General Anesthesia Practice Questions

Q: Use of nitrous oxide is contraindicated in all of the following surgeries except?

Exentration operation. **Explanation:** The core concept behind this question is the **Blood-Gas Partition Coefficient** of Nitrous Oxide ($N_2O$). $N_2O$ is 34 times more soluble in blood than Nitrogen ($N_2$). Consequently, $N_2O$ leaves the blood and enters air-filled closed spaces faster than $N_2$ can leave them, leading to an increase in **volume** (in compliant spaces) or **pressure** (in non-compliant spaces). **Why Exenteration is the Correct Answer:** Exenteration (orbital or pelvic) involves the radical removal of contents from an open body cavity. Since there is no enclosed, air-filled space, $N_2O$ cannot cause pressure buildup or expansion. Therefore, it is safe to use. **Why the Other Options are Contraindicated:** * **Cochlear Implant/Tympanoplasty:** The middle ear is a non-compliant space. $N_2O$ increases middle ear pressure, which can displace a tympanic membrane graft or interfere with delicate implant placement. * **Microlaryngeal Surgery:** These procedures often involve the use of lasers. $N_2O$ supports combustion and increases the risk of an **airway fire**, making it hazardous. * **Vitreoretinal Surgery:** If an intraocular gas bubble (e.g., $SF_6$ or $C_3F_8$) is used to flatten the retina, $N_2O$ will rapidly diffuse into the bubble, increasing intraocular pressure (IOP) and potentially causing retinal artery occlusion and blindness. **High-Yield Clinical Pearls for NEET-PG:** * **Diffusion Hypoxia:** Occurs at the end of surgery when $N_2O$ floods the alveoli; prevent by giving 100% $O_2$ for 5–10 minutes. * **Second Gas Effect:** $N_2O$ speeds up the uptake of a companion volatile anesthetic. * **Absolute Contraindications:** Pneumothorax (doubles in size in 10 mins), air embolism, bowel obstruction, and recent vitreoretinal surgery (avoid $N_2O$ for 7–10 days after $SF_6$ use).

Q: All the following are true about Regional anesthesia EXCEPT?

Increases blood loss. **Explanation:** The correct answer is **A (Increases blood loss)** because Regional Anesthesia (RA), specifically neuraxial blocks like spinal and epidural anesthesia, actually **decreases** intraoperative blood loss. This occurs due to two primary mechanisms: 1. **Sympathetic Blockade:** Leads to vasodilation and a controlled reduction in mean arterial pressure (hypotension). 2. **Reduced Venous Pressure:** Lowering peripheral venous pressure reduces oozing from the surgical site. **Analysis of other options:** * **Option B & D:** RA is associated with fewer complications in major surgeries. In **vascular surgery**, it reduces the risk of graft thrombosis (due to improved blood flow and attenuated hypercoagulability). In **colon surgery**, it facilitates earlier return of bowel function (reduced ileus) and provides superior analgesia compared to opioids, which can slow motility. * **Option C:** While RA can cause shivering due to core-to-peripheral heat redistribution, it is often used to **decrease the metabolic stress response** and oxygen consumption associated with the intense shivering seen during emergence from General Anesthesia (GA). **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard for Post-op Pain:** Epidural analgesia is superior to systemic opioids for major abdominal and thoracic surgeries. * **DVT/PE Prophylaxis:** RA significantly reduces the incidence of Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE) by improving lower limb blood flow and preventing the pro-thrombotic state triggered by surgical stress. * **Cardiac Benefits:** RA reduces the incidence of postoperative myocardial infarction by decreasing the surge in catecholamines.

Q: Which of the following anesthetic drugs is contraindicated in hepatic failure?

Halothane. **Explanation:** **Halothane** is the correct answer because of its significant potential for hepatotoxicity, historically categorized into two types: a mild, transient elevation of transaminases and a rare, life-threatening condition known as **Halothane Hepatitis**. The underlying mechanism involves the metabolism of halothane by the cytochrome P450 system into **trifluoroacetylated (TFA) proteins**. In susceptible individuals, these act as haptens, triggering an immune-mediated response that leads to massive hepatic necrosis. Because halothane undergoes significant hepatic metabolism (up to 20%), it is strictly contraindicated in patients with pre-existing hepatic failure or a history of unexplained jaundice after previous exposure. **Analysis of Incorrect Options:** * **Desflurane & Isoflurane:** These are modern volatile anesthetics with much lower metabolism rates (0.02% and 0.2%, respectively). They produce minimal TFA proteins and are considered safe alternatives in patients with liver disease. * **Remifentanil:** This is an ultra-short-acting opioid metabolized by **non-specific plasma and tissue esterases**, not the liver. Its clearance is entirely independent of hepatic function, making it an ideal choice for patients with liver failure. **High-Yield Clinical Pearls for NEET-PG:** * **Metabolism Rule:** Halothane (20%) > Sevoflurane (2%) > Isoflurane (0.2%) > Desflurane (0.02%). * **Drug of Choice:** **Isoflurane** is often preferred in liver surgery because it best preserves hepatic blood flow (the "Hepatic Artery Buffer Response"). * **Atracurium/Cisatracurium:** These are the muscle relaxants of choice in hepatic failure due to **Hofmann elimination**.

Q: What is the definitive sign of stage I of anesthesia?

Fixation of the eyeball. **Explanation:** The stages of anesthesia are traditionally described using **Guedel’s Classification**, which was originally based on the effects of diethyl ether. **Why "Fixation of the eyeball" is correct:** Stage I (Stage of Analgesia) begins from the induction of anesthesia and lasts until the loss of consciousness. As the patient transitions from Stage I to Stage II (Stage of Excitement), the eyes, which were previously moving or wandering, become **fixed** in a central position. Therefore, the fixation of the eyeball is considered the definitive clinical sign marking the end of Stage I and the onset of the deeper planes of anesthesia. **Analysis of Incorrect Options:** * **B. Pupillary dilatation:** This is characteristic of **Stage II** (due to sympathetic stimulation) or **Stage IV** (due to medullary depression/toxic overdose). It is not a definitive sign of Stage I. * **C. Blurring of vision:** While this occurs during Stage I as the patient loses sensory perception, it is a subjective symptom rather than a definitive clinical sign used by the anesthetist to stage anesthesia. * **D. Intercostal paralysis:** This is a hallmark of **Stage III, Plane 3** (Surgical Anesthesia). It indicates deep anesthesia where breathing becomes purely diaphragmatic. **High-Yield Clinical Pearls for NEET-PG:** * **Stage I:** Analgesia and amnesia occur. The patient is conscious but drowsy. * **Stage II (Excitement):** Risk of laryngospasm, vomiting, and irregular respiration. The goal is to pass through this stage as quickly as possible. * **Stage III (Surgical Anesthesia):** Divided into 4 planes. **Plane 2** is the ideal plane for most surgeries (loss of corneal and laryngeal reflexes). * **Stage IV (Medullary Paralysis):** Respiratory and vasomotor center failure; this is an overdose stage and must be avoided.

Q: Which of the following statements regarding halothane is true?

Reduces arterial pressure. **Explanation:** Halothane is a potent volatile anesthetic agent that primarily causes a dose-dependent reduction in arterial blood pressure. **1. Why Option A is Correct:** Halothane reduces arterial pressure through two main mechanisms: **direct myocardial depression** (negative inotropy) and a reduction in cardiac output. Unlike other volatile agents (like isoflurane), it causes minimal peripheral vasodilation, meaning the drop in blood pressure is almost entirely due to its effect on the heart muscle itself. **2. Why the other options are incorrect:** * **Option B (Increases heart rate):** Halothane actually tends to cause **bradycardia** or maintain a normal heart rate. It blunts the baroreceptor reflex, meaning the body does not mount a compensatory tachycardia in response to the falling blood pressure. * **Option C (Decreases cardiac output):** While halothane *does* decrease cardiac output, the question asks for the most definitive clinical effect. In many standardized exams, "reduction in arterial pressure" is considered the hallmark hemodynamic effect of halothane. (Note: In some contexts, C is also physiologically true, but A is the primary clinical manifestation). * **Option D (Increases sympathoadrenal activity):** Halothane **depresses** the sympathetic nervous system. It does not cause the "sympathetic surge" seen with agents like desflurane. **High-Yield NEET-PG Pearls for Halothane:** * **Catecholamine Sensitization:** Halothane sensitizes the myocardium to epinephrine, increasing the risk of **ventricular arrhythmias** if exogenous adrenaline is used. * **Hepatotoxicity:** Associated with "Halothane Hepatitis" (Type II is immune-mediated and severe). * **Uterine Relaxation:** It is a potent uterine relaxant, making it useful for version but risky for postpartum hemorrhage. * **Sweet Odor:** It is non-pungent, making it the classic agent for **smooth inhalation induction** in pediatric patients.

Q: All of the following are features of Verrill's sign except?

Tingling sensation. **Verrill’s sign** is a clinical endpoint used primarily in intravenous sedation (conscious sedation), most commonly associated with the administration of benzodiazepines like **Diazepam** or **Midazolam**. It serves as a reliable indicator that the patient has reached an adequate level of sedation for dental or minor surgical procedures without progressing into deep anesthesia or respiratory depression. ### **Explanation of Options:** * **Correct Answer: B (Tingling sensation):** Tingling (paresthesia) is not a component of Verrill’s sign. While some patients may experience subjective sensations during drug induction, it is not a clinical marker of the sedation endpoint. * **Option A (Partial ptosis):** This is the **hallmark** of Verrill’s sign. It is defined as the drooping of the upper eyelid such that it covers approximately **half of the pupil**. * **Option C & D (Blurring vision & Slurring speech):** These are associated signs of central nervous system depression. As the patient approaches the Verrill’s sign endpoint, they typically experience diplopia (double vision), blurred vision, and a noticeable slowing or slurring of speech. ### **Clinical Pearls for NEET-PG:** 1. **The "50% Rule":** Verrill’s sign is specifically the **50% ptosis** of the eyelid. If ptosis exceeds this or the patient loses the lash reflex, they are entering a deeper stage of anesthesia than intended for conscious sedation. 2. **Guedel’s Chart vs. Verrill’s:** While Guedel’s stages describe ether anesthesia, Verrill’s sign is the specific gold standard for **IV Diazepam sedation**. 3. **Safety Margin:** Reaching Verrill’s sign indicates that the patient is relaxed and amnesic but can still maintain a patent airway and respond to verbal commands. 4. **O'Beirne's Sign:** Do not confuse Verrill's with O'Beirne's sign (related to the rectum/defecation) or Guedel's signs (stages of GA).

Q: What is the inducing agent of choice in DIC?

Ketamine. **Explanation:** The correct answer is **Ketamine**. In patients with **Disseminated Intravascular Coagulation (DIC)**, the primary clinical concern during induction is hemodynamic instability and severe hypotension, often resulting from underlying sepsis, trauma, or obstetric emergencies. **Why Ketamine is the choice:** Ketamine is a phencyclidine derivative that acts as a potent sympathomimetic. It stimulates the release of endogenous catecholamines, leading to an increase in heart rate, blood pressure, and cardiac output. This "pressor effect" makes it the induction agent of choice in hemodynamically unstable patients (shock) or those with active bleeding, which are common precursors to DIC. **Analysis of Incorrect Options:** * **Thiopentone:** A barbiturate that causes significant peripheral vasodilation and direct myocardial depression. In a patient with DIC/shock, this can lead to a catastrophic drop in blood pressure. * **Propofol:** Similar to Thiopentone, Propofol causes marked vasodilation and decreases systemic vascular resistance (SVR). It is contraindicated in patients who are hemodynamically compromised. * **Methohexitone:** Another barbiturate that, like Thiopentone, causes cardiovascular depression and is generally avoided in unstable patients. **High-Yield Clinical Pearls for NEET-PG:** * **Agent of choice for Shock/Hypovolemia:** Ketamine. * **Agent of choice for Bronchial Asthma:** Ketamine (due to bronchodilatory properties). * **Agent of choice for Day-care Surgery:** Propofol (due to rapid recovery and anti-emetic properties). * **Agent of choice for Neurosurgery/Increased ICT:** Thiopentone (decreases Cerebral Metabolic Rate and ICP). * **Contraindication for Ketamine:** Patients with Hypertension, IHD, or increased Intraocular/Intracranial pressure.

Q: What is the definition of conscious sedation?

Sedation with ability to respond to verbal commands. **Explanation:** **Conscious Sedation** (also known as Procedural Sedation) is a drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. 1. **Why Option C is correct:** The hallmark of conscious sedation is the maintenance of the patient’s **airway reflexes** and the **ability to follow commands**. While the patient’s coordination and cognitive function may be impaired, they remain conscious and do not require mechanical ventilation or airway adjuncts. 2. **Why other options are incorrect:** * **Option A:** CNS depression with unconsciousness describes **General Anesthesia**, where the patient is unarousable even by painful stimuli and often requires airway support. * **Option B:** Inability to respond to verbal commands indicates **Deep Sedation**. In this state, patients can only be aroused by repeated or painful stimulation, and their spontaneous ventilation may be inadequate. **High-Yield Clinical Pearls for NEET-PG:** * **Continuum of Sedation:** Sedation is a spectrum: Minimal (Anxiolysis) → Moderate (Conscious) → Deep → General Anesthesia. * **Airway:** In conscious sedation, spontaneous ventilation is adequate, and cardiovascular function is usually maintained. * **Common Drugs:** Midazolam (Benzodiazepine) and Fentanyl (Opioid) are frequently used. Propofol can be used but carries a higher risk of transitioning the patient into deep sedation or general anesthesia. * **Monitoring:** Pulse oximetry and clinical monitoring of respiratory rate and heart rate are mandatory.

Question 1

Use of nitrous oxide is contraindicated in all of the following surgeries except?

Accepted Answer

Exentration operation

Answer

Cochlear implant

Answer

Microlaryngeal surgery

Answer

Vitrioretinal surgery

Question 2

All the following are true about Regional anesthesia EXCEPT?

Accepted Answer

Increases blood loss

Answer

Less complications after vascular surgery

Answer

Decreases shivering after induction of anaesthesia

Answer

Less complications after colon surgery

Question 3

Which of the following anesthetic drugs is contraindicated in hepatic failure?

Accepted Answer

Halothane

Answer

Desflurane

Answer

Remifentanil

Answer

Isoflurane

Question 4

What is the definitive sign of stage I of anesthesia?

Accepted Answer

Fixation of the eyeball

Answer

Pupillary dilatation

Answer

Blurring of vision

Answer

Intercostal paralysis

Question 5

Pentothal sodium should preferably be injected into which of the following veins?

Accepted Answer

Veins on the outer aspect of the forearm

Answer

Femoral vein

Answer

Antecubital vein

Answer

Neck vein

Question 6

Which of the following statements regarding halothane is true?

Accepted Answer

Reduces arterial pressure

Answer

Increases heart rate

Answer

Decreases cardiac output

Answer

Increases sympathoadrenal activity

Question 7

The plane of surgical anesthesia during ether anesthesia is defined as?

Accepted Answer

From onset of regular respiration to cessation of spontaneous breathing

Answer

Loss of consciousness

Answer

Loss of consciousness to the onset of spontaneous respiration

Answer

Absence of reflexes

Question 8

All of the following are features of Verrill's sign except?

Accepted Answer

Tingling sensation

Answer

Partial ptosis

Answer

Blurring vision

Answer

Slurring speech

Question 9

What is the inducing agent of choice in DIC?

Accepted Answer

Ketamine

Answer

Thiopentone

Answer

Methohexitone

Answer

Propofol

Question 10

What is the definition of conscious sedation?

Accepted Answer

Sedation with ability to respond to verbal commands

Answer

Central nervous system depression with unconsciousness

Answer

Sedation with inability to respond to verbal commands

Answer

Any of the above

General Anesthesia — MCQs

General Anesthesia — MCQs

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