Anesthesia for Cardiac Catheterization — MCQs
A cardiovascular parameter helpful in diagnosis of anaphylaxis during anaesthesia:
Most sensitive method of monitoring cardiovascular ischemia in the perioperative period is -
Infants require which of the following regarding anesthetic agents?
Problems which may result from hypotensive anesthesia include:
Which inhalational agent has the least MAC?
Catheter ablation for supraventricular tachycardia (SVT) is most commonly performed under which type of anesthesia?
Which of the following drugs produces dissociative anesthesia?
Early and reliable indication of air embolism during anaesthesia can be obtained by continuous monitoring of:
A hospital is designing a protocol for anesthesia services in the interventional radiology suite. Cases include hepatic chemoembolization, biliary interventions, and vascular procedures. Which combination of factors makes general anesthesia more appropriate than conscious sedation?
A radiation oncology department is planning to start providing anesthesia for pediatric patients undergoing radiotherapy. Which is the most critical infrastructure requirement specific to this non-OR anesthesia location?
Anesthesia for Cardiac Catheterization Indian Medical PG Practice Questions and MCQs
Question 1: A cardiovascular parameter helpful in diagnosis of anaphylaxis during anaesthesia:
- A. Bradycardia
- B. Dysrhythmia
- C. Increased peripheral vascular resistance
- D. Hypotension (Correct Answer)
Explanation: ***Hypotension*** - **Hypotension** is a hallmark cardiovascular sign of anaphylaxis, occurring due to widespread **vasodilation** and increased vascular permeability. - This symptom is often profound and unresponsive to initial fluid resuscitation due to the ongoing systemic release of inflammatory mediators. *Bradycardia* - While bradycardia can occur in some rare cases of anaphylaxis (e.g., **vasovagal response**), **tachycardia** is the more common cardiac response due to compensatory mechanisms. - It is not a primary or consistent indicator of anaphylaxis, making it less helpful for diagnosis in this context. *Dysrhythmia* - **Dysrhythmias** can occur during anaphylaxis due to myocardial ischemia or electrolyte imbalances, but they are not a direct or consistent diagnostic feature. - Their presence often reflects severe compromise or co-existing conditions rather than being a primary anaphylactic sign. *Increased peripheral vascular resistance* - Anaphylaxis is characterized by a significant **decrease in peripheral vascular resistance** due to mast cell and basophil degranulation releasing vasodilatory mediators like histamine. - Therefore, an increase in peripheral vascular resistance would contradict the pathophysiology of anaphylaxis.
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: Infants require which of the following regarding anesthetic agents?
- A. Equal amount as in adults
- B. Least amount of anaesthetic agent
- C. Higher amount of anaesthetic agent (Correct Answer)
- D. None of the options
Explanation: ***Higher amount of anaesthetic agent*** - Infants generally have a **larger volume of distribution** for many drugs due to a higher proportion of total body water and lower fat content, necessitating higher doses per kilogram. - Their **metabolic pathways** and **organ function** (especially hepatic and renal) are immature, which can affect clearance and drug half-life, but often the initial dosing might be higher due to distribution differences. *Equal amount as in adults* - This is incorrect as infants have significant physiological differences compared to adults, particularly in **drug distribution**, **metabolism**, and **excretion**. - Dosing anesthetics based on adult equivalents would likely lead to **underdosing** or **overdosing** due to these differences. *Least amount of anaesthetic agent* - While some medications may require lower doses in neonates due to immature metabolic pathways, many anesthetic agents, particularly those with a high volume of distribution, may require **higher doses per kilogram** to achieve the desired effect. - The concept of "least amount" is overly simplistic and does not account for the **pharmacokinetic differences** in infants. *None of the options* - This is incorrect because one of the provided options accurately reflects the general requirement for anesthetic agents in infants.
Question 4: 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 5: Which inhalational agent has the least MAC?
- A. Halothane (Correct Answer)
- B. Xenon
- C. Sevoflurane
- D. Isoflurane
Explanation: ***Halothane*** - **Halothane** has a **MAC** of approximately **0.75%**, which is among the lowest for commonly used volatile anesthetics. - A lower **MAC** indicates a higher potency, meaning a lower concentration is needed to achieve anesthetic effect. *Xenon* - **Xenon** has a **MAC** of approximately **71%**, making it one of the least potent inhalational agents. - It is an inert gas with unique anesthetic properties, but its high **MAC** is a key characteristic. *Sevoflurane* - **Sevoflurane** has a **MAC** of approximately **2.0%**, which is higher than halothane. - It is known for its rapid onset and offset due to its low blood solubility. *Isoflurane* - **Isoflurane** has a **MAC** of approximately **1.15%**, which is higher than halothane. - It is often favored for its cardiovascular stability and relatively low metabolism.
Question 6: Catheter ablation for supraventricular tachycardia (SVT) is most commonly performed under which type of anesthesia?
- A. Local anaesthesia (Correct Answer)
- B. Spinal anaesthesia
- C. No anaesthesia required
- D. General anaesthesia
Explanation: ***Local anaesthesia*** - Catheter ablation for SVT is most commonly performed with **local anaesthesia** at the access site (e.g., groin for femoral vein access) and **conscious sedation**. - This approach allows the patient to remain awake and cooperative, which is crucial for monitoring symptoms and for performing maneuvers that help identify the arrhythmogenic focus. *General anaesthesia* - While general anaesthesia can be used, it is **less common** for routine SVT ablation due to potential effects on electrophysiological properties and patient cooperation. - It may be considered for pediatric patients, highly anxious patients, or complex cases requiring precise immobility. *Spinal anaesthesia* - **Spinal anaesthesia** is a regional technique that numbs the lower body and is typically used for surgical procedures below the waist, such as orthopedic or obstetric surgeries. - It is **not suitable** for catheter ablation of the heart, which is a procedure involving vascular access and manipulations within the chest cavity. *No anaesthesia required* - Catheter ablation is an **invasive procedure** involving the insertion of catheters into blood vessels and their advancement into the heart. - Performing this procedure without any form of anaesthesia would cause **significant pain and discomfort** to the patient and is not clinically acceptable.
Question 7: Which of the following drugs produces dissociative anesthesia?
- A. Ketamine (Correct Answer)
- B. Propofol
- C. Thiopentone
- D. Enflurane
Explanation: ***Ketamine*** - **Ketamine** is a **dissociative anesthetic** that causes a trance-like state characterized by profound analgesia, amnesia, and catatonia, with the patient appearing to be awake but unresponsive. - It works by antagonizing the **NMDA receptor**, leading to a functional dissociation between the limbic and cortical systems. *Propofol* - **Propofol** is a short-acting intravenous anesthetic that produces a rapid loss of consciousness and has sedative-hypnotic properties. - It functions primarily by enhancing the activity of the **GABA-A receptor**, leading to central nervous system depression, not dissociation. *Thiopentone* - **Thiopentone** (Thiopental) is a barbiturate that induces rapid anesthesia and is used for induction and short procedures. - Its mechanism involves potentiation of the **GABA-A receptor**, causing global central nervous system depression without dissociative effects. *Enflurane* - **Enflurane** is an inhaled halogenated ether anesthetic that provides excellent muscle relaxation and analgesia. - It primarily acts by enhancing **GABAergic inhibition** and inhibiting excitatory neurotransmission, producing general anesthesia rather than a dissociative state.
Question 8: Early and reliable indication of air embolism during anaesthesia can be obtained by continuous monitoring of:
- A. Oxygen saturation
- B. End Tidal CO2 (Correct Answer)
- C. ECG
- D. Blood pressure
Explanation: ***End Tidal CO2*** - A sudden and unexplained decrease in **End Tidal CO2 (EtCO2)** is often the first sign of an air embolism. - This occurs because air in the pulmonary circulation obstructs blood flow, leading to reduced CO2 delivery to the lungs. *Oxygen saturation* - **Oxygen saturation** changes are typically a later sign of air embolism, as significant pulmonary impairment or right-to-left shunting must occur before a drop is detectable. - A decrease in saturation indicates a more advanced and potentially severe embolism. *ECG* - **ECG changes**, such as arrhythmias or signs of right heart strain, are usually late and non-specific indicators of air embolism. - These changes reflect the cardiovascular consequences of the embolism rather than its initial event. *Blood pressure* - A drop in **blood pressure** is a late and often profound sign of an air embolism, reflecting significant cardiovascular compromise. - Early detection methods precede observable changes in systemic blood pressure.
Question 9: A hospital is designing a protocol for anesthesia services in the interventional radiology suite. Cases include hepatic chemoembolization, biliary interventions, and vascular procedures. Which combination of factors makes general anesthesia more appropriate than conscious sedation?
- A. Expected moderate pain, advanced age, and multiple comorbidities
- B. Patient anxiety, lack of IV access, and obesity
- C. Duration >90 minutes, prone positioning, and need for breath-holding (Correct Answer)
- D. Contrast allergy, renal dysfunction, and coagulopathy
Explanation: ***Duration >90 minutes, prone positioning, and need for breath-holding*** - Prolonged procedures and **prone positioning** carry a high risk of **airway obstruction** and restricted access to the patient, making a secured airway via **general anesthesia** necessary. - Precise imaging during vascular or biliary interventions often requires **controlled apnea** (breath-holding), which is only reliably achieved through **neuromuscular blockade** and mechanical ventilation. *Expected moderate pain, advanced age, and multiple comorbidities* - **Moderate pain** can often be managed with **monitored anesthesia care (MAC)** or regional techniques rather than requiring full general anesthesia. - **Advanced age** and **comorbidities** represent increased perioperative risk, but they are not specific indications for general anesthesia; in fact, avoiding GA may be preferred in certain fragile patients. *Patient anxiety, lack of IV access, and obesity* - While **obesity** increases the risk of airway compromise, it does not mandate general anesthesia unless the specific procedural requirements or patient anatomy make **conscious sedation** unsafe. - **Anxiety** is typically manageable with appropriate **anxiolytic sedation**, and **IV access** is a fundamental requirement for both sedation and general anesthesia. *Contrast allergy, renal dysfunction, and coagulopathy* - These factors are related to **radiological risk** and procedural safety rather than the choice of anesthetic technique. - **Coagulopathy** is a contraindication for certain **regional anesthesia** techniques but does not specifically dictate a shift from sedation to **general anesthesia**.
Question 10: A radiation oncology department is planning to start providing anesthesia for pediatric patients undergoing radiotherapy. Which is the most critical infrastructure requirement specific to this non-OR anesthesia location?
- A. Temperature regulation system for hypothermia prevention
- B. Remote monitoring system with radiation shielding for anesthesiologist (Correct Answer)
- C. Difficult airway cart with video laryngoscope
- D. MRI-compatible anesthesia machine
Explanation: ***Remote monitoring system with radiation shielding for anesthesiologist*** - In **radiotherapy suites**, the anesthesiologist must remain outside the treatment bunker due to high-energy **ionizing radiation**, making **remote monitoring** (cameras and remote displays) essential. - This infrastructure ensures continuous clinical assessment of the pediatric patient while prioritizing the **safety and shielding** of the medical staff from radiation exposure. *Temperature regulation system for hypothermia prevention* - While preventing **hypothermia** is important in pediatric anesthesia, it is a standard requirement for all pediatric cases and not specific to the **radiotherapy environment**. - Unlike surgical suites, radiotherapy rooms are typically maintained at room temperature, making this less critical than the unique challenge of **remote visibility**. *Difficult airway cart with video laryngoscope* - Provision of a **difficult airway cart** is a universal safety standard for any **non-OR anesthesia (NORA)** location, not exclusive to radiation oncology. - While vital for emergency management, it does not address the specific **environmental barrier** created by the radiation treatment field. *MRI-compatible anesthesia machine* - An **MRI-compatible machine** is specifically required for **Magnetic Resonance Imaging** suites to avoid projectile hazards from high magnetic fields. - Radiotherapy involves **linear accelerators**, which do not generate the same magnetic environment as MRI, thus non-magnetic equipment is not a requirement here.
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