General Anesthesia Practice Questions

Q: Which of the following is/are hepatotoxic anesthetic agent(s)?

Both Chloroform and Halothane. ***Both Chloroform and Halothane*** - Both agents are well-established hepatotoxins used historically in anesthesia - **Chloroform** causes direct hepatotoxicity through centrilobular necrosis due to reactive metabolites (CYP2E1-mediated) - **Halothane** causes halothane hepatitis, a rare but potentially fatal immune-mediated hepatotoxicity (occurs in 1:10,000-35,000 exposures) - This is the **most complete answer** as it includes all hepatotoxic agents listed *Halothane* - This is medically correct - halothane is indeed hepatotoxic - However, this is **incomplete** as it omits chloroform, another hepatotoxic anesthetic agent in the options - When multiple correct agents are listed, the most comprehensive answer is preferred *Chloroform* - This is medically correct - chloroform is indeed hepatotoxic - However, this is **incomplete** as it omits halothane, another hepatotoxic anesthetic agent in the options - Chloroform was historically used but abandoned due to hepatotoxicity and cardiac arrhythmias *None of the above* - This is incorrect as both chloroform and halothane have well-documented hepatotoxic effects - Both agents can cause liver damage ranging from transient enzyme elevation to fulminant hepatic failure

Q: What is the intubation dose of pancuronium?

0.08 mg/Kg. ***0.08 mg/Kg*** - The standard **intubating dose** of pancuronium is typically **0.08-0.1 mg/kg intravenously**. - This dose provides adequate **neuromuscular blockade** for endotracheal intubation. *0.02 mg/Kg* - This dose is too low and would likely result in **insufficient neuromuscular blockade** for successful intubation. - Sub-therapeutic doses would lead to **incomplete muscle relaxation**, making intubation difficult and risky. *0.04 mg/Kg* - While higher than 0.02 mg/kg, this dose is still generally considered **sub-optimal** for intubation with pancuronium. - It may prolong the onset of action or provide **inadequate depth of block** for optimal intubating conditions. *0.06 mg/Kg* - This dose is approaching the lower end of an effective range for some neuromuscular blocking agents, but it is typically **not sufficient** for reliable intubation with pancuronium. - It might lead to a longer **onset time** and compromised intubating conditions compared to the recommended dose.

Q: Second gas effect is exaggerated by which of the following gases when co-administered with halothane?

Nitrous oxide. ***Nitrous oxide*** - **Nitrous oxide** has a high partial pressure and low blood solubility, leading to its rapid uptake into the blood and then into the alveoli. - This rapid absorption concentrates the remaining inspired gases, including halothane, thereby exacerbating the **second gas effect** and leading to a more rapid increase in halothane's partial pressure in the alveoli. *Cyclopropane* - While cyclopropane is an anesthetic gas with quick induction, it is no longer widely used and its physiological interaction with other gases in exaggerating the second gas effect is not as pronounced or clinically relevant as that of nitrous oxide. - It has a low MAC and high potency, but its role in the **second gas effect** is not primarily due to its rapid tissue uptake and concentration of other gases in the same manner as nitrous oxide. *Nitrogen (inert gas)* - Nitrogen is an **inert gas** and does not readily participate in physiological processes or anesthetic effects. - Its presence in the inspired gas mixture does not significantly affect the uptake of other anesthetic gases to exaggerate the **second gas effect**. *Helium (low solubility)* - Helium has very **low blood solubility** but is not an anesthetic gas. - Although its low solubility might suggest rapid movement, it would not concentrate other anesthetic gases or directly contribute to the **second gas effect** in the manner of nitrous oxide, which is itself an anesthetic agent with high partial pressure.

Q: Which of the following intravenous agents is known to cause pain upon injection?

Propofol. ***Propofol*** - **Propofol** is notoriously known to cause significant **pain upon injection**, especially when administered into smaller veins. - This is attributed to its **lipid emulsion formulation** and activation of **TRPA1 receptors** on sensory neurons. *Methohexital* - While **methohexital** can cause localized pain and venous irritation, it is generally less pronounced and less frequent than with propofol. - It is known more for causing **hiccups** and **muscle twitching** upon induction, rather than severe injection pain. *Ketamine* - **Ketamine** typically causes minimal to no pain upon intravenous injection. - Its side effects are often related to its **dissociative anesthetic** properties, such as psychomimetic effects and increased sympathetic activity. *Etomidate* - **Etomidate** is generally considered to be low in causing injection site pain. - Its primary concern is the potential for **adrenocortical suppression** and a high incidence of **myoclonus**.

Q: Which organ is most resistant to general anesthesia?

Heart. ***Heart*** - The heart is highly resistant to the direct suppressive effects of **general anesthetics** because its primary function is to maintain circulation, and it has intrinsic automaticity. - While anesthetic agents can influence heart rate and contractility, the heart itself continues to function even at deep anesthetic planes, unlike the brain or spinal cord which are targets of anesthesia. *Spinal Cord* - The spinal cord is particularly sensitive to general anesthetics, as they are crucial in producing the immobility component of anesthesia by **depressing spinal reflexes**. - High concentrations of anesthetics can directly suppress spinal cord activity, leading to muscle relaxation and loss of motor response. *Medulla oblongata* - The medulla oblongata contains vital centers for **respiration** and **cardiovascular control** that are highly sensitive to anesthetic agents. - Anesthetic overdose can lead to profound depression of these centers, resulting in respiratory arrest and severe cardiovascular collapse due to direct effects on neurons located there. *Liver* - The liver is primarily involved in the **metabolism of many anesthetic drugs**, rather than being a direct target for their central depressant effects. - While anesthetic agents can impact hepatic blood flow and function, the liver itself does not exhibit the same level of resistance to the *direct pharmacological effects* of anesthesia as the heart.

Q: Which of the following determines the speed of recovery from intravenous anesthesia?

Redistribution of the drug from sites in the CNS. ***Redistribution of the drug from sites in the CNS*** - For many intravenous anesthetic agents, **redistribution** from highly perfused central nervous system (CNS) tissues to less perfused peripheral tissues is the primary mechanism for the termination of drug action and recovery from anesthesia. - This rapid decrease in the drug concentration at the site of action (brain) leads to the patient waking up, even before significant metabolism or excretion has occurred. *Liver metabolism of drug* - While liver metabolism is crucial for the **elimination** of many anesthetic drugs from the body, it is typically a slower process and contributes more to the overall drug clearance than to the immediate termination of the anesthetic effect. - Significant metabolism usually occurs after redistribution has already caused the patient to awaken. *Protein binding of drug* - **Protein binding** affects the free fraction of the drug available to act on receptors and to be metabolized or excreted. - However, it does not directly determine the speed of recovery, which is more dependent on the drug's movement between tissue compartments. *Plasma clearance of the drug* - **Plasma clearance** refers to the volume of plasma cleared of the drug per unit time, encompassing both metabolism and excretion. - While important for overall drug removal, it is generally a slower process compared to redistribution in determining the immediate end of intravenous anesthetic action.

Q: What is the percentage of halothane that is metabolized in the human body?

25%. **Correct: 25%** - Approximately **25%** of administered halothane is metabolized in the liver, which is a relatively high percentage compared to other volatile anesthetics. - This extensive metabolism can lead to the formation of reactive intermediates, contributing to its potential for **hepatotoxicity** (halothane hepatitis). *Incorrect: 50%* - **50%** metabolism is significantly higher than what is observed for halothane and would imply even greater risk of significant metabolic byproduct accumulation and toxicity. - Most volatile anesthetics are metabolized to a much lesser extent, with desflurane having the least metabolism (<0.02%). *Incorrect: 5%* - **5%** metabolism is too low for halothane; while some volatile anesthetics like isoflurane fall into this range (~0.2-2%), halothane is known for its considerably higher metabolic rate. - A 5% metabolism rate would result in less concern for and incidence of **halothane hepatitis**. *Incorrect: 2.50%* - **2.50%** metabolism is an underestimation of halothane's metabolic activity within the body. - Anesthetic agents such as **enflurane** have a metabolism rate closer to this value (~2-5%), whereas halothane is much higher.

Q: Which of the following should be considered as the cause of generalized convulsions 20 minutes postoperatively?

Enflurane. ***Enflurane*** - **Enflurane** is well-known to cause **generalized convulsions** or seizure-like activity during emergence from anesthesia, particularly when inspired concentrations exceed 3.0% or with hypocapnia. - The risk of seizures is a significant reason why enflurane is rarely used in modern anesthetic practice compared to newer volatile agents. *Halothane* - **Halothane** is associated with cardiac arrhythmias and hepatotoxicity but generally does not cause generalized convulsions as a primary side effect. - While it can lower the seizure threshold, overt seizures are not a common complication of halothane administration. *Isoflurane* - **Isoflurane** is associated with CNS depression and can, in rare cases, cause myoclonus, but it is not typically linked to generalized tonic-clonic convulsions. - It is often used in neurosurgery due to its beneficial effects on cerebral blood flow and minimal seizure-inducing potential. *Sevoflurane* - **Sevoflurane**, while capable of causing excitatory movements or myoclonus during induction and emergence, is not a common cause of clear-cut generalized convulsions in healthy patients. - High concentrations in pediatric patients or those with pre-existing seizure disorders might slightly increase the risk of seizure-like EEG changes, but it is less epileptogenic than enflurane.

Q: Ketamine is the preferred anesthetic for the following conditions except:

Hypertensives. ***Hypertensives*** - Ketamine can cause a significant **increase in blood pressure and heart rate** due to its sympathomimetic effects. - This makes it a less desirable agent for patients with **uncontrolled hypertension**, as it could exacerbate their condition. *Trauma cases that have bled significantly* - Ketamine is preferred in trauma patients with significant blood loss because it **maintains cardiovascular stability** by increasing heart rate and blood pressure, which helps preserve organ perfusion. - Its **sympathomimetic properties** counteract the hypotensive effects of hypovolemia, making it beneficial in these critical situations. *Burn dressing* - Ketamine is well-suited for painful procedures like burn dressing changes because it provides **potent analgesia and amnesia** while largely preserving airway reflexes. - Its ability to maintain **hemodynamic stability** and respiratory function is advantageous for patients undergoing repeated painful interventions. *Short operations on asthmatics* - Ketamine is a good choice for asthmatic patients because it has **bronchodilatory properties**, which can help prevent or ameliorate bronchospasm. - It also **preserves respiratory drive** and airway reflexes, making it safer for patients with reactive airway disease undergoing short procedures.

Q: Which anesthetic agent is considered the least cardiotoxic?

Sevoflurane. ***Sevoflurane*** - Sevoflurane is known for its **smooth induction** and rapid recovery, making it a common choice, especially in pediatric anesthesia [3]. - It has a relatively **low pungency** and minimal cardiovascular depressant effects compared to other volatile anesthetics, contributing to its favorable cardiotoxicity profile [1], [4]. *Enflurane* - Enflurane can cause **myocardial depression** and may induce **seizures** at higher concentrations, limiting its use [1]. - Its widespread use has decreased due to concerns about its **cardiovascular effects** and potential for **renal toxicity**. *Isoflurane* - While Isoflurane is a commonly used anesthetic, it can cause **coronary steal phenomenon** in patients with coronary artery disease due to its potent vasodilatory effects. - It also causes dose-dependent **myocardial depression** and can increase heart rate, which may be detrimental in some patients [4]. *Halothane* - Halothane is known for significant **myocardial depression**, causing a decrease in cardiac output and systemic vascular resistance [2]. - It also sensitizes the myocardium to **catecholamines**, increasing the risk of arrhythmias, and is associated with **halothane hepatitis**, a rare but severe liver injury [3].

Question 1

Which of the following is/are hepatotoxic anesthetic agent(s)?

Accepted Answer

Both Chloroform and Halothane

Answer

Halothane

Answer

None of the above

Answer

Chloroform

Question 2

What is the intubation dose of pancuronium?

Accepted Answer

0.08 mg/Kg

Answer

0.02 mg/Kg

Answer

0.04 mg/Kg

Answer

0.06 mg/Kg

Question 3

Second gas effect is exaggerated by which of the following gases when co-administered with halothane?

Accepted Answer

Nitrous oxide

Answer

Cyclopropane

Answer

Nitrogen (inert gas)

Answer

Helium (low solubility)

Question 4

Which of the following intravenous agents is known to cause pain upon injection?

Accepted Answer

Propofol

Answer

Ketamine

Answer

Etomidate

Answer

Methohexital

Question 5

Which organ is most resistant to general anesthesia?

Accepted Answer

Heart

Answer

Spinal Cord

Answer

Medulla oblongata

Answer

Liver

Question 6

Which of the following determines the speed of recovery from intravenous anesthesia?

Accepted Answer

Redistribution of the drug from sites in the CNS

Answer

Liver metabolism of drug

Answer

Protein binding of drug

Answer

Plasma clearance of the drug

Question 7

What is the percentage of halothane that is metabolized in the human body?

Accepted Answer

25%

Answer

50%

Answer

5%

Answer

2.50%

Question 8

Which of the following should be considered as the cause of generalized convulsions 20 minutes postoperatively?

Accepted Answer

Enflurane

Answer

Halothane

Answer

Isoflurane

Answer

Sevoflurane

Question 9

Ketamine is the preferred anesthetic for the following conditions except:

Accepted Answer

Hypertensives

Answer

Trauma cases that have bled significantly

Answer

Burn dressing

Answer

Short operations on asthmatics

Question 10

Which anesthetic agent is considered the least cardiotoxic?

Accepted Answer

Sevoflurane

Answer

Isoflurane

Answer

Enflurane

Answer

Halothane

General Anesthesia — MCQs

General Anesthesia — MCQs

On this page

Practice by Chapter

Want unlimited practice?