Complications in Anesthesia Practice Questions

Q: Which agent can cause malignant hyperthermia?

Succinylcholine. **Explanation:** **Malignant Hyperthermia (MH)** is a rare but life-threatening pharmacogenetic hypermetabolic disorder of skeletal muscle. It is triggered by exposure to specific anesthetic agents in genetically susceptible individuals (primarily due to mutations in the **RYR1 gene**, which encodes the Ryanodine receptor). **Why Succinylcholine is Correct:** Succinylcholine, a depolarizing neuromuscular blocker, and all **volatile inhalational anesthetics** (e.g., Halothane, Isoflurane, Sevoflurane) are the primary triggers for MH. These agents cause an uncontrolled release of calcium from the sarcoplasmic reticulum, leading to sustained muscle contraction, hypermetabolism, excessive heat production, and rhabdomyolysis. **Analysis of Incorrect Options:** * **B. Dantrolene:** This is the **treatment of choice** for MH. It acts by binding to the RYR1 receptor and inhibiting the release of calcium from the sarcoplasmic reticulum. * **C. Gallamine:** This is a non-depolarizing neuromuscular blocker. Non-depolarizing agents (like Vecuronium or Atracurium) do not trigger MH and are considered safe. * **D. Ketamine:** This is an intravenous induction agent. It is not a trigger for MH. Other safe agents include Propofol, Etomidate, and Opioids. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest Sign:** Increase in **End-Tidal CO₂ (ETCO₂)** despite increased ventilation. * **Clinical Features:** Masseter muscle rigidity (often the first physical sign), tachycardia, hyperthermia (late sign), and metabolic acidosis. * **Gold Standard Test:** Caffeine Halothane Contracture Test (CHCT) on a muscle biopsy. * **Management:** Stop the trigger, 100% O₂, and administer **Dantrolene (2.5 mg/kg IV)**. Use a "charcoal filter" if the same anesthesia machine must be used.

Q: What is the most common cause of death after anesthesia?

Cardiac arrest. **Explanation:** **Cardiac arrest** is the leading cause of perioperative mortality. In the context of anesthesia, cardiac arrest most commonly results from **respiratory failure** (hypoxemia due to airway obstruction or inadequate ventilation) or **cardiovascular collapse** (due to drug overdose, myocardial infarction, or severe hemorrhage). While modern monitoring like pulse oximetry and capnography has significantly reduced anesthesia-related mortality, sudden cardiac events remain the terminal event in most fatal cases. **Analysis of Incorrect Options:** * **Hypothermia (A):** While common in the OR due to cold ambient temperatures and cold IV fluids, it typically leads to morbidities like shivering, coagulopathy, and delayed drug metabolism, but is rarely a direct cause of death. * **Hypotension (B):** This is a frequent side effect of induction agents and neuraxial anesthesia. While severe hypotension can lead to organ ischemia, it is considered a *precursor* or a sign rather than the ultimate cause of death itself. * **Atelectasis (D):** This is the most common **postoperative pulmonary complication**. While it can lead to shunting and hypoxemia, it is usually manageable and does not result in immediate mortality unless it leads to severe secondary pneumonia or respiratory failure. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of anesthesia-related cardiac arrest:** Airway-related events (e.g., "cannot intubate, cannot ventilate"). * **Most common cause of death in the immediate postoperative period:** Respiratory complications (Hypoventilation). * **Most common cause of overall perioperative mortality (within 30 days):** Myocardial Infarction (MI). * **Triage Priority:** Always remember the **ABC** (Airway, Breathing, Circulation) sequence; failure in any of these leads to the final common pathway: Cardiac Arrest.

Q: Which of the following is NOT true about the Oculocardiac reflex?

Preoperative glycopyrrolate is not helpful for prevention.. The **Oculocardiac Reflex (OCR)**, also known as the Aschner-Dagnini reflex, is a common intraoperative phenomenon, particularly in ophthalmic and maxillofacial surgeries. ### **Explanation of the Correct Option** **Option B is the correct answer because it is a false statement.** While intramuscular preoperative glycopyrrolate or atropine was historically used, it is now considered **ineffective** for preventing OCR due to its short duration of action and the "escape" phenomenon. However, **intravenous (IV) glycopyrrolate or atropine** administered immediately before or during the procedure is highly effective in preventing or treating the bradycardia associated with this reflex. ### **Analysis of Incorrect Options** * **Option A:** The reflex arc is indeed **trigeminovagal**. The afferent limb is the ophthalmic division of the **Trigeminal nerve (CN V)**, and the efferent limb is the **Vagus nerve (CN X)**, leading to bradycardia or arrhythmias. * **Option C:** Pressure on the eyeball (e.g., during retrobulbar blocks or ocular trauma) is a classic trigger for the reflex. * **Option D:** Traction on the extraocular muscles, most commonly the **medial rectus**, is the most potent stimulus for inducing the OCR during strabismus surgery. ### **High-Yield Clinical Pearls for NEET-PG** * **The 5 and 10 Reflex:** Afferent is CN **5** (Trigeminal); Efferent is CN **10** (Vagus). * **Management Protocol:** 1. Stop the stimulus (Ask the surgeon to release traction). 2. Ensure adequate oxygenation and ventilation. 3. If persistent, administer **IV Atropine** (0.02 mg/kg). 4. Infiltrate the muscle with local anesthetic if the reflex recurs. * **Fatigue Phenomenon:** The reflex exhibits "tiring" or tachyphylaxis, meaning it diminishes with repeated stimulation.

Q: What is the commonest sign of aspiration pneumonitis?

Tachypnea. **Explanation:** **Mendelson’s Syndrome (Aspiration Pneumonitis)** occurs due to the inhalation of acidic gastric contents (pH 25ml). This leads to a chemical burn of the pulmonary parenchyma, resulting in immediate physiological responses. **Why Tachypnea is the Correct Answer:** **Tachypnea** is the **earliest and most common clinical sign** of aspiration pneumonitis. The presence of acidic fluid in the alveoli triggers an inflammatory response and disrupts surfactant, leading to micro-atelectasis. This decreases lung compliance and stimulates J-receptors, causing a rapid, shallow breathing pattern. While other signs develop as the condition progresses, an increase in respiratory rate is the most sensitive initial indicator. **Analysis of Incorrect Options:** * **Cyanosis:** This is a late sign indicating severe hypoxemia and significant ventilation-perfusion (V/Q) mismatch. It is not the most common or earliest sign. * **Crepitations (Rales):** These occur due to the presence of fluid and exudate in the alveoli. While common, they may take time to develop fully and are often preceded by tachypnea. * **Rhonchi:** These represent airway narrowing or secretions in larger bronchi. While they can occur due to bronchospasm (a common feature), they are less consistent than tachypnea. **High-Yield Clinical Pearls for NEET-PG:** * **Mendelson’s Criteria:** Gastric pH ** 0.4 ml/kg (approx. 25 ml)**. * **Commonest Site:** The **Right Lower Lobe** (specifically the superior segment) is the most frequent site of aspiration due to the more vertical anatomy of the right main bronchus. * **Management:** Immediate treatment involves oropharyngeal suctioning. **Prophylactic antibiotics and steroids are NOT recommended** for chemical pneumonitis unless secondary bacterial infection occurs.

Question 1

What is true about post-dural puncture headache?

Accepted Answer

Using a small bore needle helps prevent it.

Answer

It is common in the elderly.

Answer

Early ambulation increases its incidence.

Answer

All of the above.

Question 2

Which agent can cause malignant hyperthermia?

Accepted Answer

Succinylcholine

Answer

Dantrolene

Answer

Gallamine

Answer

Ketamine

Question 3

What is the most common cause of death after anesthesia?

Accepted Answer

Cardiac arrest

Answer

Hypothermia

Answer

Hypotension

Answer

Atelectasis

Question 4

Which of the following is NOT true about the Oculocardiac reflex?

Accepted Answer

Preoperative glycopyrrolate is not helpful for prevention.

Answer

It is mediated by the trigeminovagal route.

Answer

It can be induced by pressure on the eyeball.

Answer

It is mediated by traction on the medial rectus muscle.

Question 5

A patient was anesthetized with halothane and nitrous oxide, and tubocurarine was used for skeletal muscle relaxation. The patient became hypertensive with marked muscle rigidity and hyperthermia. Lab reports showed hyperkalemia and acidosis. This complication was caused by:

Accepted Answer

Excessive release of calcium from the sarcoplasmic reticulum

Answer

Block of autonomic ganglia by tubocurarine

Answer

Pheochromocytoma

Answer

Activation of brain dopamine receptors by halothane

Question 6

A patient is placed in the Trendelenburg position during surgery. What is the primary rationale for this positioning if an air embolism is suspected?

Accepted Answer

To keep a left ventricular air bubble away from the coronary artery ostia.

Answer

To trap air in the right ventricle.

Answer

To prevent air from passing through the foramen ovale.

Answer

To prevent air from entering the left ventricle.

Question 7

Use of nitrous oxide is contraindicated in all of the following surgeries except?

Accepted Answer

Exentration operation

Answer

Cochlear implant

Answer

Microlaryngeal surgery

Answer

Vitrioretinal surgery

Question 8

Which of the following is the first treatment for an anesthetized patient experiencing bronchospasm?

Accepted Answer

Administer additional anesthetic

Answer

Administer inhalational beta-2 agonists

Answer

Administer intravenous epinephrine

Answer

Administer neuromuscular blocking agent

Question 9

What is the commonest sign of aspiration pneumonitis?

Accepted Answer

Tachypnea

Answer

Cyanosis

Answer

Crepitations

Answer

Rhonchi

Question 10

A woman is posted for elective cholecystectomy. Her preoperative clinical evaluation and airway assessment were normal. In the operating room, she was attached to the monitors and an antibiotic was administered. Suddenly she became pulseless and unresponsive. What is the immediate next step in her management?

Accepted Answer

Start chest compressions

Answer

Check for breathing

Answer

Call for help/additional personnel

Answer

Give two rescue breaths

Complications in Anesthesia — MCQs

Complications in Anesthesia — MCQs

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