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 statements is NOT true regarding rapid induction of anesthesia?

Sellick's maneuver is always required.. ***Sellick's maneuver is always required.*** - **Sellick's maneuver**, or cricoid pressure, is applied to compress the esophagus against the vertebrae, aiming to prevent **gastric regurgitation** and aspiration during rapid sequence intubation (RSI). - While historically considered a standard component of RSI, its routine use has been increasingly questioned due to a lack of strong evidence supporting its efficacy and potential to impede glottic visualization and intubation. It is not "always" required; its application is often at the discretion of the anesthetist based on patient factors and risk assessment. *Pre-oxygenation is mandatory* - **Pre-oxygenation** is a critical step in rapid sequence induction, involving administering 100% oxygen for several minutes prior to induction. - This denitrogenates the functional residual capacity (FRC), creating an oxygen reservoir that extends the safe apnea time, thus preventing **hypoxemia** during the intubation attempt. *Suxamethonium is often used.* - **Suxamethonium** (succinylcholine) is a depolarizing neuromuscular blocker primarily used in rapid sequence intubation due to its **ultra-rapid onset** (30-60 seconds) and short duration of action (5-10 minutes). - Its rapid action facilitates quick muscle relaxation for tracheal intubation, which is crucial for minimizing the risk of aspiration in patients with a full stomach or other risk factors. *Mechanical ventilation is typically avoided before intubation.* - During rapid sequence induction, **positive pressure ventilation** with a bag-valve mask is typically avoided before intubation to prevent gastric insufflation. - Gastric insufflation can increase the risk of **regurgitation** and pulmonary aspiration of gastric contents, which is a major concern in patients undergoing RSI.

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: Which of the following anesthetic agents causes the LEAST severe complications when accidentally injected intra-arterially?

Propofol. **Propofol** * **Propofol** has a relatively low incidence and severity of complications if accidentally injected intra-arterially because of its **lipid emulsion formulation** and mild irritant properties compared to other agents. * While any intra-arterial injection can cause problems, the milder venoconstriction and less direct tissue damage make its intra-arterial complication profile less severe than alternative agents. *Thiopentone* * **Thiopentone** (Thiopental) is highly alkaline, and accidental intra-arterial injection can cause **intense pain**, **vasospasm**, and **gangrene** due to precipitation in the arterioles and widespread endothelial damage. * This severe complication arises from its extreme pH and crystal formation, leading to profound ischemia. *Midazolam* * Accidental intra-arterial injection of **Midazolam** can cause **pain**, **spasm**, and **local tissue damage** due to its relatively acidic pH and solvent properties, though generally less severe than thiopentone. * While not as catastrophic as thiopentone, it can still lead to significant discomfort and localized vascular issues. *Methohexitone* * **Methohexitone** is also an alkaline barbiturate derivative, similar in nature to thiopentone, and its intra-arterial injection carries a significant risk of **vasospasm**, **pain**, and potentially **tissue necrosis**. * Its strong irritant properties and ability to precipitate within the vasculature make it a dangerous agent for inadvertent intra-arterial administration.

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 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 anaesthetic agent has maximum MAC ?

Nitrous Oxide (N2O). ***Nitrous Oxide (N2O)*** - **Nitrous Oxide** has the highest **minimum alveolar concentration (MAC)** of all commonly used inhalational anesthetics, approximately 104%. - A high MAC indicates **low potency**, meaning that a large concentration is required to achieve anesthetic effects. *Ether* - **Ether** has a MAC of about 1.92%, which is significantly lower than that of Nitrous Oxide. - Its use has largely been replaced due to its flammability, slow induction, and recovery times. *Methoxyfluorane* - **Methoxyfluorane** is known for having a very low MAC, around 0.16%, making it the most potent inhalational anesthetic. - Due to its high potency and significant nephrotoxicity, its use is now very limited. *Halothane* - **Halothane** has a MAC of approximately 0.75%. - While it was a widely used inhalational anesthetic, it has largely been replaced due to concerns about **halothane hepatitis** and arrhythmogenicity.

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 statements is NOT true regarding rapid induction of anesthesia?

Accepted Answer

Sellick's maneuver is always required.

Answer

Suxamethonium is often used.

Answer

Mechanical ventilation is typically avoided before intubation.

Answer

Pre-oxygenation is mandatory

Question 3

Dissociative anaesthesia is produced by?

Accepted Answer

Ketamine

Answer

Etomidate

Answer

Propofol

Answer

Thiopentone

Question 4

Which inhalational agent has the least MAC?

Accepted Answer

Halothane

Answer

Xenon

Answer

Sevoflurane

Answer

Isoflurane

Question 5

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

Accepted Answer

N2O

Answer

Halothane

Answer

Enflurane

Answer

Desflurane

Question 6

Who coined the term "balanced anaesthesia"?

Accepted Answer

Lundy (John S. Lundy)

Answer

Simpson

Answer

Fischer

Answer

Morton

Question 7

Which of the following anesthetic agents causes the LEAST severe complications when accidentally injected intra-arterially?

Accepted Answer

Propofol

Answer

Thiopentone

Answer

Methohexitone

Answer

Midazolam

Question 8

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 9

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

Accepted Answer

Ketamine

Answer

Thiopental

Answer

Alfentanil

Answer

Propofol

Question 10

Which anaesthetic agent has maximum MAC ?

Accepted Answer

Nitrous Oxide (N2O)

Answer

Ether

Answer

Methoxyfluorane

Answer

Halothane

General Anesthesia — MCQs

General Anesthesia — MCQs

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