Complications in Anesthesia — MCQs
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During cesarean section under general endotracheal anaesthesia, venous air embolism
A 10-year old child is undergoing squint surgery. He suddenly developed increased heart rate, arrhythmia, high fever, metabolic and respiratory acidosis on arterial blood gases and elevation of end tidal CO2. Which of the following would be the first agent of choice in the management of this condition?
A patient presents with malignant hyperthermia and metabolic acidosis. Immediate treatment should be started with:
What is the first line of management in malignant hyperthermia?
All are the Complication of CVP line except
55-year-old female, a known case of thyrotoxicosis under control, posted for abdominoperineal resection. During surgery, there was sudden drop in B.P. and end-tidal CO2 decreased from 40 to 10 mmHg. On auscultation, there was a mill wheel murmur. What is the diagnosis?
Most common cause of metabolic acidosis in anesthesia is:
Malignant hyperthermia is a rare complication of the use of the following anaesthetic:
What is the earliest sign of malignant hyperthermia?
Which is the MOST accurate statement regarding post-dural anesthetic headache:
Complications in Anesthesia Indian Medical PG Practice Questions and MCQs
Question 221: During cesarean section under general endotracheal anaesthesia, venous air embolism
- A. Induces severe hypertension
- B. Is associated with decreased end-tidal CO2 (Correct Answer)
- C. Should be treated with nitrous oxide
- D. Is associated with high end-tidal CO2
Explanation: ***Is associated with decreased end-tidal CO2*** - Venous air embolism causes **pulmonary artery obstruction**, leading to ventilation-perfusion mismatch and decreased blood flow to the lungs. - This reduced pulmonary blood flow results in a significant **decrease in expired CO2**, as less CO2 is delivered to the alveoli for exhalation. *Induces severe hypertension* - Venous air embolism typically causes **hypotension** due to reduced cardiac output and right ventricular failure, not hypertension. - Direct effects of air in the circulation include **vasodilation** and myocardial depression, contributing to a drop in blood pressure. *Should be treated with nitrous oxide* - **Nitrous oxide** should be avoided in cases of venous air embolism as it expands gas-filled spaces, potentially increasing the size of the air embolus and worsening patient outcomes. - Treatment involves 100% oxygen, Trendelenburg position, left lateral decubitus, and aspiration of air from the right atrium, not the administration of additional gas. *Is associated with high end-tidal CO2* - A high end-tidal CO2 would indicate improved ventilation or perfusion, which is contrary to the effects of a venous air embolism that **reduces pulmonary blood flow** and thus CO2 exchange. - The hallmark respiratory sign of venous air embolism is a **sudden profound decrease in end-tidal CO2** due to arterial obstruction.
Question 222: A 10-year old child is undergoing squint surgery. He suddenly developed increased heart rate, arrhythmia, high fever, metabolic and respiratory acidosis on arterial blood gases and elevation of end tidal CO2. Which of the following would be the first agent of choice in the management of this condition?
- A. Procainamide
- B. Sodium bicarbonate
- C. Paracetamol
- D. Dantrolene (Correct Answer)
Explanation: ***Dantrolene*** - The constellation of **tachycardia**, **arrhythmia**, **high fever**, **acidosis**, and **elevated end-tidal CO2** during surgery strongly points to **malignant hyperthermia (MH)**. - **Dantrolene** is the specific and most effective direct-acting skeletal muscle relaxant that treats MH by reducing intracellular calcium release. *Procainamide* - **Procainamide** is an **antiarrhythmic drug** that could be used to manage some arrhythmias, but it does not address the underlying pathophysiology of malignant hyperthermia. - While arrhythmias are a symptom of MH, simply treating the arrhythmia without addressing the hypermetabolic state is insufficient and potentially dangerous. *Sodium bicarbonate* - **Sodium bicarbonate** is used to treat **metabolic acidosis**, which is a sign of MH, but it does not treat the root cause of the acidosis, which is the massive release of calcium in muscle cells. - While it can temporize the acid-base balance, it is not the primary treatment for the overall syndrome. *Paracetamol* - **Paracetamol** is an **antipyretic** and **analgesic** and would be completely ineffective in managing the rapid and severe temperature elevation seen in malignant hyperthermia. - Its mechanism of action does not address the massive heat production and hypermetabolism characteristic of MH.
Question 223: A patient presents with malignant hyperthermia and metabolic acidosis. Immediate treatment should be started with:
- A. Intravenous fluids
- B. Sodium bicarbonate
- C. Paracetamol
- D. Intravenous Dantrolene (Correct Answer)
Explanation: ***Intravenous Dantrolene*** - **Dantrolene** is the specific and primary treatment for **malignant hyperthermia** as it acts directly on the **ryanodine receptor** to inhibit calcium release from the sarcoplasmic reticulum, relaxing skeletal muscle. - Its prompt administration is crucial in reversing the life-threatening metabolic and physiological derangements associated with this condition, including **hyperthermia** and **metabolic acidosis**. *Intravenous fluids* - While **intravenous fluids** are important for maintaining hydration and supporting renal function in patients with **malignant hyperthermia**, they are a supportive measure, not the definitive treatment. - They primarily address complications like **dehydration** and **rhabdomyolysis**, but do not directly treat the underlying pathophysiology of excessive calcium release. *Sodium bicarbonate* - **Sodium bicarbonate** may be used to correct severe **metabolic acidosis**, which can be a consequence of **malignant hyperthermia**. - However, treating the acidosis without addressing the primary cause (malignant hyperthermia) by administering dantrolene is insufficient and will not stop the progression of the syndrome. *Paracetamol* - **Paracetamol (acetaminophen)** is an antipyretic often used for fever reduction, but it is entirely ineffective in treating the rapid and severe hyperthermia of **malignant hyperthermia**. - The temperature dysregulation in malignant hyperthermia is caused by uncontrolled muscle metabolism, not a response to typical antipyretics, and thus paracetamol would provide no therapeutic benefit.
Question 224: What is the first line of management in malignant hyperthermia?
- A. Institute cooling
- B. IV dantrolene 2.5 mg/kg
- C. Administer bicarbonate
- D. Discontinue triggering agent (Correct Answer)
Explanation: ***Discontinue triggering agent*** - The immediate and most crucial first step is to **discontinue** all **halogenated inhalational anesthetics** and **succinylcholine**, as these are the agents that trigger malignant hyperthermia. - Failure to remove the triggering agents will lead to continued progression of the hypermetabolic state, making other interventions less effective. *Institute cooling* - While **cooling measures** are essential for managing the **hyperthermia** and are implemented early, they are secondary to discontinuing the causative agent. - Cooling alone will not cease the underlying muscle hypermetabolism and calcium release without removing the triggering substance. *IV dantrolene 2.5 mg/kg* - **Dantrolene** is the specific antidote for malignant hyperthermia, directly interfering with calcium release from the sarcoplasmic reticulum, and should be administered as soon as possible after suspicion. - However, the very first step is to stop the continuous exposure to the triggering agents that are causing the condition. *Administer bicarbonate* - **Bicarbonate** is used to manage the **metabolic acidosis** that develops in malignant hyperthermia due to excessive CO2 production and lactic acid. - This is a supportive measure addressing a consequence of the condition, not the primary intervention to halt the hypermetabolic crisis itself.
Question 225: All are the Complication of CVP line except
- A. Haemothorax
- B. Airway injury (Correct Answer)
- C. Air embolism
- D. Septicemia
Explanation: ***Airway injury*** - While central venous catheterization can cause various complications, direct **airway injury** (e.g., tracheal puncture) is extremely rare and not a typical complication of the procedure itself as the insertion sites are generally not near the major airways. - Complications usually involve vascular, pleural, or infectious issues rather than direct damage to the respiratory tree. *Haemothorax* - **Haemothorax** can occur if the subclavian or internal jugular vein is punctured and the needle or catheter inadvertently punctures an adjacent artery (e.g., subclavian artery), leading to bleeding into the pleural space. - This complication presents with respiratory distress and signs of hypovolemia as blood accumulates in the thoracic cavity. *Air embolism* - **Air embolism** is a serious complication, especially during insertion or removal of a CVP line, if the catheter lumen is exposed to air and negative intrathoracic pressure sucks air into the venous system. - It can lead to sudden cardiorespiratory collapse and is a recognized risk of CVP placement. *Septicemia* - **Septicemia** (or central line-associated bloodstream infection, CLABSI) is a common and serious complication, particularly with prolonged catheter dwelling times, poor aseptic technique, or inadequate site care. - Bacteria can colonize the catheter surface and enter the bloodstream, leading to systemic infection.
Question 226: 55-year-old female, a known case of thyrotoxicosis under control, posted for abdominoperineal resection. During surgery, there was sudden drop in B.P. and end-tidal CO2 decreased from 40 to 10 mmHg. On auscultation, there was a mill wheel murmur. What is the diagnosis?
- A. Hypoxia
- B. Thyroid storm
- C. Bleeding
- D. Air embolism (Correct Answer)
Explanation: ***Air embolism*** - A sudden drop in **blood pressure**, decreased **end-tidal CO2**, and a **mill wheel murmur** (a churning sound heard over the precordium) are classical signs of an **air embolism**. - Air entering the vascular system, particularly the right side of the heart, obstructs blood flow and gas exchange. *Hypoxia* - While hypoxia can lead to a drop in blood pressure and changes in end-tidal CO2, it typically does not cause a **mill wheel murmur**. - Hypoxia would usually manifest with signs of inadequate oxygenation, such as **cyanosis** or desaturation, which are not mentioned here as the primary finding. *Thyroid storm* - Thyroid storm is characterized by a rapid onset of **hypermetabolism**, including fever, tachycardia, hypertension (initially), and altered mental status. - Although it can cause cardiovascular collapse, the specific combination of a sudden drop in **end-tidal CO2** and a **mill wheel murmur** is not characteristic of thyroid storm. *Bleeding* - Significant bleeding would cause a drop in **blood pressure** and an increase in **heart rate** but typically leads to an increase in **end-tidal CO2** due to compensatory hyperventilation or metabolic acidosis. - A **mill wheel murmur** is not a feature of hypovolemia due to bleeding.
Question 227: Most common cause of metabolic acidosis in anesthesia is:
- A. Hypotension (Correct Answer)
- B. Renal failure
- C. Hypoventilation
- D. Ketoacidosis
Explanation: ***Hypotension*** - **Hypotension** leads to **tissue hypoperfusion** and **anaerobic metabolism**, resulting in the production and accumulation of **lactic acid**. - This increased lactic acid significantly contributes to **metabolic acidosis**, making it a common cause in anesthetic settings due to surgical stress and fluid shifts. *Renal failure* - While **renal failure** can cause **metabolic acidosis** due to impaired acid excretion, it is not the most common acute cause in the perioperative setting among otherwise healthy individuals undergoing anesthesia. - Its onset is typically more chronic, and its presentation during anesthesia would usually be an exacerbation of pre-existing disease rather than a primary acute cause. *Hypoventilation* - **Hypoventilation** primarily causes **respiratory acidosis** due to the retention of carbon dioxide, not metabolic acidosis. - Although it can lead to hypoxia in severe cases, the immediate and direct effect on acid-base balance is an increase in **PCO2**. *Ketoacidosis* - **Ketoacidosis** (e.g., diabetic ketoacidosis) is characterized by the overproduction of **ketone bodies**, leading to metabolic acidosis. - While severe, it's typically associated with specific underlying conditions like uncontrolled diabetes and is not the most common cause of acidosis during routine anesthesia in patients without pre-existing metabolic disorders.
Question 228: Malignant hyperthermia is a rare complication of the use of the following anaesthetic:
- A. Thiopentone sodium
- B. Halothane (Correct Answer)
- C. Ether
- D. Ketamine
Explanation: **Halothane** - **Halothane** is a potent volatile anesthetic and a classic trigger for **malignant hyperthermia** due to its effect on ryanodine receptors, leading to excessive calcium release from the sarcoplasmic reticulum. - While its use has declined, it remains a critical example of an anesthetic agent known to induce this life-threatening genetic disorder. *Thiopentone Sodium* - **Thiopentone sodium** is an intravenous barbiturate anesthetic and is **not associated** with triggering malignant hyperthermia. - It is often used for induction of anesthesia and has a different mechanism of action involving GABA receptors. *Ether* - **Diethyl ether** was one of the earliest general anesthetics but is **not a trigger** for malignant hyperthermia. - Its use has largely been discontinued due to its flammability and adverse side effects, but it doesn't cause MH. *Ketamine* - **Ketamine** is a dissociative anesthetic that acts as an NMDA receptor antagonist and is **not a trigger** for malignant hyperthermia. - It is often used for its analgesic and sedative properties and is considered safe in patients susceptible to MH.
Question 229: What is the earliest sign of malignant hyperthermia?
- A. Elevated end tidal carbon dioxide is an early sign (Correct Answer)
- B. Hyperkalemia and myoglobinuria
- C. Masseter muscle rigidity after succinylcholine
- D. Tachycardia and arrhythmias
Explanation: ***Elevated end tidal carbon dioxide is an early sign*** - An abrupt and unexplained **increase in end-tidal carbon dioxide (ETCO2)** is often the *first and most sensitive indicator* of malignant hyperthermia during anesthesia. - This rise reflects the excessive **CO2 production** due to uncontrolled muscle metabolism before a significant temperature increase is observed. *Dantrolene sodium is the drug of choice* - While **dantrolene sodium** is indeed the definitive treatment for malignant hyperthermia, it is *not an early sign* of the condition. - Administration of dantrolene is initiated *after* the signs and symptoms, such as elevated ETCO2, become apparent. *Isoflurane is an absolute contraindication* - **Volatile anesthetic agents** like **isoflurane** are known triggers for malignant hyperthermia in susceptible individuals. - Therefore, using isoflurane in a patient with a history of or susceptibility to MH is indeed contraindicated, but this statement describes a *trigger* or *preventative measure*, not an early sign. *Characterized by muscle rigidity, hyperthermia, and metabolic acidosis* - **Muscle rigidity**, **hyperthermia**, and **metabolic acidosis** are *later and more prominent signs* of malignant hyperthermia as the uncontrolled muscle contraction and metabolism progress. - They represent the more advanced stages of the syndrome and typically follow the initial rise in ETCO2.
Question 230: Which is the MOST accurate statement regarding post-dural anesthetic headache:
- A. Headache worsens with upright posture
- B. Blood patch is the first line of treatment
- C. Occurs due to low CSF pressure (Correct Answer)
- D. Increased incidence with early mobilization of patient
Explanation: ***Occurs due to low CSF pressure*** - Post-dural puncture headache (PDPH) results from continued leakage of **cerebrospinal fluid (CSF)** through the dural tear, leading to reduced intracranial pressure. - This **low CSF pressure** causes distension of pain-sensitive intracranial structures, particularly when the patient is upright. *Headache worsens with upright posture* - While the headache typically **worsens with upright posture** and improves when supine, this is a symptom rather than the underlying mechanism or the most accurate statement describing the cause. - The positional nature of the headache is a direct consequence of the **low CSF pressure**. *Blood patch is the first line of treatment* - An **epidural blood patch** is a highly effective treatment for PDPH, but it is typically reserved for severe or persistent cases that do not respond to conservative measures. - **Conservative treatment** (e.g., bed rest, hydration, analgesics, caffeine) is usually the first line, especially for mild symptoms. *Increased incidence with early mobilization of patient* - **Early mobilization** does not directly increase the incidence of PDPH. The primary risk factor is the size and type of the dural puncture. - However, early mobilization can exacerbate the symptoms of an existing PDPH due to the gravitational effect on **CSF pressure**.
Practice by Chapter
Adverse Drug Reactions
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Anaphylaxis and Allergic Reactions
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Malignant Hyperthermia
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Local Anesthetic Toxicity
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Perioperative Cardiac Complications
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Pulmonary Complications
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Awareness Under General Anesthesia
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Neurological Complications
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Postoperative Visual Loss
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Perioperative Renal Dysfunction
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Transfusion-Related Complications
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Risk Management and Prevention
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