Which of the following statements is NOT true regarding rapid induction of anesthesia?
Which drug is commonly used for emergency intubation?
Who coined the term "balanced anaesthesia"?
Which of the following anesthetics is known to increase intraocular pressure?
Which of the following statements about Nitrous Oxide (N2O) is true?
What is the PRIMARY application of capnography during patient monitoring?
Which of the following is a characteristic of the Supreme Laryngeal Mask Airway (LMA)?
Critical temperature of oxygen is?
Which anaesthetic belongs to the ester group?
Which inhalational agent has the least MAC?
NEET-PG 2013 - Anesthesiology NEET-PG Practice Questions and MCQs
Question 11: Which of the following statements is NOT true regarding rapid induction of anesthesia?
- A. Suxamethonium is often used.
- B. Mechanical ventilation is typically avoided before intubation.
- C. Pre-oxygenation is mandatory
- D. Sellick's maneuver is always required. (Correct Answer)
Explanation: ***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.
Question 12: Which drug is commonly used for emergency intubation?
- A. None of the options
- B. Etomidate (Correct Answer)
- C. Propofol
- D. Ketamine
Explanation: ***Etomidate*** - Etomidate is a **short-acting nonbenzodiazepine hypnotic** often preferred for rapid sequence intubation (RSI) due to its minimal impact on **hemodynamic stability**. - It induces **rapid unconsciousness** with a quick onset and offset, making it suitable for emergency airway management in patients who are hemodynamically compromised. *Propofol* - Propofol is a **potent intravenous anesthetic** that can cause significant **hypotension** due to vasodilation and myocardial depression. - While it provides rapid onset of sedation and amnesia, its cardiovascular side effects make it less ideal for patients with **unstable hemodynamics** during emergency intubation. *Ketamine* - Ketamine is a **dissociative anesthetic** that causes a cataleptic state, amnesia, and analgesia, often leading to **bronchodilation** and cardiovascular stimulation. - While useful in patients with **reactive airway disease** or hypotension, it can increase intracranial pressure and may induce sympathetic stimulation, which might not be ideal for all emergency intubation scenarios. *None of the options* - This option is incorrect because **Etomidate is a commonly used drug** for emergency intubation, particularly where hemodynamic stability is a concern. - Other agents are also used but Etomidate is a clear clinical choice in many situations.
Question 13: Who coined the term "balanced anaesthesia"?
- A. Simpson
- B. Fischer
- C. Morton
- D. Lundy (John S. Lundy) (Correct Answer)
Explanation: ***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."
Question 14: Which of the following anesthetics is known to increase intraocular pressure?
- A. Thiopental
- B. Alfentanil
- C. Ketamine (Correct Answer)
- D. Propofol
Explanation: ***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.
Question 15: Which of the following statements about Nitrous Oxide (N2O) is true?
- A. Least potent inhalational anesthetic (Correct Answer)
- B. Lighter than air
- C. Effective muscle relaxant
- D. Does not cause diffusion hypoxia
Explanation: **Least potent inhalational anesthetic** - Nitrous oxide has a **high Minimum Alveolar Concentration (MAC)** of approximately 104%, making it the least potent of the commonly used inhalational anesthetics. - Its high MAC means a very high concentration is required to achieve surgical anesthesia, which is why it is typically used as an adjunct to more potent agents. *Lighter than air* - The molecular weight of nitrous oxide (N2O) is 44, which is **heavier than air** (average molecular weight approximately 29 g/mol). - Its density is greater than air, meaning it would tend to sink rather than rise. *Effective muscle relaxant* - Nitrous oxide provides **minimal to no skeletal muscle relaxation** benefits. - If muscle relaxation is required, a neuromuscular blocking agent must be administered separately. *Does not cause diffusion hypoxia* - Nitrous oxide rapidly diffuses out of the blood into the alveoli during emergence, diluting the oxygen and carbon dioxide there. - This rapid diffusion can lead to **diffusion hypoxia** (also known as the "second gas effect"), necessitating the administration of 100% oxygen during recovery to prevent this complication.
Question 16: What is the PRIMARY application of capnography during patient monitoring?
- A. Correct intubation (Correct Answer)
- B. Pulmonary embolism
- C. Adequate ventilation
- D. Significant metabolic change
Explanation: ***Correct intubation*** - Capnography is the **gold standard** for confirming **endotracheal tube (ETT) placement** by detecting carbon dioxide in exhaled breath. - A persistent waveform indicates the ETT is in the **trachea**, while absence suggests esophageal intubation. *Pulmonary embolism* - While capnography can show a **decrease in end-tidal CO2 (ETCO2)** due to increased dead space in pulmonary embolism, it is not its primary or most definitive diagnostic application. - Other diagnostic methods like CT pulmonary angiogram are preferred for confirming pulmonary embolism. *Adequate ventilation* - Capnography provides information about **ETCO2 levels**, which can indirectly reflect adequate ventilation by showing CO2 elimination. - However, it's more direct application is intubation confirmation, and other measures like **tidal volume** and **respiratory rate** are also crucial for assessing overall ventilation. *Significant metabolic change* - Capnography can show changes in CO2 production reflecting metabolic rate, such as in **hypermetabolic states** (e.g., fever, sepsis) or hypometabolic states. - While useful for monitoring trends, its primary role is not for diagnosing such changes but rather intubation confirmation.
Question 17: Which of the following is a characteristic of the Supreme Laryngeal Mask Airway (LMA)?
- A. Designed specifically for infants
- B. Utilizes high pressure, low volume cuff design
- C. Includes a built-in drain tube (Correct Answer)
- D. Does not have a bite block
Explanation: ***Includes a built-in drain tube*** - The **Supreme Laryngeal Mask Airway (LMA)** features an integrated **drain tube** to facilitate gastric decompression and reduce the risk of aspiration. - This design allows for the passage of a gastric tube, which can be useful during longer procedures or in patients with a higher risk of gastric content regurgitation. *Designed specifically for infants* - While LMAs are available in various sizes for all age groups, the **Supreme LMA** is not designed *specifically* for infants; it is a general-purpose LMA available in multiple sizes for different patient populations. - Other LMA types, such as the LMA Unique, are more commonly associated with a broader pediatric application. *Utilizes high pressure, low volume cuff design* - The **Supreme LMA** actually utilizes a **low pressure, high volume cuff** design, which helps contour to the perilaryngeal anatomy and minimizes pressure on mucosal tissues. - A high pressure, low volume cuff is associated with traditional endotracheal tubes and could lead to increased tissue ischemia if used with an LMA. *Does not have a bite block* - The **Supreme LMA** incorporates an **integrated bite block** within its design to prevent occlusion of the airway tube from patient biting. - This feature helps maintain airway patency and protects the LMA from damage, making it a key characteristic.
Question 18: Critical temperature of oxygen is?
- A. -118°C (Correct Answer)
- B. 400°C
- C. 20°C
- D. 36.5°C
Explanation: ***-118°C*** - The **critical temperature** is the temperature above which a gas cannot be liquefied, no matter how much pressure is applied. - For oxygen, its critical temperature is approximately **-118°C**, meaning it can only exist as a gas above this temperature, regardless of pressure. *400°C* - This temperature is significantly **above** the critical temperature of oxygen, so oxygen would always be a gas at this temperature. - It does not represent any specific physical property of oxygen in relation to its phase changes. *20°C* - This temperature is also well **above** oxygen's critical temperature, so oxygen would remain in its gaseous state. - This is approximately room temperature, where oxygen is commonly found as a gas. *36.5°C* - This is close to typical human body temperature and is far **above** the critical temperature of oxygen. - At this temperature, oxygen exists only as a gas.
Question 19: Which anaesthetic belongs to the ester group?
- A. Lignocaine
- B. Propofol
- C. Procaine (Correct Answer)
- D. Benzocaine
Explanation: ***Procaine*** - **Procaine** is a classical **ester-type** local anesthetic, characterized by an ester linkage between the aromatic and amine parts of its chemical structure. - Ester-type local anesthetics are metabolized by **plasma pseudocholinesterase**, leading to a shorter duration of action compared to amides. *Benzocaine* - **Benzocaine** is also an ester local anesthetic, but it is typically used topically due to its poor water solubility and absorption. - While an ester, the question implies a common injectable agent, making procaine a more representative answer for the "ester group" in general anesthetic use. *Lignocaine* - **Lignocaine** (also known as lidocaine) is an **amide-type** local anesthetic, which can be identified by an amide linkage in its chemical structure. - Amide local anesthetics are primarily metabolized in the **liver** and generally have a longer duration of action than esters. *Propofol* - **Propofol** is a **short-acting intravenous general anesthetic** and is not classified as a local anesthetic or belonging to the ester group. - It works by potentiation of **GABA-A receptors** and is used for induction and maintenance of general anesthesia.
Question 20: Which inhalational agent has the least MAC?
- A. Halothane (Correct Answer)
- B. Xenon
- C. Sevoflurane
- D. Isoflurane
Explanation: ***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.