General Anesthesia Practice Questions

Q: Ketamine can be administered by all of the following routes except?

Subcutaneous (SC). **Explanation:** Ketamine is a unique phencyclidine derivative used for "dissociative anesthesia." The correct answer is **Subcutaneous (SC)** because this route is generally avoided for ketamine administration. Ketamine is highly acidic (pH 3.5 to 5.5) and can be irritating to local tissues, potentially leading to sterile abscesses or skin necrosis if injected subcutaneously. Furthermore, the absorption via this route is unpredictable compared to other systemic options. **Analysis of Options:** * **Intravenous (IV):** This is the most common route for induction. It has a rapid onset (30–60 seconds) and 100% bioavailability. * **Intramuscular (IM):** Ketamine is frequently used IM (especially in pediatrics or uncooperative patients) due to its high lipid solubility. Bioavailability is approximately 90–93%. * **Nasally:** Intranasal ketamine (and its isomer Esketamine) is increasingly used for procedural sedation and treatment-resistant depression. It is absorbed rapidly through the nasal mucosa, bypassing first-pass metabolism. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism of Action:** Non-competitive NMDA receptor antagonist. * **Dissociative State:** Characterized by catatonia, amnesia, and profound analgesia while the patient appears awake (eyes open, slow nystagmic gaze). * **Hemodynamics:** Unlike most anesthetics, it is a **sympathomimetic** (increases HR, BP, and CO), making it the induction agent of choice for **hypovolemic shock**. * **Airway:** It preserves airway reflexes and is a potent **bronchodilator** (drug of choice for status asthmaticus). * **Contraindications:** Raised Intracranial Pressure (ICP) and Intraocular Pressure (IOP), though these are now considered relative contraindications in modern practice. * **Side Effect:** Emergence delirium (minimized by co-administration of benzodiazepines like Midazolam).

Q: Postoperative muscle ache is commonly caused by which of the following agents?

Suxamethonium. **Explanation:** **Suxamethonium (Succinylcholine)** is the correct answer. It is a depolarizing neuromuscular blocker that works by mimicking acetylcholine at the nicotinic receptors of the motor endplate. This causes a sustained depolarization, clinically manifesting as visible muscle twitches known as **fasciculations**. These disorganized contractions lead to micro-trauma of the muscle fibers and the release of lactic acid and potassium, resulting in **postoperative myalgia (muscle ache)**. This pain is most common in the neck, shoulders, and abdominal muscles, typically occurring 24–48 hours post-surgery, and is more frequent in young adults undergoing ambulatory (day-care) surgery. **Why other options are incorrect:** * **d-Tubocurarine, Gallamine, and Pancuronium** are all **Non-depolarizing Neuromuscular Blockers (NDNMBs)**. They act as competitive antagonists at the nicotinic receptors and do not cause initial depolarization or fasciculations. Consequently, they are not associated with postoperative muscle aches. In fact, a small "pre-curarizing" dose of an NDNMB is often used clinically to prevent the fasciculations caused by Suxamethonium. **High-Yield Clinical Pearls for NEET-PG:** * **Prevention:** Post-suxamethonium myalgia can be reduced by pre-treatment with a small dose of a non-depolarizing agent (e.g., Vecuronium) or NSAIDs. * **Contraindications:** Suxamethonium should be avoided in patients with burns, massive trauma, or denervation injuries due to the risk of **hyperkalemia**. * **Genetic Link:** Prolonged apnea after Suxamethonium administration suggests a deficiency or abnormality in **Pseudocholinesterase (Butyrylcholinesterase)**. * **Malignant Hyperthermia:** Suxamethonium is a known trigger for Malignant Hyperthermia in genetically susceptible individuals.

Q: What is the role of egg lecithin in propofol formulation?

Acts as an emulsifying agent. **Explanation:** Propofol is a highly lipid-soluble drug that is insoluble in water. To make it suitable for intravenous administration, it is formulated as an **oil-in-water emulsion**. **1. Why Option A is Correct:** **Egg lecithin** (purified from egg yolk) is a phospholipid that acts as the **emulsifying agent**. It coats the lipid droplets (containing propofol and soybean oil), preventing them from coalescing and ensuring they remain uniformly dispersed in the aqueous phase. This stability is crucial for consistent drug delivery and preventing fat embolism. **2. Why Other Options are Incorrect:** * **Option B (Preservative):** Egg lecithin has no preservative properties. In fact, it supports bacterial growth. EDTA (in Diprivan) or sodium metabisulfite are added as preservatives to inhibit microbial growth. * **Option C (Carrier Vehicle):** **Soybean oil** (10%) acts as the primary lipid vehicle/carrier in which propofol is dissolved. * **Option D (Antibacterial agent):** As mentioned, the lipid emulsion is a potent culture medium for bacteria. It lacks antibacterial properties, which is why strict aseptic techniques must be followed, and the syringe must be discarded within 6–12 hours of opening. **High-Yield Clinical Pearls for NEET-PG:** * **Composition:** 1% Propofol, 10% Soybean oil, 1.2% Egg lecithin, and 2.25% Glycerol (to adjust tonicity). * **Allergy Warning:** While most egg allergies are to egg *white* (albumin), propofol uses egg *yolk* lecithin. However, it is traditionally avoided or used with caution in patients with severe egg anaphylaxis. * **Pain on Injection:** Propofol causes pain due to the activation of the kinin system; this is often mitigated by pre-treatment with Lidocaine. * **PRIS:** Propofol Related Infusion Syndrome is a rare but fatal complication of long-term high-dose infusion, characterized by metabolic acidosis, rhabdomyolysis, and cardiac failure.

Q: Which of the following inhalation agents has a blood-gas partition coefficient similar to nitrous oxide?

Desflurane. ***Correct: Desflurane*** - Desflurane has a **blood-gas partition coefficient** of 0.42, which is the closest value to that of **nitrous oxide (N2O)** (0.47) among the volatile agents listed. - This very low solubility in blood facilitates rapid **wash-in** and **wash-out**, translating to the fastest induction and emergence profiles among potent volatile anesthetics. *Incorrect: Isoflurane* - Isoflurane has a moderate-to-high blood-gas partition coefficient (around **1.4**), indicating high solubility compared to N2O. - Due to its high solubility, it has relatively slow **wash-in** and **wash-out** kinetics, leading to slower induction and emergence. *Incorrect: Sevoflurane* - Sevoflurane has a low blood-gas partition coefficient (around **0.65**), making its onset and offset faster than Isoflurane or Halothane. - Although it is considered a fast agent, its solubility is still higher than both **Desflurane** and **N2O**. *Incorrect: Halothane* - Halothane has the highest blood-gas partition coefficient of the agents listed (approximately **2.5**). - Its high solubility results in the slowest **induction** and **emergence** profiles because the blood must be saturated significantly before the partial pressure in the brain rises enough to cause anesthesia.

Q: A 35 y/o asthmatic patient is scheduled for a minor surgical procedure. Which induction agent and muscle relaxant combination is safest for this patient?

Ketamine and Vecuronium. ***Ketamine and Vecuronium***- **Ketamine** is strongly recommended for asthmatics as it possesses potent **bronchodilating properties** via its sympathomimetic effects, helping prevent **bronchospasm**.- **Vecuronium** is an intermediate-acting non-depolarizing muscle relaxant that causes **minimal to no histamine release**, ensuring cardiovascular stability and avoiding airway irritation.*Propofol and Succinylcholine*- While **Propofol** is often used and generally considered safe (neutral to mild bronchodilation), **Succinylcholine**, a depolarizing agent, carries a potential risk of **histamine release**, although low.- The combination is generally acceptable but less preferred than Ketamine based on the strength of Ketamine's **bronchodilating effect**.*Ketamine and d-tubocurarine*- **Ketamine** is beneficial due to its **bronchodilating effect**, but **d-tubocurarine (DTC)** is highly associated with massive **histamine release**.- DTC often causes severe **hypotension** and significant **bronchospasm**, making it extremely unsafe for an asthmatic patient.*Thiopental and Rocuronium*- **Thiopental**, a barbiturate, is associated with a risk of **histamine release** and potential exacerbation of asthma symptoms or cough upon induction.- Although **Rocuronium** is a safe, low-histamine muscle relaxant, the use of **Thiopental** makes this combination less safe than using Ketamine.

Q: A patient undergoing surgery receives a muscle relaxant and soon develops flushing and rashes over the neck and anterior chest. Which of the following muscle relaxants is most commonly associated with this reaction?

Atracurium. ***Atracurium*** - The characteristic reaction described (flushing and rashes over the neck and chest) is often termed an **anaphylactoid reaction** due to **direct non-immunological histamine release** from mast cells. - Among the non-depolarizing muscle relaxants, **atracurium** and mivacurium are the most common causes of significant, dose-dependent histamine release, leading to cutaneous vasodilation (flushing) and potential hypotension. *Cisatracurium* - Although cisatracurium is an isomer of atracurium, it is associated with a **significantly lower incidence** of **histamine release** and provides better cardiovascular stability. - It is often favored over atracurium for patients with severe cardiovascular disease. *Vecuronium* - Vecuroniumbelongs to the **aminosteroid class** (e.g., rocuronium, vecuronium, pancuronium) of muscle relaxants, which are generally associated with **minimal-to-negligible risk** of **histamine release**. - It is preferred for its high degree of **cardiovascular stability** (minimal effect on heart rate or blood pressure). *Pancuronium* - Pancuronium, another **aminosteroid**, has a very low potential for histamine release, thus not typically causing flushing or rash. - Its main side effect is a **vagolytic action** (antimuscarinic effect) that often causes significant **tachycardia** and hypertension.

Q: A 50-year-old male patient underwent lower abdominal surgery under general anaesthesia. Vecuronium was administered as a muscle relaxant during the procedure. At the end of the surgery, which of the following is the most appropriate agent to reverse the effects of vecuronium?

Neostigmine. ### **Explanation** The correct answer is **B. Neostigmine**. #### **Mechanism of Action** **Vecuronium** is a **non-depolarizing neuromuscular blocking agent (NDMR)** that works by competitively inhibiting nicotinic acetylcholine receptors at the neuromuscular junction. To reverse its effects, we must increase the concentration of acetylcholine (ACh) at the synapse. **Neostigmine** is an **acetylcholinesterase inhibitor**. By inhibiting the enzyme that breaks down ACh, it increases the availability of ACh, which then outcompetes the vecuronium molecules for the receptor sites, thereby restoring muscle power. #### **Analysis of Incorrect Options** * **A. Baclofen:** This is a **GABA-B agonist** used as a centrally acting muscle relaxant for chronic spasticity (e.g., multiple sclerosis). it has no role in reversing surgical neuromuscular blockade. * **C. Atropine:** This is an **anticholinergic (muscarinic antagonist)**. While it is almost always given *alongside* neostigmine to prevent bradycardia and secretions caused by increased ACh at muscarinic sites, it does not reverse the muscle relaxant effect itself. * **D. Drotaverine:** This is an **antispasmodic** (phosphodiesterase-4 inhibitor) used primarily for smooth muscle relaxation in cases of biliary or renal colic. #### **High-Yield Clinical Pearls for INI-CET** * **The "Gold Standard" Pair:** Neostigmine is co-administered with **Glycopyrrolate** (preferred over Atropine) to counteract the parasympathetic side effects (bradycardia, salivation, bronchospasm). * **Sugammadex:** A newer, high-yield reversal agent specifically for **Rocuronium** and **Vecuronium**. It works by **encapsulation** (chelating the drug) rather than enzyme inhibition. * **Monitoring:** Reversal should ideally be guided by **Train-of-Four (TOF)** monitoring; a TOF ratio of **>0.9** indicates adequate recovery from blockade.

Q: Which is correct about the anesthetic drugs X and Y respectively?

Drug Y has more potency than drug X. ***Drug Y has more potency than drug X*** - The graph shows that as the **oil:gas partition coefficient** increases, the **Minimum Alveolar Concentration (MAC)** decreases. A lower MAC indicates **higher potency** for an inhaled anesthetic. - Drug Y has a higher oil:gas partition coefficient than drug X (meaning it's more lipid-soluble and thus more potent) and a lower MAC value, making it **more potent** than Drug X. *Drug X has more potency than drug Y* - Drug X has a higher MAC value and a lower oil:gas partition coefficient compared to Drug Y. - A higher MAC value signifies **lower potency**, as a greater concentration is needed to achieve the same anesthetic effect. *Drug X and Y have equal potency* - The graph clearly demonstrates that Drug X and Drug Y have different MAC values and different oil:gas partition coefficients. - Since MAC is inversely related to potency, different MAC values directly imply **different potencies**. *Drug X and Y have equal potency but different speed of recovery* - As established, Drug X and Drug Y do not have equal potency due to their different MAC values. - While lipid solubility (represented by the oil:gas partition coefficient) does affect the **speed of recovery** (higher coefficients generally lead to slower recovery), the premise of equal potency is incorrect.

Q: Which is correct about the anesthetic drugs X and Y in the image shown? (Recent NEET Pattern 2016-17)

Drug X is more fast acting than Y. ***Drug X is more fast acting than Y*** - The **oil:gas partition coefficient** for Drug X is lower than for Drug Y. A lower oil:gas partition coefficient typically correlates with a **faster onset of action** for inhaled anesthetics as it indicates lower solubility in blood and tissues, allowing for quicker equilibration in the brain. - While MAC is plotted against oil:gas partition coefficient, the question specifically asks about **onset of action**, which is primarily influenced by blood-gas solubility rather than oil-gas solubility. However, an anesthetic with lower oil-gas solubility (like X) would generally also have lower blood-gas solubility, leading to faster onset. *Drug Y is more fast acting than X* - Drug Y has a **higher oil:gas partition coefficient** compared to Drug X, indicating greater lipid solubility. - A higher oil:gas partition coefficient generally correlates with a **slower onset of action** for inhaled anesthetics, as more drug dissolves in lipids before reaching the brain. *Drug X and Y have equally fast onset of action* - The graph clearly shows that Drug X and Drug Y have different **oil:gas partition coefficients**. - Since the partition coefficients are different, their **solubility characteristics** and therefore their clinical onset of action would also be different. *Drug X and Y have equally fast onset of action but potency of X is more than Y* - Onset of action is **not equal** for X and Y due to their differing oil:gas partition coefficients. - Potency, represented by **MAC** (Minimum Alveolar Concentration), is inversely related to the oil:gas partition coefficient for many inhaled anesthetics. From the graph, Drug X has a higher MAC value than Drug Y (meaning it is **less potent** but acts faster).

Q: The commonly used muscle relaxant with quickest onset of action and spontaneous recovery is :

Suxamethonium. ***Suxamethonium*** - Suxamethonium (succinylcholine) is a **depolarizing neuromuscular blocker** with the most rapid onset of action (30-60 seconds) due to its unique mechanism. - Its short duration of action and **spontaneous recovery** are due to its rapid hydrolysis by **plasma pseudocholinesterase**, making it ideal for rapid sequence intubation. *Vecuronium* - Vecuronium is an **intermediate-duration non-depolarizing neuromuscular blocker** with an onset of action typically around 3-5 minutes, which is slower than suxamethonium. - It does not undergo spontaneous recovery as rapidly as suxamethonium and often requires administration of a **reversal agent**. *Rocuronium* - Rocuronium is a **non-depolarizing neuromuscular blocker** known for its relatively rapid onset of action (60-90 seconds) among non-depolarizing agents, but it is still slower than suxamethonium. - While it can be reversed quickly with sugammadex, its **spontaneous recovery** is much slower than suxamethonium. *Atracurium* - Atracurium is an **intermediate-duration non-depolarizing neuromuscular blocker** with an onset of action (3-5 minutes) that is slower than suxamethonium. - Its metabolism involves **Hofmann elimination** and ester hydrolysis, providing a degree of organ-independent elimination, but its recovery is not as rapid or spontaneous as suxamethonium.

Question 1

Ketamine can be administered by all of the following routes except?

Accepted Answer

Subcutaneous (SC)

Answer

Intravenous (IV)

Answer

Intramuscular (IM)

Answer

Nasally

Question 2

Postoperative muscle ache is commonly caused by which of the following agents?

Accepted Answer

Suxamethonium

Answer

d-Tubocurarine

Answer

Gallamine

Answer

Pancuronium

Question 3

What is the role of egg lecithin in propofol formulation?

Accepted Answer

Acts as an emulsifying agent

Answer

Acts as a preservative

Answer

Acts as a carrier vehicle

Answer

Acts as an antibacterial agent

Question 4

Which of the following inhalation agents has a blood-gas partition coefficient similar to nitrous oxide?

Accepted Answer

Desflurane

Answer

Isoflurane

Answer

Halothane

Answer

Sevoflurane

Question 5

A 35 y/o asthmatic patient is scheduled for a minor surgical procedure. Which induction agent and muscle relaxant combination is safest for this patient?

Accepted Answer

Ketamine and Vecuronium

Answer

Propofol and Succinylcholine

Answer

Ketamine and d-tubocurarine

Answer

Thiopental and Rocuronium

Question 6

A patient undergoing surgery receives a muscle relaxant and soon develops flushing and rashes over the neck and anterior chest. Which of the following muscle relaxants is most commonly associated with this reaction?

Accepted Answer

Atracurium

Answer

Vecuronium

Answer

Pancuronium

Answer

Cisatracurium

Question 7

A 50-year-old male patient underwent lower abdominal surgery under general anaesthesia. Vecuronium was administered as a muscle relaxant during the procedure. At the end of the surgery, which of the following is the most appropriate agent to reverse the effects of vecuronium?

Accepted Answer

Neostigmine

Answer

Baclofen

Answer

Atropine

Answer

Drotaverine

Question 8

Which is correct about the anesthetic drugs X and Y respectively?

Accepted Answer

Drug Y has more potency than drug X

Answer

Drug X has more potency than drug Y

Answer

Drug X and Y have equal potency

Answer

Drug X and Y have equal potency but different speed of recovery

Question 9

Which is correct about the anesthetic drugs X and Y in the image shown? (Recent NEET Pattern 2016-17)

Accepted Answer

Drug X is more fast acting than Y

Answer

Drug X and Y have equally fast onset of action

Answer

Drug X and Y have equally fast onset of action but potency of X is more than Y

Answer

Drug Y is more fast acting than X

Question 10

The commonly used muscle relaxant with quickest onset of action and spontaneous recovery is :

Accepted Answer

Suxamethonium

Answer

Vecuronium

Answer

Rocuronium

Answer

Atracurium

General Anesthesia — MCQs

General Anesthesia — MCQs

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