General Anesthesia

General Anesthesia Indian Medical PG Question 1: A 40–year female has to undergo incisional hernia surgery under general anaesthesia. She complains of awareness during her past cesarean section. Which of the following monitoring techniques can be used to prevent such awareness ?

• A. Color doppler
• B. Transesophageal echocardiography
• C. Bispectral index monitoring (Correct Answer)
• D. Pulse plethysmography

General Anesthesia Explanation: ***Bispectral index monitoring*** - **Bispectral Index (BIS) monitoring** is a technology that processes electroencephalogram (EEG) signals to provide a numerical value (0-100) indicating the patient's **level of consciousness or depth of anesthesia**. - A lower BIS value (typically 40-60) indicates a suitable depth of anesthesia for surgery, helping to prevent **intraoperative awareness**, especially in patients with a history of it. *Color doppler* - **Color Doppler** is an imaging technique used to visualize blood flow in vessels and assess the speed and direction of flow. - It is primarily used to diagnose conditions like **deep venous thrombosis**, *arterial stenosis*, or to evaluate blood flow to organs, and has no direct role in monitoring depth of anesthesia. *Transesophageal echocardiography* - **Transesophageal echocardiography (TEE)** is an invasive imaging technique that uses ultrasound from a probe inserted into the esophagus to provide detailed images of the heart. - TEE is critical for assessing **cardiac function**, *valvular heart disease*, or *aortic dissection* during surgery, but it does not monitor brain activity or the depth of anesthesia. *Pulse plethysmography* - **Pulse plethysmography** is a non-invasive method that measures changes in blood volume in a part of the body, often used to determine **heart rate** and assess peripheral perfusion. - While it is a component of pulse oximetry, it does not provide information about the **depth of anesthesia** or brain activity.

General Anesthesia Indian Medical PG Question 2: Which of the following intravenous anaesthetic agent causes decrease in postoperative nausea and vomiting :

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

General Anesthesia Explanation: ***Propofol*** - **Propofol** has antiemetic properties, which contributes to a reduced incidence of **postoperative nausea and vomiting (PONV)**. - Its mechanism of action in reducing PONV is thought to involve effects on **dopaminergic receptors** and **serotonin pathways** in the brain. *Etomidate* - **Etomidate** is not known to significantly reduce PONV and may even have a neutral effect or slightly increase it compared to propofol. - Its primary advantages include **cardiovascular stability**, which is unrelated to antiemetic effects. *Ketamine* - **Ketamine** is associated with a higher incidence of PONV, especially at higher doses, due to its **psychedelic side effects** and stimulation of the chemoreceptor trigger zone. - It is known for causing **emergence delirium** and does not possess antiemetic properties. *Thiopentone* - **Thiopentone** (Thiopental) does not have any significant antiemetic properties and is not typically used for its effect on PONV. - It was historically used as an induction agent but has largely been replaced by newer drugs like propofol.

General Anesthesia Indian Medical PG Question 3: Which of the following is most cardio depressant

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

General Anesthesia 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**.

General Anesthesia Indian Medical PG Question 4: Effective adjuvant in attenuating hypertension and tachycardia associated with laryngoscopy and intubation?

• A. Suxamethonium
• B. Fentanyl (Correct Answer)
• C. Ketamine
• D. Atracurium

General Anesthesia Explanation: ***Fentanyl*** - **Fentanyl**, a potent **opioid**, effectively blunts the **sympathetic response** associated with **laryngoscopy** and **intubation**, thereby reducing **hypertension** and **tachycardia**. - Its rapid onset and short duration of action make it a suitable **adjuvant** for this purpose. *Suxamethonium* - **Suxamethonium** is a **depolarizing neuromuscular blocker** used to facilitate intubation, not to attenuate the hemodynamic response. - It does not directly impact **blood pressure** or **heart rate** in a way that would mitigate the stress response. *Ketamine* - **Ketamine** can cause **sympathomimetic effects**, including **increased heart rate** and **blood pressure**, which would worsen rather than attenuate the hemodynamic response to intubation. - It is often used for its **dissociative anesthetic** properties, not for blunting the stress response. *Atracurium* - **Atracurium** is a **nondepolarizing neuromuscular blocker** used for muscle relaxation during intubation and surgery. - It does not directly affect **blood pressure** or **heart rate** in a manner that would attenuate the hypertensive and tachycardic response to laryngoscopy.

General Anesthesia Indian Medical PG Question 5: What causes sudden decreased end tidal CO2 in GA?

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

General Anesthesia 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.

General Anesthesia Flashcard 1 of 5

Question: _____ has the most epileptogenic potential among anesthetic induction agents

Answer: Etomidate

General Anesthesia Flashcard 2 of 5

Question: Neuro/Psych _____ and etomidate are IV anesthetics that exert their effects via potentiation of the GABAA receptor complex

Answer: Propofol

General Anesthesia Flashcard 3 of 5

Question: _____ lowers IOP to levels lower than those achieved with other agents.

Answer: Sevoflurane (general anesthetic)

General Anesthesia Flashcard 4 of 5

Question: _____ has the maximum global warming potential among all the other inhalational anesthetics

Answer: Desflurane

General Anesthesia Flashcard 5 of 5

Question: _____ amphetamine use will decrease the minimum alveolar concentration for an anaesthetic agent

Answer: Chronic (Acute/Chronic)