General Anesthesia — MCQs

General Anesthesia Indian Medical PG Practice Questions and MCQs

Question 531: Which of the following anesthetic agent is not painful on intravenous administration?

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

Explanation: ***Ketamine*** - **Ketamine** is known for causing minimal pain on intravenous administration compared to other common induction agents. - Its mechanism of action as an **NMDA receptor antagonist** does not involve irritation of venous endothelium to the same extent as some other anesthetics. *Propofol* - **Propofol** is infamous for causing significant **injection pain** due to its formulation, which contains soybean oil, glycerol, and egg lecithin, acting as a direct irritant to the intima of veins. - The pain is often described as a **burning sensation** and can be severe enough to require pre-treatment with lidocaine. *Etomidate* - **Etomidate**, like propofol, can cause significant pain on injection, although generally less severe than propofol. - The pain is thought to be related to its **propylene glycol vehicle**, which can cause venous irritation. *Methohexital* - **Methohexital**, a barbiturate, is associated with a moderate incidence of **injection site pain and thrombophlebitis**. - Its alkaline pH and direct irritation of the **venous intima** are the primary reasons for patient discomfort during administration.

Question 532: Which IV anesthetic does not cause cardiac depression?

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

Explanation: **Etomidate** - **Etomidate** is known for its **minimal cardiovascular effects**, making it a preferred choice in patients with **pre-existing cardiac disease** or hemodynamic instability. - Unlike other IV anesthetics, it causes very little change in **heart rate**, **blood pressure**, or **cardiac output**. *Propofol* - **Propofol** frequently causes **dose-dependent myocardial depression** and **vasodilation**, leading to significant decreases in blood pressure. - Its cardiovascular effects can be problematic in patients with compromised cardiac function. *Thiopentone* - **Thiopentone**, a barbiturate, typically causes **dose-dependent cardiovascular depression**, including reduced **myocardial contractility** and **vasodilation**. - This can result in a decrease in **blood pressure** and **cardiac output**. *Methohexital* - **Methohexital**, another barbiturate, also causes **cardiovascular depression** similar to thiopentone. - It can lead to decreased **blood pressure** due to both **myocardial depression** and **peripheral vasodilation**.

Question 533: A 45-year-old patient develops bronchospasm during induction. Which inhalational agent is most suitable for management?

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

Explanation: ***Sevoflurane*** - **Sevoflurane** is an excellent choice for managing intraoperative **bronchospasm** due to its low airway irritancy and potent **bronchodilating** properties. - Its rapid onset and offset allow for quick adjustment of anesthetic depth to help relieve airway constriction. *Halothane* - While **halothane** has significant **bronchodilating effects**, its use is limited due to concerns about **hepatotoxicity** (halothane hepatitis) and cardiac arrhythmias. - It is rarely used in modern anesthetic practice, especially when safer alternatives like sevoflurane are available. *Isoflurane* - **Isoflurane** is a **bronchodilator**, but it tends to be more **pungent** and airway irritant than sevoflurane, potentially exacerbating bronchospasm upon induction or during light anesthesia. - It has a slower onset and offset compared to sevoflurane, making it less ideal for rapid resolution of an acute bronchospasm. *Desflurane* - **Desflurane** is a known **airway irritant** and can precipitate or worsen **bronchospasm**, particularly in patients with reactive airway disease, making it unsuitable for this scenario. - Its strong smell and propensity to cause coughing and laryngospasm make it contraindicated during induction in patients at risk for bronchospasm.

Question 534: Which of the following is used as an adjuvant during anesthesia?

A. Bupivacaine
B. Dexmedetomidine (Correct Answer)
C. Lorazepam
D. Neostigmine

Explanation: ***Dexmedetomidine*** - **Dexmedetomidine** is an alpha-2 adrenergic agonist commonly used as an **adjuvant** in anesthesia to provide **sedation**, **analgesia**, and **anxiolysis** with minimal respiratory depression. - Its unique properties allow for cooperative sedation, where patients can be aroused and follow commands, making it useful in various anesthetic settings. *Bupivacaine* - **Bupivacaine** is a **local anesthetic** used for regional anesthesia and pain management, not typically as an adjuvant to achieve general anesthetic effects. - It primarily blocks nerve impulse transmission to numb specific areas, rather than contributing to overall anesthetic depth or sedation. *Lorazepam* - **Lorazepam** is a **benzodiazepine** primarily used for **anxiolysis** and **sedation** prior to anesthesia or for treatment of anxiety. - While it can be given before surgery, it is not an anesthetic adjuvant in the same way dexmedetomidine is used during the operative phase to modulate anesthetic requirements and recovery. *Neostigmine* - **Neostigmine** is an **acetylcholinesterase inhibitor** used to **reverse the effects of non-depolarizing neuromuscular blockers** at the end of surgery. - It does not induce anesthesia, sedation, or analgesia, but rather restores muscle function to allow for extubation.

Question 535: Purpose of giving Glycopyrrolate before GA

A. Decrease laryngeal secretions (Correct Answer)
B. Provides analgesia
C. Prevents aspiration
D. Muscle relaxation

Explanation: ***Decrease laryngeal secretions*** - Glycopyrrolate is an **anticholinergic** agent that primarily reduces salivary, tracheobronchial, and pharyngeal secretions. - This action helps to prevent accumulation of secretions, which can interfere with airway management and increase the risk of **laryngospasm** during induction of general anesthesia. *Provides analgesia* - Glycopyrrolate has **no analgesic properties** and does not reduce pain. - Its mechanism of action is limited to blocking muscarinic acetylcholine receptors, which does not impact pain pathways. *Prevents aspiration* - While reducing secretions might indirectly lower aspiration risk, glycopyrrolate does **not directly prevent aspiration** by improving gastric emptying or sphincter tone. - Other medications, such as H2 blockers or proton pump inhibitors, are more effective for aspiration prophylaxis related to gastric contents. *Muscle relaxation* - Glycopyrrolate is **not a muscle relaxant** and does not act at the neuromuscular junction. - Muscle relaxation for general anesthesia is provided by **neuromuscular blocking agents** like rocuronium or succinylcholine.

Question 536: Patient was planned for surgery under GA, in the induction phase rocuronium was given 85mg but the anesthetist did not succeed in intubating. Which could be the best reversal agent used?

A. Neostigmine (non-specific acetylcholinesterase inhibitor)
B. Glycopyrrolate (anticholinergic agent)
C. Edrophonium (non-specific acetylcholinesterase inhibitor)
D. Sugammadex (specific reversal agent for rocuronium) (Correct Answer)

Explanation: ***Sugammadex (specific reversal agent for rocuronium)*** - **Sugammadex** is a modified gamma-cyclodextrin that forms a tight, water-soluble complex with **rocuronium**, effectively encapsulating and inactivating it. - It is highly effective for rapid reversal of **rocuronium**-induced neuromuscular blockade, especially in situations where immediate reversal is critical, such as a "cannot intubate, cannot ventilate" scenario. *Neostigmine (non-specific acetylcholinesterase inhibitor)* - **Neostigmine** acts by inhibiting **acetylcholinesterase**, increasing the amount of acetylcholine at the neuromuscular junction to overcome the competitive block. - Its reversal effect is slower and less reliable than sugammadex, especially after a large dose of rocuronium or deep blockade. *Glycopyrrolate (anticholinergic agent)* - **Glycopyrrolate** is an **anticholinergic** agent used to counteract the muscarinic side effects (e.g., bradycardia, salivation) of **acetylcholinesterase inhibitors** like neostigmine, but it has no direct reversal effect on neuromuscular blockade. - It is typically co-administered with neostigmine, not used as a standalone reversal agent for **rocuronium**. *Edrophonium (non-specific acetylcholinesterase inhibitor)* - **Edrophonium** is a short-acting **acetylcholinesterase inhibitor**, similar to neostigmine but with a more rapid onset and shorter duration of action. - It is less potent and effective than neostigmine for reversing moderate to deep neuromuscular blockade and would not be the best choice after a significant dose of **rocuronium**.

Question 537: A patient with liver cirrhosis is scheduled for surgery. Which anesthetic agent should be avoided?

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

Explanation: ***Halothane*** - **Halothane** metabolism produces **trifluoroacetylated proteins**, which can lead to severe **hepatotoxicity**, a critical concern in patients with pre-existing liver disease like cirrhosis. - Its use can exacerbate liver dysfunction due to its **extensive hepatic metabolism** compared to newer volatile anesthetics. *Sevoflurane* - **Sevoflurane** undergoes minimal hepatic metabolism (around 3-5%) and is primarily eliminated via the lungs, making it a safer option for patients with liver disease. - It has a good safety profile with a low incidence of hepatotoxicity. *Propofol* - **Propofol** is primarily metabolized in the liver, but its high hepatic clearance and non-cumulative nature make it suitable for patients with liver cirrhosis, although dosage adjustments may be necessary. - It does not produce toxic metabolites that significantly harm the liver. *Isoflurane* - **Isoflurane** is very minimally metabolized by the liver (around 0.2%), with the majority eliminated unchanged via the lungs. - This low hepatic metabolic load makes it a safe choice for patients with liver impairment.

Question 538: Which drug is used to reverse the effects of non-depolarizing muscle relaxants?

A. Atropine
B. Neostigmine (Correct Answer)
C. Glycopyrrolate
D. Edrophonium

Explanation: ***Neostigmine*** - **Neostigmine** is an **acetylcholinesterase inhibitor** that increases the amount of acetylcholine at the neuromuscular junction. - This increased acetylcholine can then compete with **non-depolarizing muscle relaxants** for receptors, reversing their effects. *Atropine* - **Atropine** is an **anticholinergic drug** that blocks muscarinic receptors. - It is often co-administered with neostigmine to counteract the **parasympathetic side effects** of neostigmine, such as bradycardia and increased salivation, but does not reverse muscle relaxation directly. *Glycopyrrolate* - **Glycopyrrolate** is also an **anticholinergic drug** similar to atropine, but with less central nervous system penetration. - It is co-administered with neostigmine for the same reason as atropine, to mitigate the **cholinergic side effects** of neostigmine, not to reverse muscle paralysis. *Edrophonium* - **Edrophonium** is a short-acting **acetylcholinesterase inhibitor** historically used to reverse non-depolarizing muscle relaxants. - While it can reverse muscle relaxation, it has a **shorter duration of action** compared to neostigmine and is less commonly used for this purpose in modern practice.

Question 539: A 45-year-old patient undergoing surgery develops tachycardia and hyperthermia intraoperatively. Which agent should be avoided in future anesthetics for this patient?

A. Desflurane (Correct Answer)
B. Thiopental
C. Fentanyl
D. Etomidate

Explanation: ***Desflurane*** - The development of intraoperative **tachycardia** and **hyperthermia** is highly suggestive of **malignant hyperthermia (MH)**, a genetic disorder triggered by volatile anesthetic agents and succinylcholine. - **Desflurane** is a volatile anesthetic and a known trigger for MH, thus it should be avoided in future anesthetics for this patient. *Thiopental* - **Thiopental** is a short-acting barbiturate used for induction of anesthesia, and it is **not a trigger for malignant hyperthermia**. - It would be considered a safe alternative for future anesthetics in a patient susceptible to MH. *Fentanyl* - **Fentanyl** is an opioid analgesic commonly used during anesthesia; it is **not a triggering agent for malignant hyperthermia**. - Opioids are generally safe to use in patients with a history of MH. *Etomidate* - **Etomidate** is an intravenous anesthetic agent primarily used for induction, and it is **not associated with malignant hyperthermia**. - It presents a safe option for induction in patients with a history of MH.

Question 540: Which of the following is a contraindication for the use of succinylcholine?

A. Low calcium levels (hypocalcemia)
B. Susceptibility to malignant hyperthermia (Correct Answer)
C. Severe cases of myasthenia gravis
D. High potassium levels (severe hyperkalemia)

Explanation: ***Susceptibility to malignant hyperthermia*** - Succinylcholine, a **depolarizing neuromuscular blocker**, is a potent trigger for **malignant hyperthermia** in susceptible individuals. - Malignant hyperthermia is a life-threatening, **hypermetabolic crisis** characterized by muscle rigidity, hyperthermia, tachycardia, and acidosis. *Severe cases of myasthenia gravis* - Patients with myasthenia gravis, an **autoimmune disorder affecting neuromuscular junctions**, are generally more sensitive to depolarizing and non-depolarizing neuromuscular blockers. - While caution is advised, it is not an absolute contraindication but rather requires **reduced doses** and careful monitoring to avoid prolonged blockade. *High potassium levels (severe hyperkalemia)* - Succinylcholine causes a transient **increase in serum potassium levels** due to the efflux of potassium from muscle cells. - In patients with pre-existing severe hyperkalemia, this can lead to **life-threatening arrhythmias** or cardiac arrest, making it a relative contraindication. *Low calcium levels (hypocalcemia)* - Hypocalcemia can potentially **potentiate the effects of neuromuscular blockers**, but it is not typically considered a direct contraindication for succinylcholine use. - The primary concern with succinylcholine relates to potassium efflux and its triggers for malignant hyperthermia.

Practice by Chapter

History of Anesthesia

Practice Questions

Preoperative Evaluation

Practice Questions

Pharmacology of Inhalational Anesthetics

Practice Questions

Pharmacology of Intravenous Anesthetics

Practice Questions

Neuromuscular Blocking Agents

Practice Questions

Airway Management

Practice Questions

Endotracheal Intubation

Practice Questions

Difficult Airway Algorithms

Practice Questions

Intraoperative Monitoring

Practice Questions

Depth of Anesthesia Monitoring

Practice Questions

Emergence from Anesthesia

Practice Questions

Postoperative Care

Practice Questions

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