Complications in Anesthesia Practice Questions

Q: A 45-year-old woman undergoing general anesthesia for cholecystectomy suddenly develops tachycardia (140/min), rising end-tidal CO2 (65 mm Hg), muscle rigidity, and temperature increasing from 98.6°F to 104°F (37°C to 40°C) within 20 minutes. Her father reportedly died during surgery years ago. Apply the appropriate immediate intervention.

Discontinue triggering agents and administer dantrolene. ***Discontinue triggering agents and administer dantrolene*** - The patient is experiencing **Malignant Hyperthermia (MH)**, a hypermetabolic crisis triggered by **volatile anesthetics** or **succinylcholine**, characterized by rising **end-tidal CO2**, tachycardia, and muscle rigidity. - Immediate management requires stopping the trigger and administering **dantrolene**, which acts by inhibiting **calcium release** from the **ryanodine receptor (RYR1)** in the sarcoplasmic reticulum. *Administer broad-spectrum antibiotics* - While fever and tachycardia can suggest sepsis, the rapid onset of **hypercapnia** and **muscle rigidity** under anesthesia is pathognomonic for **Malignant Hyperthermia**. - Antibiotics will not treat the underlying **hypermetabolic state** caused by uncontrolled intracellular calcium levels. *Hyperventilate and administer neuromuscular blockers* - Though hyperventilation with **100% oxygen** is part of supportive care, common neuromuscular blockers like **succinylcholine** can actually trigger or worsen the crisis. - Rigidity in MH is caused by direct calcium-induced contraction at the **myocyte level**, so typical paralytics may be ineffective and do not address the primary pathology. *Apply external cooling and continue anesthesia* - Cooling is a necessary supportive measure, but **continuing anesthesia** with triggering agents is lethal due to the ongoing metabolic storm. - External cooling alone cannot stop the **intracellular calcium surge** that drives the rapid rise in body temperature. *Continue surgery and administer antipyretics* - Antipyretics like acetaminophen work on the **hypothalamic set point** and are ineffective for the **peripheral heat production** seen in MH. - MH is a medical emergency with a high mortality rate; surgery must be **aborted** or transitioned to non-triggering agents (like TIVA) immediately.

Q: Propofol infusion syndrome is characterized by

Bradycardia. **Explanation:** **Propofol Infusion Syndrome (PRIS)** is a rare but potentially fatal complication associated with high-dose (>4 mg/kg/hr) and long-term (>48 hours) infusions of propofol. **Why Bradycardia is Correct:** The pathophysiology of PRIS involves the inhibition of mitochondrial oxidative phosphorylation and fatty acid oxidation. This creates a severe energy deficit in cardiac and skeletal muscles. The hallmark cardiac manifestation is **refractory bradycardia**, which often progresses to asystole. This bradycardia is typically preceded by ECG changes such as right bundle branch block and Brugada-like ST-segment elevation in the precordial leads (V1-V3). **Analysis of Incorrect Options:** * **A. Hypokalemia:** Incorrect. PRIS is characterized by **Hyperkalemia**. This occurs due to extensive rhabdomyolysis (muscle breakdown) resulting from the metabolic failure of myocytes. * **B. Hypolipidemia:** Incorrect. PRIS causes **Hypertriglyceridemia**. Since propofol is delivered in a lipid emulsion, and PRIS impairs lipid metabolism, serum triglyceride levels rise significantly. * **D. Tachycardia:** Incorrect. While early stress responses might show transient tachycardia, the diagnostic feature and terminal event of PRIS is progressive, treatment-resistant bradycardia. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Pentad of PRIS:** Cardiomyopathy (Bradycardia/Heart Failure), Metabolic Acidosis (Anion gap), Rhabdomyolysis, Hyperkalemia, and Renal Failure. * **Risk Factors:** High doses, prolonged duration, critical illness, concomitant use of glucocorticoids or catecholamines, and low carbohydrate intake. * **Management:** Immediate cessation of propofol infusion and supportive care (hemodialysis for hyperkalemia/acidosis and pacing for bradycardia).

Q: A 'Mill Wheel Murmur' is heard in which of the following conditions?

Air embolism. **Explanation:** The **Mill Wheel Murmur** is a pathognomonic clinical sign of a **Venous Air Embolism (VAE)**. It is a loud, splashing, churning sound heard over the precordium, caused by the mixing of air and blood within the right ventricle. This "gas lock" obstructs the outflow of blood from the right ventricle into the pulmonary artery, leading to acute right heart failure and cardiovascular collapse. **Why the other options are incorrect:** * **Aortic Dissection:** Typically presents with a tearing chest pain radiating to the back. If a murmur is present, it is usually the diastolic murmur of **aortic regurgitation** (if the dissection involves the aortic root). * **Coarctation of Aorta:** Characterized by a systolic murmur heard best over the **left infraclavicular area and the back** (interscapular), often associated with radio-femoral delay. * **Abdominal Aortic Aneurysm (AAA):** Usually presents as a pulsatile abdominal mass. If a sound is heard, it is an **abdominal bruit**, not a precordial murmur. **High-Yield Clinical Pearls for NEET-PG:** * **Most Sensitive Monitor for VAE:** Transesophageal Echocardiography (TEE). * **Most Sensitive Non-Invasive Monitor:** Precordial Doppler (placed at the 2nd–6th intercostal space, right of the sternum). * **Early Sign:** Decrease in End-Tidal CO2 (ETCO2) due to increased dead space. * **Management:** Place the patient in **Durant’s Position** (Left lateral decubitus and Trendelenburg) to trap air in the apex of the right ventricle, away from the pulmonary outflow tract. Aspirate air via a Central Venous Catheter.

Q: A surgical resident has accidentally administered an intra-arterial injection of thiopental sodium to a patient. The arm has blanched below the level of the injection. Which of the following is NOT recommended for the management?

Immediately remove the needle and apply a warm towel. **Explanation:** Accidental intra-arterial injection of Thiopental sodium (an alkaline solution with pH 10.5) is a medical emergency. It causes immediate **intense pain, vasospasm, and crystal formation**, leading to thrombosis and distal limb ischemia (blanching). **Why Option A is the Correct Answer (The "NOT" recommended action):** The most critical rule in managing intra-arterial injection is **NOT to remove the needle immediately**. The needle should be left in situ to serve as a portal for administering emergency vasodilators (like 1% Procaine, Lidocaine, or Papaverine) directly into the affected artery to counteract vasospasm and dilute the drug. **Analysis of Incorrect Options (Recommended Managements):** * **Option B (Brachial Plexus Block):** This is recommended as it produces sympathetic blockade, leading to vasodilation and improved collateral circulation, while also providing pain relief. * **Option C (IV Heparin):** Systemic anticoagulation is essential to prevent the progression of thrombosis caused by the endarteritis and crystal deposition. * **Option D (Analgesics):** Severe pain triggers further sympathetic-mediated vasoconstriction; therefore, aggressive pain management is a standard part of the protocol. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism of Injury:** Thiopental crystals precipitate in the blood (due to pH change), causing mechanical obstruction and a chemical endarteritis. * **First Step:** Leave the needle in place. * **Drug of Choice for Vasodilation:** **Papaverine** or **1% Procaine** (Procaine is also an acid, which helps neutralize the alkaline Thiopental). * **Other Treatments:** Stellat ganglion block, Phenoxybenzamine, and elevating the limb (to improve venous drainage).

Question 1

A 45-year-old woman undergoing general anesthesia for cholecystectomy suddenly develops tachycardia (140/min), rising end-tidal CO2 (65 mm Hg), muscle rigidity, and temperature increasing from 98.6°F to 104°F (37°C to 40°C) within 20 minutes. Her father reportedly died during surgery years ago. Apply the appropriate immediate intervention.

Accepted Answer

Discontinue triggering agents and administer dantrolene

Answer

Administer broad-spectrum antibiotics

Answer

Hyperventilate and administer neuromuscular blockers

Answer

Apply external cooling and continue anesthesia

Answer

Continue surgery and administer antipyretics

Question 2

Propofol infusion syndrome is characterized by

Accepted Answer

Bradycardia

Answer

Hypokalemia

Answer

Hypolipidemia

Answer

Tachycardia

Question 3

A 'Mill Wheel Murmur' is heard in which of the following conditions?

Accepted Answer

Air embolism

Answer

Aortic dissection

Answer

Coarctation of aorta

Answer

Abdominal aortic aneurysm

Question 4

A surgical resident has accidentally administered an intra-arterial injection of thiopental sodium to a patient. The arm has blanched below the level of the injection. Which of the following is NOT recommended for the management?

Accepted Answer

Immediately remove the needle and apply a warm towel

Answer

Perform a brachial plexus block on the affected side

Answer

Administer IV heparin

Answer

Administer analgesics

Question 5

With respect to cardiac arrests occurring during anesthesia, which of the following statements are correct?

Accepted Answer

The most common preceding arrhythmia is bradycardia and the most common cause is failure of ventilation.

Answer

The most common preceding arrhythmia is bradycardia and most occur during emergence from anesthesia.

Answer

The most common preceding arrhythmia is bradycardia.

Answer

The most common preceding arrhythmia is bradycardia and most are considered unpreventable and untreatable.

Complications in Anesthesia — MCQs

Complications in Anesthesia — MCQs

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