Awareness Under General Anesthesia — MCQs

10 questions

Premedication is prescribed to – a) Allay anxiety b) Make the patient asleep before coming for operation c) Reduce the dose of induction agents d) Produce amnesia

Most sensitive method of monitoring cardiovascular ischemia in the perioperative period is -

Which of the following excludes painful stimuli from awareness?

A 1st year medical student presents with recurrent episodes of choking sensation, breathlessness, intense sweating along with feeling of impending doom. Usually the episodes occur prior to exams. What is the most likely diagnosis?

Awareness during anaesthesia can be assessed by:

Depth of anaesthesia can be best assessed by

What causes sudden decreased end tidal CO2 in GA?

Problems which may result from hypotensive anesthesia include:

A cardiovascular parameter helpful in diagnosis of anaphylaxis during anaesthesia:

Q10

On repeated use, which of the following inhalational anaesthetic agent can cause hepatitis:

Awareness Under General Anesthesia Indian Medical PG Practice Questions and MCQs

Question 1: Premedication is prescribed to – a) Allay anxiety b) Make the patient asleep before coming for operation c) Reduce the dose of induction agents d) Produce amnesia

A. Reduce the dose of induction agents
B. Allay anxiety (Correct Answer)
C. Produce amnesia
D. Make the patient asleep before coming for operation

Explanation: ***Allay anxiety*** - Premedication frequently includes anxiolytic agents like **benzodiazepines** to calm the patient before surgery. - Reducing anxiety helps in achieving a smoother induction of anesthesia and can improve the patient's overall experience. *Reduce the dose of induction agents* - While some premedication agents like **opioids** or sedatives can have an anesthetic-sparing effect, this is a secondary benefit, not the primary goal. - The main aim is patient comfort and psychological preparation, not primarily dose reduction. *Produce amnesia* - Amnesia, particularly **anterograde amnesia**, is a desirable side effect of some premedication drugs like **midazolam**. - However, it's a consequence of the anxiolytic effect rather than the sole or primary reason for prescribing premedication. *Make the patient asleep before coming for operation* - While some premedication agents can cause **somnolence** or light sleep, the goal is not to have the patient fully asleep before entering the operating room. - The primary aim is to make the patient relaxed and comfortable, not unconscious.

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: Which of the following excludes painful stimuli from awareness?

A. Repression (Correct Answer)
B. Reaction formation
C. Projection
D. Rationalization

Explanation: ***Repression*** - **Repression** is a defense mechanism where the mind unconsciously blocks disturbing thoughts, memories, or impulses from entering awareness. - It serves to remove painful stimuli or unacceptable desires from conscious perception, preventing emotional distress. - This is the primary mechanism that **excludes painful stimuli from awareness**. *Reaction formation* - **Reaction formation** is a defense mechanism where a person unconsciously replaces an unacceptable impulse with its opposite. - For example, showing excessive kindness to someone one dislikes. - This does not directly exclude painful stimuli from awareness but transforms the expression of the impulse. *Projection* - **Projection** involves attributing one's own unacceptable thoughts, feelings, or impulses to another person. - This mechanism shifts blame or undesirable traits onto others rather than blocking the original painful stimulus from awareness. - The person remains aware of the trait but misattributes its source. *Rationalization* - **Rationalization** is the cognitive distortion of facts to make an unacceptable action or impulse appear more acceptable or logically justifiable. - It involves constructing a plausible but false reason for one's actions. - While it reduces anxiety, it doesn't exclude the original painful stimulus from awareness—rather, it reinterprets it.

Question 4: A 1st year medical student presents with recurrent episodes of choking sensation, breathlessness, intense sweating along with feeling of impending doom. Usually the episodes occur prior to exams. What is the most likely diagnosis?

A. Panic attack (Correct Answer)
B. Acute stress disorder
C. Generalised anxiety disorder
D. Phobia

Explanation: ***Panic attack (Panic Disorder)*** - The sudden onset of intense fear or discomfort, along with symptoms like **choking sensation**, **breathlessness**, **sweating**, and **feeling of impending doom**, are characteristic of a **panic attack**. - The **recurrent episodes** occurring prior to exams indicate **Panic Disorder**, which is defined by recurrent unexpected panic attacks followed by persistent concern about future attacks. - The situational trigger (exams) suggests a pattern consistent with panic disorder, where attacks may be situationally predisposed. *Acute stress disorder* - This condition occurs within **one month of exposure to a traumatic event** and involves dissociative symptoms, intrusions, avoidance, and arousal symptoms. - The patient describes recurrent episodes tied to exams, not a single acute traumatic event with subsequent stress response. *Generalised anxiety disorder* - Characterized by excessive and **uncontrollable worry** about various events or activities for **at least six months**. - While anxiety is present, the sudden, intense, **episodic nature** of symptoms with a distinct "feeling of impending doom" points away from the chronic, pervasive worry of GAD. - GAD presents with chronic anxiety rather than discrete panic episodes. *Phobia* - A phobia is an **irrational and intense fear** of a specific object or situation (e.g., specific phobia) or social situations (social anxiety disorder). - While exam-related anxiety can be severe, the description points to a **full-blown panic response** with multiple autonomic symptoms (choking, breathlessness, sweating) and psychological distress (impending doom). - Unlike a phobia where avoidance is the primary feature, this patient experiences discrete panic episodes with characteristic somatic symptoms.

Question 5: Awareness during anaesthesia can be assessed by:

A. ARTERIAL B.P
B. ETCO2
C. BIS (Correct Answer)
D. NEUROMUSCULAR MONITOR

Explanation: ***

Question 6: Depth of anaesthesia can be best assessed by

A. ABG analysis
B. Pulse oximeter
C. End tidal Pco2
D. Bispectral index (Correct Answer)

Explanation: ***Bispectral index*** - The **Bispectral Index (BIS)** monitor processes **electroencephalogram (EEG)** signals to provide a numerical value (0-100) indicating the **level of consciousness** and hypnotic depth during anesthesia. - A lower BIS value (typically 40-60) indicates a deeper anesthetic state, helping clinicians avoid **awareness during surgery** and guide anesthetic agent delivery. *ABG analysis* - **Arterial Blood Gas (ABG)** analysis measures parameters like pH, PCO2, PO2, and bicarbonate, reflecting the patient's **acid-base balance** and **oxygenation**. - While important for overall physiological status, ABG analysis does not directly assess the **depth of anesthesia** or the patient's level of consciousness. *Pulse oximeter* - A **pulse oximeter** measures **oxygen saturation (SpO2)** and heart rate, reflecting the adequacy of oxygen delivery. - It does not provide information about the **depth of consciousness** or the hypnotic effect of anesthetic agents. *End tidal Pco2* - **End-tidal PCO2 (EtCO2)** monitors the partial pressure of carbon dioxide at the end of exhalation, providing an indication of **ventilation** and CO2 elimination. - While EtCO2 is crucial for managing ventilation during anesthesia, it does not directly reflect the **depth of anesthesia** or the patient's neurological state.

Question 7: What causes sudden decreased end tidal CO2 in GA?

A. Cardiac arrest (Correct Answer)
B. Pulmonary embolism
C. Pulmonary hypertension
D. Malignant hyperthermia

Explanation: ***Cardiac arrest*** - In **cardiac arrest**, there is a sudden cessation of effective **cardiac output**, which leads to a dramatic reduction in pulmonary blood flow. - As a result, **CO2 is not transported to the lungs** for exhalation, causing an abrupt and severe drop in **end-tidal CO2**. *Pulmonary embolism* - A **pulmonary embolism** causes an acute obstruction of pulmonary arterial blood flow, leading to an **increase in alveolar dead space**. - While it can decrease **end-tidal CO2** due to reduced perfusion, the drop is often less sudden and complete than in cardiac arrest, and the primary mechanism is **ventilation-perfusion mismatch**. *Pulmonary hypertension* - **Pulmonary hypertension** involves chronically elevated pressures in the pulmonary arteries, which can lead to **right ventricular dysfunction** and reduced cardiac output over time. - It typically causes a more gradual and chronic reduction in **end-tidal CO2** due to impaired gas exchange, rather than a sudden, precipitous drop. *Malignant hyperthermia* - **Malignant hyperthermia** is characterized by a rapid and severe increase in **metabolic rate** and CO2 production. - This condition typically leads to a **sudden increase in end-tidal CO2** as the body produces more CO2 than can be eliminated, rather than a decrease.

Question 8: 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 9: 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 10: On repeated use, which of the following inhalational anaesthetic agent can cause hepatitis:

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

Explanation: ***Halothane*** - **Halothane** is metabolized to **trifluoroacetylated proteins** in the liver, which can act as neoantigens, triggering an immune response and **hepatitis**, particularly with repeated exposure. - This condition, known as **halothane-induced hepatitis** or **halothane-associated liver damage**, is a potentially fatal idiosyncratic reaction. *Isoflurane* - **Isoflurane** is metabolized to a very small extent (0.2%), significantly reducing the risk of metabolite-induced organ toxicity, including hepatitis. - It is considered a safer alternative to halothane in patients susceptible to liver dysfunction. *Sevoflurane* - **Sevoflurane** undergoes minimal hepatic metabolism (about 5%) and is primarily eliminated unchanged by the lungs. - While it can produce **Compound A** via reaction with CO2 absorbents, this is primarily associated with renal, not hepatic, toxicity. *Ether* - **Diethyl ether** is rarely used in modern anesthesia due to its flammability, slow induction, and recovery times. - Although it is metabolized in the liver, it rarely causes significant **hepatotoxicity** or hepatitis.

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