General Anesthesia Practice Questions

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 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: Regarding propofol, which one of the following statements is false?

It causes severe vomiting. ***It causes severe vomiting*** - Propofol is actually known for its **antiemetic properties**, meaning it helps *prevent* rather than cause nausea and vomiting. - This makes it a preferred anesthetic for procedures where **postoperative nausea and vomiting (PONV)** are a concern. *It is used as an intravenous induction agent* - **Propofol** is a widely used **intravenous anesthetic** for the **induction and maintenance of general anesthesia**. - It provides a rapid onset of unconsciousness due to its high lipid solubility. *It is painful on injecting intravenously* - Injection of propofol can often cause **pain at the injection site**, particularly when administered into smaller veins. - This pain can be mitigated by co-administering **lidocaine** or using larger veins. *It has no muscle relaxant property* - Propofol does **not possess intrinsic muscle relaxant properties**; patients require additional neuromuscular blocking agents for surgical relaxation. - It facilitates intubation by causing **loss of consciousness** and **reducing airway reflexes**, but does not directly relax skeletal muscles.

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.

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: 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 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 anaesthetic drug contributes to green house effect?

Desflurane. **Desflurane** - **Desflurane** has the highest **global warming potential (GWP)** among commonly used volatile anesthetics, primarily due to its long atmospheric half-life and potent infrared absorption. - Its environmental impact is also amplified by its high **minimum alveolar concentration (MAC)** and low blood solubility, requiring higher delivered concentrations for anesthesia. *Enflurane* - **Enflurane** has a lower GWP compared to desflurane and is less commonly used in modern practice. - While it contributes to the greenhouse effect, its impact is significantly less than that of desflurane due to differences in chemical structure and atmospheric persistence. *Sevoflurane* - **Sevoflurane** has a relatively low GWP and a short atmospheric half-life compared to desflurane, making it a more environmentally friendly option among volatile anesthetics. - Although it still contributes to atmospheric warming, its overall environmental impact is considerably less than desflurane's. *Halothane* - **Halothane** is a potent greenhouse gas but is no longer used in many parts of the world due to concerns about hepatotoxicity and its significant ozone-depleting potential. - While it contributes to atmospheric warming, its current lack of clinical use limits its ongoing contribution to the greenhouse effect compared to currently utilized agents.

Q: Intraocular pressure is increased by which anaesthetic?

Ketamine. ***Ketamine*** - **Ketamine** is known to increase **intraocular pressure (IOP)**, making it generally avoided in patients with glaucoma or penetrating eye injuries. - This effect is thought to be due to its dissociative properties, causing **nystagmus**, and stimulating extraocular muscles. *Nitrous Oxide* - **Nitrous oxide** by itself has minimal or no direct effect on **intraocular pressure (IOP)**. - However, in cases of an air-filled globe (e.g., after retinal detachment surgery), it can increase IOP by expanding the gas bubble. *Isoflurane* - **Isoflurane**, like most volatile anesthetics, typically **decreases intraocular pressure (IOP)**. - This reduction is generally due to its effects on reducing aqueous humor production and increasing uveoscleral outflow. *Propofol* - **Propofol** is known for its ability to **decrease intraocular pressure (IOP)**. - This effect is mediated by a reduction in aqueous humor production and an increase in uveoscleral outflow, making it a favorable choice in ophthalmic surgery.

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.

Question 1

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 2

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

Accepted Answer

Ketamine

Answer

Thiopental

Answer

Alfentanil

Answer

Propofol

Question 3

Regarding propofol, which one of the following statements is false?

Accepted Answer

It causes severe vomiting

Answer

It is painful on injecting intravenously

Answer

It has no muscle relaxant property

Answer

It is used as an intravenous induction agent

Question 4

Which inhalational anesthetic has the highest global warming potential?

Accepted Answer

Desflurane

Answer

Isoflurane

Answer

Sevoflurane

Answer

Halothane

Question 5

Which inhalational agent has the least MAC?

Accepted Answer

Halothane

Answer

Xenon

Answer

Sevoflurane

Answer

Isoflurane

Question 6

Dissociative anaesthesia is produced by?

Accepted Answer

Ketamine

Answer

Etomidate

Answer

Propofol

Answer

Thiopentone

Question 7

Which inhalational anesthetic agent is known to be hepatotoxic?

Accepted Answer

Halothane

Answer

Enflurane

Answer

Desflurane

Answer

Sevoflurane

Question 8

Which anaesthetic drug contributes to green house effect?

Accepted Answer

Desflurane

Answer

Enflurane

Answer

Sevoflurane

Answer

Halothane

Question 9

Intraocular pressure is increased by which anaesthetic?

Accepted Answer

Ketamine

Answer

Nitrous Oxide

Answer

Isoflurane

Answer

Propofol

Question 10

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

General Anesthesia — MCQs

General Anesthesia — MCQs

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