calcium Gluconate (10 ml over 10 mins). * **Drug of Choice:** For Torsades de Pointes.

Q: Which opioid does not require kidney and liver for metabolism?

Remifentanyl. **Explanation:** The correct answer is **Remifentanil**. **1. Why Remifentanil is correct:** Remifentanil is unique among opioids because it contains an **ester linkage**. This structure allows it to undergo rapid hydrolysis by **non-specific plasma and tissue esterases**. Because its metabolism is independent of organ function, it has an ultra-short duration of action (half-life of <10 minutes) and does not accumulate even after prolonged infusions. This makes it the ideal choice for patients with end-stage liver or renal failure. **2. Why the other options are incorrect:** * **Fentanyl, Sufentanil, and Alfentanil:** These are all synthetic phenylpiperidine derivatives that lack the ester side chain. They are primarily metabolized by the **liver** (specifically via the Cytochrome P450 system, mainly CYP3A4) and their metabolites are excreted by the **kidneys**. In patients with organ dysfunction, these drugs can have a prolonged effect and increased toxicity. **3. High-Yield Clinical Pearls for NEET-PG:** * **Context-Sensitive Half-Time:** Remifentanil has the shortest context-sensitive half-time (approx. 3–4 minutes), which remains constant regardless of the duration of infusion. * **Organ Independence:** Like **Atracurium/Cisatracurium** (muscle relaxants), Remifentanil is "organ-independent" for its metabolism. * **Side Effect:** Rapid offset can lead to immediate postoperative pain; therefore, a longer-acting analgesic must be administered before stopping a Remifentanil infusion. * **Potency Order:** Sufentanil (Most potent) > Remifentanil > Fentanyl > Alfentanil (Least potent).

Q: Which intravenous anesthetic agent should be avoided in a patient with bronchoconstriction?

Thiopentone. **Explanation:** The correct answer is **Thiopentone (Option A)**. **Why Thiopentone is avoided:** Thiopentone is a barbiturate that triggers the release of **histamine** from mast cells. Histamine causes smooth muscle contraction in the airways, leading to **bronchospasm**. Additionally, thiopentone does not sufficiently suppress laryngeal and cough reflexes; if the airway is manipulated (e.g., intubation) under light planes of thiopentone anesthesia, it can precipitate severe reflex bronchospasm. Therefore, it is strictly avoided in patients with active asthma or reactive airway disease. **Analysis of Incorrect Options:** * **Ketamine (Option D):** This is the **drug of choice** for induction in patients with bronchoconstriction. It has potent bronchodilatory properties due to its sympathomimetic effects (catecholamine release) and direct relaxant effect on bronchial smooth muscle. * **Propofol (Option B):** It is a safe and frequently used agent in asthmatics. It effectively suppresses airway reflexes and has mild bronchodilatory properties, making it superior to thiopentone for laryngeal mask airway (LMA) insertion. * **Etomidate (Option C):** It is "respiratorily neutral." It does not cause histamine release and has minimal effects on airway resistance, making it safer than thiopentone for hemodynamically unstable asthmatic patients. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice for Induction in Asthma:** Ketamine. * **Inhalational Agent of Choice for Bronchodilation:** Sevoflurane (least pungent, potent bronchodilator). * **Avoid:** Thiopentone (histamine release) and Desflurane (pungent, can cause airway irritation/coughing). * **Pre-medication:** Hydrocortisone and nebulized β2-agonists are often used pre-operatively to optimize airway status.

Q: Lacrimation during anesthesia indicates which stage?

Stage III. **Explanation:** The correct answer is **Stage III (Surgical Anesthesia)**. This question refers to **Guedel’s Classification**, which describes the clinical signs of anesthesia progression using volatile agents like ether. **Why Stage III is correct:** Stage III is divided into four planes. **Lacrimation (tearing)** is a hallmark sign of **Plane 1 of Stage III**. During this stage, the patient transitions from the excitement of Stage II into a state of surgical anesthesia. While the blink reflex is lost, the presence of tears indicates a relatively light plane of anesthesia. As the patient moves deeper into Plane 2 and 3, lacrimation typically ceases. **Analysis of Incorrect Options:** * **Stage I (Analgesia):** Extends from induction to loss of consciousness. Reflexes remain intact, but lacrimation is not a defining clinical sign here. * **Stage II (Excitement/Delirium):** Characterized by struggling, breath-holding, and irregular respiration. While autonomic activity is high, lacrimation is specifically used to titrate depth within Stage III. * **Stage IV (Medullary Paralysis):** This is the stage of overdose. It is characterized by respiratory failure and vasomotor collapse. Lacrimation is absent as all reflex activities are abolished. **High-Yield Clinical Pearls for NEET-PG:** * **Guedel’s Stages** were originally described for **Diethyl Ether**; they are less distinct with modern intravenous agents (like Propofol) due to their rapid onset. * **Stage II Danger:** This is the most hazardous stage due to the risk of laryngospasm, vomiting, and cardiac arrhythmias. * **Pupillary Signs:** Pupils are dilated in Stage II (sympathetic overactivity), constricted in Stage III Plane 1-2, and widely dilated in Stage IV (paralysis). * **Respiration:** Becomes regular and automatic at the onset of Stage III.

Q: Anesthetic management of a 30-year-old lady with myasthenia gravis includes all of the following except?

Generous doses of opioids. **Explanation:** The anesthetic management of **Myasthenia Gravis (MG)** focuses on minimizing respiratory depression and managing the altered response to neuromuscular blocking agents. **Why "Generous doses of opioids" is the correct (except) option:** Patients with MG have significant bulbar and respiratory muscle weakness. **Opioids** cause dose-dependent respiratory depression and can suppress the cough reflex, leading to a high risk of postoperative respiratory failure and aspiration. Therefore, opioids should be used very cautiously (titrated to effect) or avoided in favor of multimodal analgesia; "generous doses" are contraindicated. **Analysis of other options:** * **Regional Anesthesia (A):** This is often the preferred technique (where applicable) as it avoids the need for systemic neuromuscular blockers and airway manipulation, reducing the risk of a myasthenic crisis. * **Corticosteroids (B):** Many MG patients are on chronic steroid therapy to manage their autoimmune condition. These should be continued perioperatively, and "stress doses" may be required to prevent adrenal insufficiency. * **Dose of Anticholinesterase (C):** Pyridostigmine is often reduced or withheld on the morning of surgery to avoid interactions with muscle relaxants and to minimize vagotonic effects (like excessive secretions/bradycardia), though this is tailored to the patient's severity. **High-Yield NEET-PG Pearls:** 1. **Muscle Relaxant Response:** MG patients are **exquisitely sensitive** to Non-depolarizing Muscle Relaxants (NDMRs) like Vecuronium (use 1/10th dose) and **resistant** to Depolarizing agents (Succinylcholine). 2. **Osserman Classification:** Used to grade the severity of MG. 3. **Predictors of Post-op Ventilation:** Disease duration >6 years, chronic respiratory disease, pyridostigmine dose >750mg/day, and Vital Capacity <2.9L. 4. **Reversal:** Sugammadex is preferred over Neostigmine to avoid cholinergic crisis.

Q: Volatile inhalational anesthetics contribute to which of the following components of general anesthesia, except?

Analgesia. **Explanation:** General anesthesia is defined as a reversible state of drug-induced unconsciousness consisting of four primary components: **Amnesia/Hypnosis (Unconsciousness), Analgesia, Muscle Relaxation, and Reflex Suppression.** While volatile inhalational anesthetics (e.g., Sevoflurane, Isoflurane, Desflurane) are potent hypnotics, they are **poor analgesics**. At clinical concentrations, they do not provide sufficient pain relief to suppress the surgical stress response. Therefore, they must be supplemented with opioids (like Fentanyl) or regional blocks to achieve the "Analgesia" component of the anesthetic triad. **Analysis of Options:** * **Loss of Consciousness (A):** This is the primary effect of volatile agents. They act on GABA-A receptors and various ion channels in the brain to induce a state of hypnosis and amnesia. * **Loss of Reflex (B):** Volatile agents effectively suppress autonomic and motor responses to noxious stimuli, contributing to the stability of the patient during surgery. * **Muscle Relaxation (D):** Inhalational agents produce dose-dependent skeletal muscle relaxation by acting on the spinal cord and potentiating the effects of neuromuscular blocking agents. * **Analgesia (C):** As noted, volatile agents lack significant analgesic properties. Nitrous Oxide ($N_2O$) is the only common inhalational agent that provides significant analgesia, but it is a gas, not a volatile liquid. **High-Yield NEET-PG Pearls:** * **MAC (Minimum Alveolar Concentration):** A measure of potency; it specifically measures the concentration required to prevent movement (reflex) in 50% of patients, not analgesia. * **Nitrous Oxide Exception:** Unlike volatile agents, $N_2O$ has strong analgesic properties but is a weak hypnotic (MAC > 100%). * **Ketamine:** The only induction agent that provides all three: Unconsciousness, Analgesia, and Sympathetic stimulation.

Q: The triad of general anaesthesia includes which of the following components?

Unconsciousness, analgesia, and muscle relaxation. The **Triad of General Anaesthesia** (originally proposed by Gray and Rees) represents the three fundamental physiological states required to perform surgery safely and effectively. ### 1. Why Option A is Correct The goal of balanced anesthesia is to achieve a state where the patient is unaware, pain-free, and physically still. The components are: * **Unconsciousness (Narcosis/Hypnosis):** Ensures the patient is unaware of the surgical procedure and has no memory of it (amnesia). * **Analgesia:** Suppression of the sensory perception of pain and the autonomic responses to surgical stimuli. * **Muscle Relaxation (Areflexia):** Provides optimal operating conditions for the surgeon by paralyzing skeletal muscles and suppressing motor reflexes. ### 2. Why Other Options are Incorrect * **Option B:** **Anxiolysis** (reduction of anxiety) is a component of *pre-medication*, not a core requirement of the intraoperative triad. * **Option C:** **Sedation** is a depressed level of consciousness where the patient may still respond to stimuli; general anesthesia requires complete unconsciousness. * **Option D:** **Dissociation** is specific to "Dissociative Anesthesia" (e.g., Ketamine), where the patient appears awake but is detached from the environment. It is a type of anesthesia, not a component of the classic triad. ### 3. High-Yield NEET-PG Pearls * **Balanced Anesthesia:** This modern concept uses a combination of drugs (e.g., Propofol for induction, Opioids for analgesia, and Vecuronium for relaxation) to achieve the triad while minimizing the side effects of any single agent. * **The Fourth Component:** Modern texts often add **Amnesia** or **Autonomic Stability** as a fourth pillar, forming a "tetrad." * **Guedel’s Stages:** Remember that these stages (I-IV) specifically describe anesthesia induced by **Ether**; they are rarely seen with modern rapid-acting intravenous agents.

Question 1

All statements regarding the use of magnesium sulfate are correct EXCEPT?

Accepted Answer

Decreases neuromuscular blockade

Answer

Used in spinal anesthesia

Answer

Used in seizure prophylaxis

Answer

Used in pre-emptive analgesia

Question 2

Ketamine is NOT indicated in which of the following conditions?

Accepted Answer

Increased intracranial pressure

Answer

Full stomach

Answer

Pediatric patient

Answer

Asthma patient

Question 3

Which opioid does not require kidney and liver for metabolism?

Accepted Answer

Remifentanyl

Answer

Sufentanil

Answer

Alfentanyl

Answer

Fentanyl

Question 4

Which intravenous anesthetic agent should be avoided in a patient with bronchoconstriction?

Accepted Answer

Thiopentone

Answer

Propofol

Answer

Etomidate

Answer

Ketamine

Question 5

Lacrimation during anesthesia indicates which stage?

Accepted Answer

Stage III

Answer

Stage I

Answer

Stage II

Answer

Stage IV

Question 6

Anesthetic management of a 30-year-old lady with myasthenia gravis includes all of the following except?

Accepted Answer

Generous doses of opioids

Answer

Regional anesthesia

Answer

Corticosteroids

Answer

Dose of anticholinesterase to be decreased

Question 7

Volatile inhalational anesthetics contribute to which of the following components of general anesthesia, except?

Accepted Answer

Analgesia

Answer

Loss of consciousness

Answer

Loss of reflex

Answer

Muscle relaxation

Question 8

Relative contraindications for the administration of ketamine hydrochloride include all of the following EXCEPT?

Accepted Answer

Recent anterior myocardial infarction

Answer

Age < 5 years

Answer

History of epilepsy

Answer

Raised intracranial tension

Question 9

The triad of general anaesthesia includes which of the following components?

Accepted Answer

Unconsciousness, analgesia, and muscle relaxation

Answer

Anxiolysis, analgesia, and unconsciousness

Answer

Muscle relaxation, sedation, and analgesia

Answer

Dissociation, analgesia, and muscle relaxation

Question 10

Which of the following intravenous anesthetic agents interacts with tricyclic antidepressants?

Accepted Answer

Ketamine

Answer

Thiopentone

Answer

Propofol

Answer

Etomidate

General Anesthesia — MCQs

General Anesthesia — MCQs

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