Perioperative Cardiac Complications — MCQs
Which anesthetic agent is considered the least cardiotoxic?
Most sensitive method of monitoring cardiovascular ischemia in the perioperative period is -
What is the cardiac risk associated with breast surgery?
Which of the following is a risk factor for deep vein thrombosis (DVT)?
Which of the following is not used in controlling heart rate intraoperatively?
Problems which may result from hypotensive anesthesia include:
All are the Complication of CVP line except
Malignant hyperthermia is a rare complication of the use of the following anaesthetic:
Which of the following is NOT a recognized complication of massive blood transfusion?
All are used for management of hyperkalemia except?
Perioperative Cardiac Complications Indian Medical PG Practice Questions and MCQs
Question 1: Which anesthetic agent is considered the least cardiotoxic?
- A. Isoflurane
- B. Enflurane
- C. Sevoflurane (Correct Answer)
- D. Halothane
Explanation: ***Sevoflurane*** - Sevoflurane is known for its **smooth induction** and rapid recovery, making it a common choice, especially in pediatric anesthesia [3]. - It has a relatively **low pungency** and minimal cardiovascular depressant effects compared to other volatile anesthetics, contributing to its favorable cardiotoxicity profile [1], [4]. *Enflurane* - Enflurane can cause **myocardial depression** and may induce **seizures** at higher concentrations, limiting its use [1]. - Its widespread use has decreased due to concerns about its **cardiovascular effects** and potential for **renal toxicity**. *Isoflurane* - While Isoflurane is a commonly used anesthetic, it can cause **coronary steal phenomenon** in patients with coronary artery disease due to its potent vasodilatory effects. - It also causes dose-dependent **myocardial depression** and can increase heart rate, which may be detrimental in some patients [4]. *Halothane* - Halothane is known for significant **myocardial depression**, causing a decrease in cardiac output and systemic vascular resistance [2]. - It also sensitizes the myocardium to **catecholamines**, increasing the risk of arrhythmias, and is associated with **halothane hepatitis**, a rare but severe liver injury [3].
Question 2: Most sensitive method of monitoring cardiovascular ischemia in the perioperative period is -
- A. NIBP
- B. ECG
- C. Pulse oximeter
- D. TEE (Correct Answer)
Explanation: ***TEE*** - **Transesophageal echocardiography (TEE)** is the most sensitive method for detecting perioperative myocardial ischemia because it can visualize **regional wall motion abnormalities** and changes in **ventricular function** much earlier than ECG. - **Ischemia** directly impairs the contractility of the affected myocardium, leading to subtle changes in wall motion that TEE can identify. *NIBP* - **Non-invasive blood pressure (NIBP)** monitoring can detect **hemodynamic changes** (like hypotension or hypertension) that may precede or accompany ischemia. - However, these changes are **non-specific** and occur relatively late, making NIBP a less sensitive indicator of early ischemia. *ECG* - **Electrocardiography (ECG)** monitors the electrical activity of the heart and can detect **ST-segment changes** indicative of ischemia. - While useful, ECG changes may appear later than wall motion abnormalities, and **silent ischemia** can be missed if the leads are not optimally placed or if the ischemia does not produce significant electrical changes. *Pulse oximeter* - A **pulse oximeter** measures **oxygen saturation** in the peripheral blood. - It is primarily used to assess **respiratory function** and tissue oxygenation, and it does not directly monitor myocardial ischemia or cardiac function.
Question 3: What is the cardiac risk associated with breast surgery?
- A. > 10 %
- B. 1 - 5 %
- C. 5 - 10 %
- D. < 1% (Correct Answer)
Explanation: ***< 1%*** - Breast surgery is generally considered a **low-risk procedure** regarding cardiac complications. - The incidence of major adverse cardiac events (MACE) is typically very low, often reported as **less than 1%**. *1 - 5 %* - This risk range is usually associated with **intermediate-risk surgical procedures**, such as carotid endarterectomy or peripheral vascular surgery, which involve higher cardiac stress. - Breast surgery does not typically fall into this category due to its less extensive physiological impact. *5 - 10 %* - This elevated risk percentage is characteristic of **high-risk surgeries**, including major vascular procedures (e.g., aortic aneurysm repair) or organ transplantation. - Such procedures involve significant fluid shifts, blood loss, and prolonged anesthesia, increasing cardiac strain. *> 10 %* - A cardiac risk exceeding 10% is extremely high and would generally be seen only in patients with **severe pre-existing cardiac disease** undergoing emergency major surgery, or in complex, extremely high-risk procedures. - Breast surgery typically does not pose such a profound cardiac risk.
Question 4: Which of the following is a risk factor for deep vein thrombosis (DVT)?
- A. Hypertension
- B. Chronic kidney disease
- C. Hyperthyroidism
- D. Prolonged immobility (Correct Answer)
Explanation: Detailed understanding of deep vein thrombosis (DVT) and its risk factors is essential for clinical practice. **Prolonged immobility**, such as during long flights, bed rest, or surgery, significantly increases the risk of DVT due to **venous stasis** [1]. **Reduced blood flow** allows clotting factors to accumulate, promoting the formation of a thrombus. *Hypertension*, while a risk factor for **atherosclerosis** and cardiovascular disease, is **not directly a primary risk factor for DVT**. Its effects on blood vessels are generally distinct from the venous stasis and hypercoagulability mechanisms primarily involved in DVT. *Chronic kidney disease* (CKD) can lead to a **prothrombotic state** due to various factors like endothelial dysfunction and inflammation; specific conditions like Nephrotic syndrome are noted risk factors [1]. However, CKD is not as direct or strong a risk factor for DVT as immobility, and many deaths are related to coexisting medical conditions [1]. *Hyperthyroidism* can cause a **hypercoagulable state**, increasing the risk of both arterial and venous thrombosis, but it is less commonly emphasized as a primary DVT risk factor compared to prolonged immobility.
Question 5: Which of the following is not used in controlling heart rate intraoperatively?
- A. Verapamil
- B. Esmolol
- C. Propanolol/Metoprolol
- D. Procainamide (Correct Answer)
Explanation: ***Procainamide*** - While an antiarrhythmic, **procainamide** is primarily used for the treatment of various *atrial* and *ventricular arrhythmias* and *Wolff-Parkinson-White syndrome*, not for heart rate control alone. - Its mechanism involves blocking sodium channels and some potassium channels, affecting myocardial excitability and conduction. *Verapamil* - **Verapamil** is a **non-dihydropyridine calcium channel blocker** frequently used intraoperatively to **slow heart rate** by acting on the sinoatrial and atrioventricular nodes. - It is effective in treating *supraventricular tachycardias* (SVT) and controlling ventricular rate in *atrial fibrillation* or *flutter*. *Esmolol* - **Esmolol** is a **short-acting, cardioselective beta-1 adrenergic blocker** that is often administered intraoperatively due to its rapid onset and offset of action. - It is used to quickly **decrease heart rate** and blood pressure, particularly in response to surgical stress or in cases of *supraventricular tachycardia*. *Propranolol/Metoprolol* - **Propranolol** (non-selective) and **Metoprolol** (cardioselective) are **beta-adrenergic blockers** commonly used to **reduce heart rate** and myocardial oxygen demand. - They are effective in managing *tachycardia*, *hypertension*, and preventing *myocardial ischemia* during surgery.
Question 6: Problems which may result from hypotensive anesthesia include:
- A. Deep vein thrombosis
- B. Reactionary hemorrhage
- C. Retraction anemia
- D. All of the options (Correct Answer)
Explanation: ***All of the options*** - Hypotensive anesthesia is a technique used to reduce **blood pressure** during surgery, aiming to decrease **blood loss** and improve the **surgical field visibility**. - While beneficial, it carries inherent risks including **deep vein thrombosis (DVT), reactionary hemorrhage**, and complications like **retraction anemia** if not managed properly. *Deep vein thrombosis (DVT)* - While hypotension might seem to reduce the risk by lowering **blood flow velocity**, prolonged immobility and potential for **venous stasis** during any surgery, especially under hypotension, can increase DVT risk. - The combination of **endothelial dysfunction** and **hypercoagulability** often seen in surgical patients, coupled with reduced peripheral blood flow due to hypotension, can contribute to DVT formation. *Reactionary hemorrhage* - This is a common post-operative complication where bleeding restarts hours after surgery. With hypotensive anesthesia, **blood vessels** are constricted and may not be actively bleeding during the surgery. - As the patient's **blood pressure** returns to normal post-operatively, these previously undetected bleeds can manifest as significant **hemorrhage** due to the increased pressure. *Retraction anemia* - This term is less commonly used in medical literature. However, it likely refers to the complications arising from prolonged tissue retraction during surgery, which, when combined with reduced **perfusion** from hypotensive anesthesia, can lead to **tissue ischemia** or damage akin to anemia in the affected area. - The reduced **oxygen delivery** to tissues during hypotensive states, especially when further compromised by retraction, may result in localized tissue injury or contribute to systemic complications if severe or prolonged.
Question 7: 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 8: 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 9: Which of the following is NOT a recognized complication of massive blood transfusion?
- A. Hypokalemia
- B. Hypothermia
- C. Hypocalcemia
- D. Hypernatremia (Correct Answer)
Explanation: ***Hypernatremia*** - Massive transfusions, especially of packed red blood cells (PRBCs) preserved in solutions like **CPDA-1**, actually tend to cause **hyponatremia** due to the low sodium content of the transfusion products relative to plasma. - While PRBCs have some sodium, the net effect of large volumes is a dilutional effect on plasma sodium and the infusion of sodium-poor fluids, making hypernatremia an unlikely complication. *Hypokalemia* - Although stored blood products accumulate extracellular potassium (leading to hyperkalemia), **hypokalemia** can occur post-transfusion due to the rapid uptake of potassium by metabolically active cells. - This is particularly true if the patient has pre-existing conditions or is on certain medications that can shift potassium intracellularly. *Hypothermia* - Stored blood is refrigerated, and rapid infusion of large volumes of cold blood can significantly lower the patient's **core body temperature**. - **Hypothermia** can exacerbate coagulopathy and lead to cardiac arrhythmias. *Hypocalcemia* - The citrate anticoagulant used in blood products chelates calcium, reducing the amount of **ionized calcium** available in the patient's bloodstream. - Massive transfusions overwhelm the liver's ability to metabolize citrate, leading to significant **hypocalcemia**.
Question 10: All are used for management of hyperkalemia except?
- A. Insulin plus dextrose
- B. Beta 2 agonist
- C. Calcium gluconate
- D. ACE inhibitors (Correct Answer)
Explanation: ***ACE inhibitors*** - **ACE inhibitors** (Angiotensin-Converting Enzyme inhibitors) are a common cause of **hyperkalemia** because they block the production of aldosterone, which normally promotes potassium excretion [1]. - Therefore, ACE inhibitors would worsen hyperkalemia rather than treat it. *Insulin plus dextrose* - **Insulin** drives potassium into cells, thereby lowering serum potassium levels; **dextrose** is given concurrently to prevent hypoglycemia [1]. - This is a rapid and effective treatment for acute hyperkalemia, especially in emergent situations [1]. *Beta 2 agonist* - **Beta-2 adrenergic agonists** (e.g., albuterol) stimulate the sodium-potassium pump, promoting the intracellular shift of potassium. - This effect helps to decrease extracellular potassium levels, making it a viable treatment option for hyperkalemia. *Calcium gluconate* - **Calcium gluconate** does not lower serum potassium levels but stabilizes the cardiac cell membrane potential, reducing the risk of arrhythmias caused by hyperkalemia [1]. - It is often the first-line treatment in hyperkalemic emergencies with ECG changes [1].
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