General Anesthesia Practice Questions

Q: Dissociative anaesthesia is produced by?

Ketamine. ***Ketamine*** - **Ketamine** is a unique anesthetic that produces a state of **dissociative anesthesia**, characterized by a trance-like state, analgesia, amnesia, and catalepsy. - This effect is primarily due to its antagonism of the **N-methyl-D-aspartate (NMDA) receptor**. *Etomidate* - **Etomidate** is an intravenous anesthetic characterized by its **cardiovascular stability**, making it suitable for patients with heart conditions. - It works primarily by modulating **GABA-A receptors** but does not produce dissociative anesthesia. *Propofol* - **Propofol** is a widely used intravenous anesthetic known for its **rapid onset and recovery**, and it is often used for induction and maintenance of general anesthesia. - Its primary mechanism of action involves enhancing the effects of **GABA-A receptors**, leading to central nervous system depression, but not dissociative anesthesia. *Thiopentone* - **Thiopentone** (Thiopental) is a barbiturate anesthetic that causes rapid loss of consciousness and has been historically used for inducing general anesthesia. - It acts as a **GABA-A receptor agonist**, depressing the central nervous system, but it does not produce the distinct dissociative state seen with ketamine.

Q: Which inhalational agent has the least MAC?

Halothane. ***Halothane*** - **Halothane** has a **MAC** of approximately **0.75%**, which is among the lowest for commonly used volatile anesthetics. - A lower **MAC** indicates a higher potency, meaning a lower concentration is needed to achieve anesthetic effect. *Xenon* - **Xenon** has a **MAC** of approximately **71%**, making it one of the least potent inhalational agents. - It is an inert gas with unique anesthetic properties, but its high **MAC** is a key characteristic. *Sevoflurane* - **Sevoflurane** has a **MAC** of approximately **2.0%**, which is higher than halothane. - It is known for its rapid onset and offset due to its low blood solubility. *Isoflurane* - **Isoflurane** has a **MAC** of approximately **1.15%**, which is higher than halothane. - It is often favored for its cardiovascular stability and relatively low metabolism.

Q: Which anesthetic agent is known for the fastest induction and recovery?

N2O. ***N2O*** - **Nitrous oxide** has a very **low blood-gas partition coefficient** (0.47), meaning it quickly saturates the blood and brain, leading to rapid induction and recovery. - Its **low solubility** allows for fast changes in anesthetic depth as it moves rapidly in and out of the bloodstream. *Desflurane* - While Desflurane also has a **low blood-gas partition coefficient** (0.42) and provides rapid induction and recovery, **N2O** is generally recognized as having the fastest kinetics. - Desflurane's volatility often requires a specialized heated vaporizer due to its **low boiling point**. *Halothane* - Halothane has a **higher blood-gas partition coefficient** (2.4) compared to N2O and desflurane, resulting in a slower induction and recovery time. - It is associated with potential **hepatotoxicity** (halothane hepatitis) and is no longer widely used. *Enflurane* - Enflurane has an intermediate **blood-gas partition coefficient** (1.9), making its induction and recovery slower than N2O, desflurane, and sevoflurane. - It can cause **seizures** at high concentrations and is also largely replaced by newer agents.

Q: Who coined the term "balanced anaesthesia"?

Lundy (John S. Lundy). ***Lundy (John S. Lundy)*** - **John S. Lundy** is credited with coining the term "**balanced anaesthesia**" in the early 20th century. - This concept describes the use of **multiple anesthetic agents** in combination, each contributing to different aspects of anesthesia (e.g., hypnosis, analgesia, muscle relaxation). *Simpson* - **Sir James Young Simpson** was a Scottish physician who pioneered the use of **chloroform** and ether as anesthetics in the mid-19th century. - While he significantly advanced the field of anesthesia, he did not coin the term "balanced anaesthesia." *Fischer* - **Emil Fischer** was a German chemist who won the Nobel Prize in Chemistry for his work on sugar and purine syntheses. - His contributions were primarily in organic chemistry and biochemistry, not directly in the field of clinical anesthesia terminology. *Morton* - **William T.G. Morton** was an American dentist who famously demonstrated the first public use of **ether** for surgical anesthesia in 1846. - He is known for popularizing ether as a surgical anesthetic but did not coin the term "balanced anaesthesia."

Q: Who was the first to use ether as an anesthetic?

William T.G. Morton. ***William T.G. Morton*** - **William T.G. Morton** was a dentist who publicly demonstrated the use of **ether** as a surgical anesthetic in 1846 during a tooth extraction and later for a tumor removal at Massachusetts General Hospital. - His pioneering work popularized the use of ether, revolutionizing surgical practices by allowing pain-free procedures. *John Snow* - **John Snow** was an English physician known for his work in public health, particularly for tracing the source of a **cholera outbreak** in London. - He is remembered as one of the founders of **modern epidemiology**, not for anesthetic discoveries. *James Simpson* - **James Simpson** was a Scottish obstetrician who pioneered the use of **chloroform** as an anesthetic in obstetrics and surgery, not ether. - He advocated for its use to alleviate pain during childbirth, facing initial controversy. *Joseph Lister* - **Joseph Lister** was a British surgeon who introduced **antiseptic surgery**, significantly reducing post-operative infections. - He is known for promoting the use of **carbolic acid** to sterilize instruments and wounds, not for anesthetic development.

Q: Which anesthetic agent is known for providing smooth induction?

Isoflurane. ***Isoflurane*** - **Isoflurane** is frequently chosen for its capacity to induce a **smooth and rapid loss of consciousness**, primarily due to its low blood solubility which facilitates quick changes in anesthetic depth. - Its **minimal irritation** to the respiratory tract and **stable cardiovascular profile** during induction contribute to a smoother process for the patient. *Sevoflurane* - While sevoflurane also offers a **smooth and rapid induction** due to its low solubility, it is sometimes associated with a higher incidence of **airway irritation** (e.g., coughing) compared to isoflurane, especially in children. - It is known for its **pleasant odor**, making it a good choice for mask induction in pediatric patients. *Halothane* - **Halothane** provides a relatively smooth induction but has a higher risk of **hepatotoxicity** and cardiac arrhythmias, which have led to its decreased use. - Its higher blood solubility means a **slower onset and offset** compared to modern volatile agents like isoflurane. *Enflurane* - **Enflurane** can cause **CNS excitation** at deeper levels of anesthesia, potentially leading to seizures, making its induction less smooth and predictable. - It also has a greater potential to cause **myocardial depression** and arrhythmias than isoflurane.

Q: Which of the following anesthetic agents is most notable for its analgesic properties?

Ketamine. ***Ketamine*** - **Ketamine** is unique among general anesthetics for its significant **analgesic properties**, which stem from its action as an **NMDA receptor antagonist**. - Its ability to provide pain relief makes it useful in scenarios where both **anesthesia** and **analgesia** are desired, such as for painful procedures or in trauma settings. *Propofol* - While **propofol** is a widely used intravenous anesthetic, it lacks intrinsic **analgesic properties**. Its primary effects are **sedation** and **hypnosis**. - Pain during propofol injection is common, and other analgesics are usually co-administered for painful procedures. *Thiopentone* - **Thiopentone** is an ultrashort-acting barbiturate primarily used for **induction of anesthesia** due to its rapid onset and profound hypnotic effects. - It has **no analgesic properties** and can even lower the pain threshold, requiring concurrent administration of analgesics.

Q: Which inhalational anesthetic agent is known to be hepatotoxic?

Halothane. ***Halothane*** - Halothane is historically known for causing **halothane hepatitis**, a severe and sometimes fatal liver injury. - This toxicity is thought to be due to its metabolism to **trifluoroacetyl (TFA) halides**, which can bind to hepatocyte proteins, leading to an immune reaction. *Enflurane* - Enflurane can cause a small amount of **nephrotoxicity** due to fluoride ion production, but it is not typically associated with significant hepatotoxicity. - Its metabolism is limited, resulting in lower fluoride levels compared to older agents but still can be a concern in patients with renal impairment. *Desflurane* - Desflurane is minimally metabolized and is considered one of the safest inhalational agents in terms of organ toxicity. - Due to its low solubility and rapid elimination, it has a very low risk of causing **organ damage**, including the liver. *Sevoflurane* - Sevoflurane is generally considered safe for the liver and is widely used, particularly in pediatric anesthesia. - While it undergoes some metabolism to fluoride ions, it is not associated with significant **hepatotoxicity** in clinical practice, though it can interact with desiccated CO2 absorbents to produce Compound A.

Q: Which of the following anesthetics is known to increase intraocular pressure?

Ketamine. ***Ketamine*** - **Ketamine** is known to increase **intraocular pressure (IOP)**, making it generally avoided in patients with **glaucoma** or those undergoing ocular surgery. - This effect is due to its influence on sympathetic nervous system activity and extraocular muscle tone. *Thiopental* - **Thiopental**, a barbiturate, typically causes a **reduction in intraocular pressure**, which can be beneficial in certain ocular procedures. - Its mechanism involves decreasing cerebral blood flow and metabolic rate, indirectly leading to a decrease in IOP. *Alfentanil* - **Alfentanil**, an opioid, generally has **minimal to no significant effect on intraocular pressure**. - Its primary actions are analgesia and sedation, without direct impact on oculomotor tone or fluid dynamics. *Propofol* - **Propofol** is known to **decrease intraocular pressure**, making it a favorable agent for ophthalmic surgery. - This effect is attributed to a reduction in cerebral blood flow and an inhibition of aqueous humor production.

Q: Which inhalational anesthetic has the highest global warming potential?

Desflurane. ***Desflurane*** - **Desflurane** has the highest global warming potential among commonly used volatile anesthetics due to its high **infrared absorbance** and long **atmospheric lifetime**. - Its environmental impact is a recognized concern, leading to efforts to reduce its use in clinical practice. *Isoflurane* - **Isoflurane** has a lower global warming potential and atmospheric lifetime compared to **desflurane**. - While it contributes to greenhouse gas emissions, its impact is less significant than desflurane. *Sevoflurane* - **Sevoflurane** has the lowest global warming potential and the shortest atmospheric lifetime among the modern volatile anesthetics. - It is often considered a more **environmentally friendly** option compared to desflurane and isoflurane. *Halothane* - **Halothane** is an older inhalational anesthetic that is rarely used today due to concerns about **hepatotoxicity** and **cardiac arrhythmias**. - Although it has ozone-depleting potential due to its chlorine content, its global warming potential is less than desflurane and its clinical use is negligible.

Question 1

Dissociative anaesthesia is produced by?

Accepted Answer

Ketamine

Answer

Etomidate

Answer

Propofol

Answer

Thiopentone

Question 2

Which inhalational agent has the least MAC?

Accepted Answer

Halothane

Answer

Xenon

Answer

Sevoflurane

Answer

Isoflurane

Question 3

Which anesthetic agent is known for the fastest induction and recovery?

Accepted Answer

N2O

Answer

Halothane

Answer

Enflurane

Answer

Desflurane

Question 4

Who coined the term "balanced anaesthesia"?

Accepted Answer

Lundy (John S. Lundy)

Answer

Simpson

Answer

Fischer

Answer

Morton

Question 5

Who was the first to use ether as an anesthetic?

Accepted Answer

William T.G. Morton

Answer

John Snow

Answer

James Simpson

Answer

Joseph Lister

Question 6

Which anesthetic agent is known for providing smooth induction?

Accepted Answer

Isoflurane

Answer

Halothane

Answer

Enflurane

Answer

Sevoflurane

Question 7

Which of the following anesthetic agents is most notable for its analgesic properties?

Accepted Answer

Ketamine

Answer

Thiopentone

Answer

Propofol

Answer

None of the options

Question 8

Which inhalational anesthetic agent is known to be hepatotoxic?

Accepted Answer

Halothane

Answer

Enflurane

Answer

Desflurane

Answer

Sevoflurane

Question 9

Which of the following anesthetics is known to increase intraocular pressure?

Accepted Answer

Ketamine

Answer

Thiopental

Answer

Alfentanil

Answer

Propofol

Question 10

Which inhalational anesthetic has the highest global warming potential?

Accepted Answer

Desflurane

Answer

Isoflurane

Answer

Sevoflurane

Answer

Halothane

General Anesthesia — MCQs

General Anesthesia — MCQs

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