Cardiovascular Anesthesia — MCQs

Cardiovascular Anesthesia Indian Medical PG Practice Questions and MCQs

Question 41: Which of the following is most cardio depressant

A. Sevoflurane
B. Halothane (Correct Answer)
C. Isoflurane
D. Desflurane

Explanation: ***Halothane*** - **Halothane** is known for causing significant **myocardial depression** by directly reducing myocardial contractility and stroke volume. - It also **sensitizes the myocardium to catecholamines**, increasing the risk of arrhythmias. *Sevoflurane* - **Sevoflurane** causes less **myocardial depression** and is often preferred in patients with compromised cardiac function. - Its effects on heart rate and blood pressure are generally moderate compared to halothane. *Isoflurane* - **Isoflurane** can cause **systemic vasodilation** and a dose-dependent decrease in blood pressure but is generally less cardio-depressant than halothane. - It maintains **cardiac output** better than halothane, sometimes increasing heart rate to compensate for vasodilation. *Desflurane* - **Desflurane** typically causes a **lesser degree of myocardial depression** and tends to preserve cardiac output. - It can, however, lead to transient increases in heart rate and blood pressure upon rapid increases in concentration due to **sympathetic stimulation**.

Question 42: Drug that does not cause cardiac depression:

A. Thiopentone
B. Ketamine
C. Propofol
D. Etomidate (Correct Answer)

Explanation: ***Etomidate*** - Etomidate is known for its **cardiovascular stability**, making it a preferred induction agent in patients with **compromised cardiac function**. - It maintains **myocardial contractility** and does not typically cause a significant drop in blood pressure. *Thiopentone* - Thiopentone causes **dose-dependent myocardial depression** and peripheral vasodilation. - This can lead to a significant **decrease in blood pressure** and cardiac output, especially in hypovolemic patients. *Propofol* - Propofol is a potent **vasodilator** and can cause significant **myocardial depression**, leading to hypotension. - Its cardiovascular effects are often more pronounced than those of other induction agents, necessitating careful titration. *Ketamine* - Ketamine causes indirect cardiovascular stimulation (due to **sympathetic nervous system activation**), but direct myocardial depression. - While it often increases heart rate and blood pressure, this is a compensatory mechanism and its direct effect on the myocardium is depressant.

Question 43: A 70-year-old male with a history of ischemic heart disease is undergoing emergency femur fracture repair. Which intraoperative complication is he at the highest risk for?

A. Cerebral embolism (Correct Answer)
B. Pulmonary edema
C. Renal failure
D. Myocardial infarction

Explanation: ***Cerebral embolism*** - Patients undergoing **orthopedic surgery**, especially for **femur fractures**, are at risk for **fat embolism syndrome**, which can lead to cerebral emboli. This risk is compounded by the pre-existing **ischemic heart disease** (IHD) which suggests underlying atherosclerosis, increasing vulnerability to embolic events overall. - The surgical manipulation of the bone marrow releases **fat globules** into the bloodstream which can travel to the brain, causing **neurological deficits** such as confusion, focal neurological signs, and even coma. *Pulmonary edema* - While possible in patients with IHD, **pulmonary edema** is typically associated with fluid overload or severe cardiac dysfunction. - Although general anesthesia and surgery can contribute to fluid shifts, the most immediate and specific complication for bone fracture repair is related to bone marrow release. *Renal failure* - **Acute renal failure** can occur post-operatively due to hypoperfusion, nephrotoxic drugs, or sepsis. - However, it's not the highest or most direct risk specifically associated with femur fracture repair in a patient with IHD compared to embolic events. *Myocardial infarction* - Patients with IHD are at an increased risk of **perioperative myocardial infarction (MI)** due to surgical stress and changes in hemodynamic parameters. - While a significant concern, the direct immediate risk from the bone manipulation during a femur fracture repair specifically points towards embolic phenomena, making cerebral embolism a slightly higher risk in this context.

Question 44: A 65-year-old male with a history of chronic heart failure is undergoing hip replacement. Which intraoperative management strategy is most appropriate for maintaining hemodynamic stability?

A. Avoiding excessive fluid administration (Correct Answer)
B. Maintaining elevated heart rate
C. Using vasodilators cautiously
D. Increasing preload moderately

Explanation: **Avoiding excessive fluid administration** - Patients with **chronic heart failure** are prone to **fluid overload**, which can lead to pulmonary edema and worsened cardiac function due to increased **intravascular volume** and **cardiac preload**. - **Careful fluid management** minimizes the risk of perioperative cardiac decompensation and ensures hemodynamic stability. *Maintaining elevated heart rate* - An **elevated heart rate** in a patient with heart failure can drastically increase myocardial oxygen demand and reduce diastolic filling time, potentially leading to **myocardial ischemia** and **cardiac decompensation**. - Maintaining a **normal or slightly reduced heart rate** is generally preferred to optimize cardiac output and minimize cardiac stress. *Using vasodilators cautiously* - While vasodilators can reduce **afterload** and improve cardiac output, their use must be extremely cautious in hip replacement surgery due to potential for significant **hypotension** and **reduced organ perfusion**. - The primary concern during surgery is often blood loss and fluid shifts, which already predispose to hypotension, making aggressive vasodilation risky. *Increasing preload moderately* - Moderately increasing preload can be beneficial in some patients, but in those with **chronic heart failure**, even moderate increases can quickly lead to **pulmonary congestion** and cardiac decompensation. - The failing heart has a limited ability to handle increased volume, meaning that optimizing preload typically involves avoiding both hypovolemia and hypervolemia through **precise fluid titration**.

Question 45: A 50-year-old female with a history of coronary artery disease is undergoing an elective laparoscopic cholecystectomy. Which anesthetic agent is preferred to minimize myocardial oxygen consumption?

A. Desflurane
B. Nitrous oxide
C. Sevoflurane (Correct Answer)
D. Isoflurane

Explanation: ***Sevoflurane*** - **Sevoflurane** is preferred due to its ability to maintain **hemodynamic stability** and minimize **myocardial oxygen consumption**, which is crucial in patients with **coronary artery disease (CAD)**. - It has a relatively **low pungency**, making it suitable for inhalation induction and reducing airway irritation that could trigger adverse cardiac events. *Desflurane* - **Desflurane** is associated with a **more rapid increase in heart rate and blood pressure** upon induction and changes in anesthetic depth, which increases **myocardial oxygen demand** and can be detrimental in CAD patients. - Its **pungent odor** can cause airway irritation, coughing, and laryngospasm, further stressing the cardiovascular system. *Nitrous oxide* - **Nitrous oxide (N2O)** should be used with caution or avoided in CAD patients because it can cause **vasoconstriction** and potentially increase **pulmonary vascular resistance**, thus increasing cardiac workload. - It also has a **low potency**, requiring co-administration with other agents, and can expand air-filled spaces, posing risks during laparoscopic surgery. *Isoflurane* - While **isoflurane** has cardioprotective properties, it can cause **coronary steal phenomenon** at deeper anesthetic depths, where blood flow is diverted from ischemic areas to non-ischemic areas, potentially worsening ischemia. - Its **stronger pungent odor** compared to sevoflurane can lead to airway irritation and coughing, which is undesirable in patients with compromised cardiac function.

Question 46: A 50-year-old female with a history of mitral stenosis is scheduled for an elective cholecystectomy. Which intraoperative monitoring is most appropriate for this patient?

A. Central venous pressure monitoring
B. Continuous ECG monitoring
C. Pulmonary artery catheter
D. Invasive arterial blood pressure monitoring (Correct Answer)

Explanation: ***Invasive arterial blood pressure monitoring*** - This provides **beat-to-beat blood pressure readings**, which are crucial for immediate detection and management of hemodynamic changes during surgery in a patient with significant cardiac disease like **mitral stenosis**. - Mitral stenosis patients are prone to acute hemodynamic instability, and **invasive arterial monitoring** allows continuous assessment of systemic vascular resistance and cardiac output indirectly, guiding anesthetic management. *Pulmonary artery catheter* - While it provides detailed information on **cardiac output**, **pulmonary artery pressures**, and **pulmonary capillary wedge pressure**, its use is typically reserved for more complex cases or patients with severe ventricular dysfunction or pulmonary hypertension, and is associated with some risks. - For an elective cholecystectomy in a patient with stable mitral stenosis, the risks likely outweigh the benefits compared to less invasive but still highly informative monitoring. *Central venous pressure monitoring* - **CVP monitoring** primarily reflects **right atrial pressure** and intravascular volume status, which is less specific for assessing the hemodynamic impact of mitral stenosis on left heart function. - While useful for guiding fluid management, it does not provide direct, continuous feedback on systemic blood pressure changes, which are critically important in a patient with mitral stenosis undergoing surgery. *Continuous ECG monitoring* - **Continuous ECG monitoring** is standard for all surgical patients to detect arrhythmias and ischemia, but it does not provide information on the **hemodynamic consequences** of these events or the overall circulatory status. - While essential, it is insufficient on its own for a patient with mitral stenosis, who requires more direct assessment of **blood pressure** and cardiac function to manage potential hemodynamic instability.

Question 47: A 65-year-old male with a history of hypertension, coronary artery disease, and chronic kidney disease is scheduled for aortic aneurysm repair. Evaluate the potential complications and select the best intraoperative management strategy.

A. Aggressive fluid administration to maintain blood pressure
B. Controlled hypotension with vasodilators to reduce blood loss (Correct Answer)
C. Use of high-dose opioids to minimize stress response
D. Intraoperative diuresis to prevent fluid overload

Explanation: **Controlled hypotension with vasodilators to reduce blood loss** - This strategy helps **minimize blood loss** during aortic aneurysm repair, which is crucial in patients with comorbidities like **coronary artery disease** and **chronic kidney disease**, reducing the need for transfusions and their associated risks. - **Controlled hypotension** reduces **cardiac afterload** and **myocardial oxygen demand**, which is beneficial for a patient with **hypertension** and **coronary artery disease**. *Aggressive fluid administration to maintain blood pressure* - **Aggressive fluid administration** can lead to **fluid overload**, particularly in a patient with **chronic kidney disease** and **cardiac comorbidities**, exacerbating heart failure or pulmonary edema. - While maintaining blood pressure is important, **aggressive fluid administration** alone without careful monitoring can cause more complications than benefits in this high-risk patient. *Use of high-dose opioids to minimize stress response* - High-dose opioids can cause significant **respiratory depression** and **hemodynamic instability**, which are particularly risky in a patient with **cardiovascular disease** and **chronic kidney disease**. - While opioids are part of anesthesia, **high-dose strategies** should be balanced against their potential adverse effects on ventilation and circulation. *Intraoperative diuresis to prevent fluid overload* - **Intraoperative diuresis** can worsen **hypovolemia** and **renal perfusion**, which is detrimental in a patient with **chronic kidney disease** facing a major vascular procedure, potentially leading to acute kidney injury. - Diuresis should only be considered after adequate fluid resuscitation and only if true fluid overload is confirmed, not as a primary preventive measure against it during a surgery with significant blood loss potential.

Question 48: A 70-year-old male with a history of diabetes is undergoing surgery. During the operation, he develops signs of myocardial ischemia. Which intraoperative management step is the most appropriate?

A. Increase the rate of intravenous fluids
B. Administer nitroglycerin (Correct Answer)
C. Administer beta-blockers
D. Increase the depth of anesthesia

Explanation: ***Administer nitroglycerin*** - **Nitroglycerin** causes **vasodilation**, which can improve blood flow to the heart and reduce myocardial oxygen demand, effectively treating **myocardial ischemia**. - It is particularly useful in an acute setting to rapidly alleviate symptoms and prevent further damage. *Increase the rate of intravenous fluids* - Increasing intravenous fluids could lead to **fluid overload**, potentially worsening cardiac function in a patient with myocardial ischemia, especially if cardiac output is already compromised. - This intervention would be more appropriate for **hypovolemia rather than ischemia**. *Administer beta-blockers* - While beta-blockers reduce heart rate and contractility, which are beneficial for myocardial oxygen demand, they can also cause **hypotension** or **bradycardia**, which could exacerbate ischemia or compromise tissue perfusion if not carefully titrated. - Their full effect is not immediate, making them less suitable for **acute intraoperative management** compared to nitroglycerin. *Increase the depth of anesthesia* - Increasing anesthetic depth generally leads to **hypotension** and **decreased cardiac output**, which could further compromise coronary perfusion and worsen myocardial ischemia. - The goal during ischemia is to improve cardiac function and oxygen supply, not to suppress it further.

Question 49: Which one of the following agents sensitizes the myocardium to catecholamines?

A. Isoflurane
B. Ether
C. Halothane (Correct Answer)
D. Propofol

Explanation: ***Halothane*** - **Halothane** sensitizes the myocardium to the arrhythmogenic effects of **catecholamines**, leading to an increased risk of ventricular arrhythmias, especially in the presence of exogenous adrenaline. - This sensitization occurs due to its effect on myocardial **calcium ion** regulation and increased automaticity in cardiac pacemaker cells. *Isoflurane* - **Isoflurane** causes minimal sensitization of the myocardium to catecholamines compared to halothane. - It maintains **cardiac output** with a dose-dependent decrease in systemic vascular resistance. *Ether* - **Diethylether** historically caused sympathetic stimulation, which could mask some depressant effects but did not primarily sensitize the myocardium to arrhythmias from exogenous catecholamines. - Its use has largely been replaced due to its flammability and slower induction/recovery. *Propofol* - **Propofol** generally causes myocardial depression and vasodilation, but it does **not sensitize** the myocardium to catecholamines in a clinically significant way that increases arrhythmogenic risk. - It often leads to a decrease in **blood pressure** and heart rate.

Question 50: All of the following cause myocardial depression except:

A. Halothane
B. Thiopentone
C. Etomidate (Correct Answer)
D. Ketamine

Explanation: ***Etomidate*** - **Etomidate** is known for its **hemodynamic stability** and minimal effect on myocardial contractility, making it a suitable induction agent for patients with cardiovascular compromise. - While it can cause some decrease in systemic vascular resistance, it maintains **cardiac output** much better than other agents listed. *Halothane* - **Halothane** is a potent volatile anesthetic that directly depresses **myocardial contractility** and reduces cardiac output. - It sensitizes the myocardium to **catecholamines**, increasing the risk of arrhythmias. *Thiopentone* - **Thiopentone** (thiopental) is a barbiturate that causes significant **dose-dependent myocardial depression** and systemic vasodilation. - This can lead to a substantial decrease in **blood pressure** and cardiac output, especially with rapid administration. *Ketamine* - Although ketamine often causes an increase in heart rate and blood pressure due to **sympathetic stimulation**, it can also have a direct **myocardial depressant effect** when the sympathetic nervous system is exhausted or blocked. - Its indirect stimulant effects *can mask* a direct negative inotropic effect on the myocardium.

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