Complications in Anesthesia Practice Questions

Q: All are true statements about malignant hyperthermia except?

Oral dantrolene is the drug of choice.. ### Explanation **Malignant Hyperthermia (MH)** is a life-threatening pharmacogenetic clinical syndrome triggered by volatile anesthetic gases and the depolarizing muscle relaxant succinylcholine. **Why Option D is the correct answer (False statement):** While **Dantrolene** is indeed the definitive treatment for MH, **oral dantrolene is ineffective** in an acute crisis. The drug of choice is **Intravenous (IV) Dantrolene**. It works by binding to the ryanodine receptor (RYR1), inhibiting the release of calcium from the sarcoplasmic reticulum into the myoplasm. The initial dose is 2.5 mg/kg IV, repeated until symptoms subside. **Analysis of other options:** * **Option A:** MH is inherited as an **autosomal dominant** trait with variable penetrance. It is most commonly associated with mutations in the **RYR1 gene** (ryanodine receptor). * **Option B:** TIVA (using drugs like Propofol and Opioids) is considered **safe**. MH is only triggered by "potent" volatile agents (Halothane, Isoflurane, Sevoflurane, Desflurane) and Succinylcholine. Nitrous oxide and Etomidate are also safe. * **Option C:** MH is a hypermetabolic state. The **earliest and most sensitive sign is a rise in End-Tidal CO2 (EtCO2)**. Masseter muscle rigidity (MMR) after succinylcholine administration is a classic warning sign. Hyperthermia is often a late sign. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Caffeine Halothane Contracture Test (CHCT) performed on a muscle biopsy. * **Earliest Sign:** Unexplained rise in EtCO2 (refractory to increased ventilation). * **Management Mnemonic:** "Help, Discontinue, Dantrolene" (Call for help, stop triggers, give IV Dantrolene). * **Associated Conditions:** Central Core Disease, King-Denborough Syndrome, and Multiminicore disease. * **Safe Agents:** Propofol, Thiopentone, Ketamine, Etomidate, Nondepolarizing NMBs (eg. Vecuronium), and Local Anesthetics.

Q: Which of the following is true regarding post-spinal headache?

It typically improves with caffeine administration.. **Explanation:** Post-Dural Puncture Headache (PDPH) is a common complication following spinal anesthesia, caused by the persistent leakage of cerebrospinal fluid (CSF) through the dural puncture site. This leads to low CSF pressure and compensatory cerebral vasodilation. **1. Why Option B is Correct:** Caffeine is a potent **cerebral vasoconstrictor**. By constricting the dilated cerebral vessels (which occur in response to low CSF pressure), caffeine helps alleviate the characteristic throbbing pain. It is often administered orally or intravenously (e.g., 500 mg Caffeine Sodium Benzoate) as a first-line conservative treatment. **2. Why Other Options are Incorrect:** * **Option A:** PDPH is classically **positional**. It worsens when the patient is upright and **improves significantly in the recumbent (supine) position** due to reduced hydrostatic pressure on the dural leak. * **Option C:** PDPH is primarily **volume-dependent**. The symptoms arise because the rate of CSF leak exceeds the rate of CSF production, leading to a loss of the "buoyancy" effect of the brain. * **Option D:** It rarely starts immediately. Symptoms typically manifest **12 to 48 hours** after the procedure. An immediate headache is more likely to be related to other causes like accidental air injection (pneumoencephalos). **High-Yield Clinical Pearls for NEET-PG:** * **Risk Factors:** More common in young females, pregnant patients, and when using large-bore or cutting-tip needles (e.g., Quincke). * **Prevention:** Use of small-gauge (25G–27G) **non-cutting/pencil-point needles** (e.g., **Sprotte or Whitacre**) significantly reduces incidence. * **Gold Standard Treatment:** For persistent or severe cases, the **Epidural Blood Patch** is the most effective treatment (success rate >90%). * **Character:** Typically bifrontal or occipital, radiating to the neck and shoulders.

Q: In which patient position is venous air embolism most commonly encountered?

Sitting. **Explanation:** **Venous Air Embolism (VAE)** occurs when there is a pressure gradient that allows atmospheric air to enter the venous circulation through an open, non-collapsible vein. **Why Sitting is Correct:** The sitting position is the most common scenario for VAE, particularly during **neurosurgical procedures** (e.g., posterior fossa surgery). In this position, the surgical site is significantly **above the level of the heart**. This creates a **negative pressure gradient** between the atmospheric air at the wound site and the sub-atmospheric pressure in the dural venous sinuses. Since dural sinuses are held open by bone or dura and cannot collapse, air is easily sucked into the venous system. **Why Other Options are Incorrect:** * **Supine:** The surgical site is generally at or near the level of the heart, minimizing the gravitational pressure gradient required for air entrainment. * **Prone:** While VAE can occur in the prone position (especially in spinal surgeries), the gradient is typically less pronounced than in the sitting position. * **Left Lateral:** This position is actually used as a **treatment** for VAE (Durant’s Maneuver). Placing the patient in the left lateral decubitus with Trendelenburg helps trap the air bubble in the apex of the right ventricle, preventing it from obstructing the pulmonary artery outflow tract. **High-Yield Clinical Pearls for NEET-PG:** * **Most Sensitive Monitor:** **Precordial Doppler** (detects the classic "mill-wheel murmur"). * **Gold Standard for Detection:** Transesophageal Echocardiography (TEE). * **Earliest Sign:** Decrease in **End-Tidal CO2 (EtCO2)** due to increased dead space. * **Management:** 100% Oxygen, flood the surgical field with saline, aspirate air via a Central Venous Catheter, and place the patient in the **Left Lateral Trendelenburg position**.

Q: A patient under inhalational anesthesia suddenly develops fever, increased heart rate and BP, acidosis, and arrhythmia during surgery. What is your first step of intervention?

Dantrolene. ### Explanation The clinical presentation of sudden hyperthermia, tachycardia, hypertension, metabolic acidosis, and arrhythmias during inhalational anesthesia is pathognomonic for **Malignant Hyperthermia (MH)**. **Why Dantrolene is the Correct Answer:** MH is a life-threatening hypermetabolic state triggered by volatile anesthetics (e.g., Halothane, Isoflurane) or Succinylcholine. It is caused by a genetic defect in the **Ryanodine Receptor (RYR1)**, leading to an uncontrolled release of calcium from the sarcoplasmic reticulum. **Dantrolene** is the specific antidote and the definitive first-line treatment. It works by binding to the RYR1 receptor and inhibiting calcium release, thereby reversing the muscle rigidity and hypermetabolic cascade. **Why Other Options are Incorrect:** * **B. Sodium Bicarbonate:** While used to treat the resulting metabolic acidosis, it is a supportive measure and does not address the underlying cause. * **C. Procainamide:** Used to treat arrhythmias in MH, but it is secondary to stabilizing the calcium release. Note: Calcium channel blockers are contraindicated in MH as they can worsen hyperkalemia. * **D. Antipyretics:** Fever in MH is due to internal muscular metabolism, not a change in the hypothalamic set-point. Aspirin or Paracetamol are ineffective. **NEET-PG High-Yield Pearls:** * **Earliest Sign:** Increase in **End-Tidal CO₂ (ETCO₂)** despite increased ventilation. * **Late Sign:** Hyperthermia (can rise at 1°C every 5 minutes). * **Gold Standard Diagnosis:** Caffeine Halothane Contracture Test (CHCT) on muscle biopsy. * **Management Mnemonic:** "Stop, Hyperventilate, Dantrolene" (Stop triggers, 100% O₂, and give Dantrolene 2.5 mg/kg IV).

Q: A patient develops the arrhythmia shown in the ECG below, intra-operatively. What is the drug of choice (DOC)?

Propranolol. ***Propranolol*** - **Beta-blocker** that effectively controls **intraoperative sinus tachycardia** by blocking sympathetic stimulation and reducing heart rate. - Drug of choice for **perioperative tachycardia** due to its predictable onset and ability to counteract **catecholamine-induced** arrhythmias. *Adrenaline* - **Sympathomimetic agent** that would **worsen tachycardia** by increasing heart rate and cardiac contractility through beta-1 receptor stimulation. - Contraindicated in **sinus tachycardia** as it would exacerbate the underlying sympathetic overactivity. *Hyoscine* - **Anticholinergic drug** that can cause **tachycardia** as a side effect by blocking parasympathetic tone. - Would be inappropriate for treating tachycardia and may actually **worsen the arrhythmia** in this clinical scenario. *Neostigmine* - **Cholinesterase inhibitor** primarily used for **reversal of neuromuscular blockade** rather than arrhythmia management. - While it may have some **bradycardic effects**, it's not the appropriate first-line treatment for intraoperative tachycardia.

Q: Which of the following is NOT a complication of surgery performed in the sitting position?

Hemorrhage. The **sitting position** is commonly used in neurosurgery (posterior fossa surgeries) and shoulder surgeries. The primary physiological change in this position is that the surgical site is significantly **above the level of the heart**, creating a negative pressure gradient. ### Why Hemorrhage is the Correct Answer In the sitting position, venous pressure at the surgical site is low (often sub-atmospheric). This leads to **decreased surgical site bleeding** (improved visualization) rather than hemorrhage. Conversely, the main hemodynamic risk is **hypotension** due to venous pooling in the lower extremities, which reduces preload and cardiac output. ### Explanation of Other Options * **Venous Air Embolism (VAE):** This is the most feared complication. Because the surgical site is above the heart, a pressure gradient exists between the atmosphere and the open non-collapsible dural sinuses. Air is sucked into the venous system, potentially leading to cardiovascular collapse. * **Pneumocephalus:** As cerebrospinal fluid (CSF) drains out due to gravity, air can enter the cranial cavity to replace the lost volume (the "inverted pop bottle" effect), leading to tension pneumocephalus. * **Tongue Edema:** Prolonged neck flexion can cause macroglossia (tongue swelling) by obstructing venous and lymphatic drainage from the tongue and oropharynx. ### High-Yield Clinical Pearls for NEET-PG * **Most sensitive monitor for VAE:** Precordial Doppler (placed at the 2nd–4th intercostal space, right sternal border). * **Gold standard for VAE detection:** Transesophageal Echocardiography (TEE). * **First sign of VAE:** Decrease in End-Tidal $CO_2$ ($EtCO_2$) and a "mill-wheel" murmur. * **Management of VAE:** Flood the field with saline, place the patient in **Durant’s position** (Left lateral decubitus with Trendelenburg), and aspirate air via a CVP line.

Q: A severely ill patient was maintained on an infusional anesthetic agent. On the 2nd day, he started deteriorating. What is the probable culprit?

Propofol. ### Explanation The correct answer is **Propofol**. The clinical scenario describes a patient deteriorating after a prolonged infusion of an anesthetic agent, which is a classic presentation of **Propofol Infusion Syndrome (PRIS)**. **1. Why Propofol is Correct:** PRIS is a rare but often fatal complication associated with high-dose (>4 mg/kg/hr) or prolonged (>48 hours) infusions of propofol, typically in critically ill patients. The underlying mechanism involves the inhibition of mitochondrial fatty acid oxidation and the electron transport chain. This leads to a severe metabolic crisis characterized by: * Refractory metabolic acidosis * Rhabdomyolysis (leading to hyperkalemia and acute kidney injury) * Hepatomegaly and hyperlipidemia * Cardiac failure/arrhythmias (often Brugada-like ECG patterns) **2. Why Other Options are Incorrect:** * **Etomidate:** While etomidate can cause **adrenocortical suppression** (by inhibiting 11-beta-hydroxylase), it typically presents as a relative adrenal insufficiency rather than the rapid multisystem deterioration seen in PRIS. * **Opioids:** Prolonged opioid infusions (e.g., Fentanyl) primarily cause respiratory depression, ileus, or delayed emergence, but not the metabolic collapse described. * **Barbiturates:** Thiopental infusions are rarely used for maintenance due to accumulation in fat (long context-sensitive half-life), but they do not cause a specific "infusion syndrome" like propofol. **3. High-Yield Clinical Pearls for NEET-PG:** * **PRIS Trigger:** Dose >4 mg/kg/hr for >48 hours. * **Early Sign:** Unexplained metabolic acidosis or green-colored urine (due to phenols). * **Management:** Immediate discontinuation of propofol and supportive care (hemodialysis/ECMO). * **Propofol Composition:** It is an emulsion containing soybean oil and egg lecithin; it supports bacterial growth and can cause hypertriglyceridemia.

Q: Which of the following anesthetic agents is known to be hepatotoxic?

Halothane. **Explanation:** **Halothane** is the correct answer because it is uniquely associated with drug-induced liver injury, famously known as **Halothane Hepatitis**. This occurs via two mechanisms: 1. **Type I (Minor):** A transient, self-limiting rise in transaminases due to direct toxic metabolites. 2. **Type II (Major):** A rare but severe immune-mediated fulminant hepatic failure. It occurs when halothane is metabolized by Cytochrome P450 to **trifluoroacetyl chloride**, which binds to liver proteins. This creates a neo-antigen, triggering an antibody response that destroys hepatocytes. Risk factors include multiple exposures, female gender, and obesity. **Analysis of Incorrect Options:** * **Ketamine:** Primarily metabolized in the liver but is not hepatotoxic. It is known for its sympathomimetic effects (increased HR/BP) and dissociative anesthesia. * **Ether:** Historically significant but largely obsolete; it is irritating to the airways and highly flammable, but not specifically linked to hepatotoxicity. * **Nitrous Oxide:** Known for inhibiting **Vitamin B12-dependent enzymes** (methionine synthase), leading to megaloblastic anemia or subacute combined degeneration of the cord with chronic use, but it does not cause liver damage. **High-Yield Clinical Pearls for NEET-PG:** * **Metabolism:** Halothane is the most extensively metabolized volatile anesthetic (~20%), which contributes to its toxicity. In contrast, **Desflurane** is the least metabolized (0.02%). * **"Halothane Shakes":** Post-operative shivering is common with halothane. * **Arrhythmias:** Halothane sensitizes the myocardium to catecholamines, increasing the risk of arrhythmias if adrenaline is used concurrently. * **Modern Alternative:** **Isoflurane and Sevoflurane** are preferred in modern practice as they undergo minimal metabolism and lack significant hepatotoxicity.

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.

Question 1

All are true statements about malignant hyperthermia except?

Accepted Answer

Oral dantrolene is the drug of choice.

Answer

It is an autosomal dominant condition.

Answer

Total intravenous anesthesia (TIVA) is safe in malignant hyperthermia.

Answer

Malignant hyperthermia is a hypermetabolic state with elevated end-tidal CO2, tachypnea, tachycardia, masseter spasm if succinylcholine is used, and generalized muscle rigidity.

Question 2

Which of the following is true regarding post-spinal headache?

Accepted Answer

It typically improves with caffeine administration.

Answer

It does not improve when the patient is in a recumbent position.

Answer

It is more pressure-dependent than volume-dependent.

Answer

It starts immediately after the spinal procedure.

Question 3

In which patient position is venous air embolism most commonly encountered?

Accepted Answer

Sitting

Answer

Supine

Answer

Prone

Answer

Left lateral

Question 4

A patient under inhalational anesthesia suddenly develops fever, increased heart rate and BP, acidosis, and arrhythmia during surgery. What is your first step of intervention?

Accepted Answer

Dantrolene

Answer

Sodium bicarbonate

Answer

Procainamide

Answer

Antipyretics

Question 5

A patient develops the arrhythmia shown in the ECG below, intra-operatively. What is the drug of choice (DOC)?

Accepted Answer

Propranolol

Answer

Adrenaline

Answer

Hyoscine

Answer

Neostigmine

Question 6

Which of the following is NOT a complication of surgery performed in the sitting position?

Accepted Answer

Hemorrhage

Answer

Venous air embolism

Answer

Pneumocephalus

Answer

Tongue edema

Question 7

A severely ill patient was maintained on an infusional anesthetic agent. On the 2nd day, he started deteriorating. What is the probable culprit?

Accepted Answer

Propofol

Answer

Etomidate

Answer

Opioid

Answer

Barbiturate

Question 8

In all of the following conditions, hyperkalemia produced by succinylcholine is exaggerated, except?

Accepted Answer

Stroke

Answer

Spinal cord transaction

Answer

Muscle dystrophy

Answer

Trauma

Question 9

Which of the following anesthetic agents is known to be hepatotoxic?

Accepted Answer

Halothane

Answer

Ketamine

Answer

Ether

Answer

Nitrous Oxide

Question 10

What is the most common cause of death after anesthesia?

Accepted Answer

Cardiac arrest

Answer

Hypothermia

Answer

Hypotension

Answer

Atelectasis

Complications in Anesthesia — MCQs

Complications in Anesthesia — MCQs

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