NEET-PG 2013 - Anesthesiology Practice Questions

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: Which of the following is not a sign of stellate ganglion block?

Exophthalmos. ***Exophthalmos*** - A stellate ganglion block paralyses the **sympathetic nervous system** to the head and neck. - **Exophthalmos** (bulging of the eye) is a sign of sympathetic **hyperactivity**, not blockade. *Miosis* - **Miosis** (pupil constriction) is a classic sign of sympathetic blockade. - The **dilator pupillae muscle** is paralyzed, leading to unopposed parasympathetic action. *Nasal congestion* - **Nasal congestion** is a common sign due to the **vasodilation** of nasal blood vessels from sympathetic blockade. - Sympathetic nerves normally cause **vasoconstriction** in the nasal mucosa. *Conjunctival redness* - **Conjunctival redness** occurs due to **vasodilation** of conjunctival blood vessels, a direct effect of sympathetic blockade. - This is part of the **Horner's syndrome** presentation.

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: Drug of choice for Bier's block ?

Lidocaine. ***Lidocaine*** - **Lidocaine** is the preferred local anesthetic for **Bier's block** (intravenous regional anesthesia) due to its rapid onset and good safety profile. - Its relatively short duration of action and **minimal cardiotoxicity** upon systemic release are favorable for this technique. *Bupivacaine* - **Bupivacaine** has a **longer duration of action** and is associated with a higher risk of **cardiotoxicity** when inadvertently delivered systemically, making it less suitable for Bier's block. - Its use in Bier's block is generally avoided due to the potential for significant adverse events if the tourniquet malfunctions or is released prematurely. *Etidocaine* - **Etidocaine** is a potent, **long-acting local anesthetic** with a similar toxicity profile to bupivacaine, making it less ideal for Bier's block. - Its prolonged action and higher potential for systemic toxicity make it less favorable for a procedure where rapid washout and lower systemic risk are desired. *Ropivacaine* - **Ropivacaine** is an amide-type local anesthetic with a similar efficacy to bupivacaine but with a **lower potential for cardiotoxicity**. - While safer than bupivacaine, **lidocaine** is still generally preferred for Bier's block due to its established safety record, faster onset, and lower cost.

Q: What is the definition of conscious sedation?

Sedation with ability to respond to verbal commands. ***Sedation with ability to respond to verbal commands*** - Conscious sedation involves a drug-induced depression of consciousness during which the patient **retains the ability to respond purposefully to verbal commands**. - This level of sedation ensures that the patient's **airway reflexes** and **ventilatory function** remain intact. *CNS depression with unconsciousness* - This describes **general anesthesia** or **deep sedation**, where the patient is unable to respond purposefully to verbal commands. - In such states, spontaneous ventilation may be **inadequate**, and **airway support** is often required. *Sedation with inability to respond to verbal commands* - This definition aligns with **deep sedation** or **general anesthesia**, where the patient's consciousness is significantly depressed. - At this level, patients may require assistance in maintaining a **patent airway** and adequate ventilation. *None of the options* - This option is incorrect because one of the provided definitions accurately describes conscious sedation. - The definition of conscious sedation is well-established in clinical practice, emphasizing the **preservation of responsiveness**.

Q: Circuit of choice for controlled ventilation ?

Type D. **Type D** - The **Type D circuit** (also known as the **Bain circuit** or a modified Mapleson D circuit) is highly efficient for **controlled ventilation** due to its fresh gas flow entering near the patient, effectively sweeping away exhaled gases. - Its design maintains a relatively constant **expiratory resistance**, making it suitable for precise control of ventilation parameters. *Magill circuit* - The **Magill circuit** (Mapleson A) is efficient for **spontaneous ventilation** but requires a high fresh gas flow to prevent rebreathing during controlled ventilation. - During controlled ventilation, a high minute volume is required to flush out expired gases efficiently, which can be wasteful of anesthetic agents. *Type C* - The **Type C circuit** (Mapleson C circuit) is a simple system useful for **resuscitation** and short procedures but is inefficient for prolonged controlled ventilation. - It has a high resistance to gas flow and a tendency for significant rebreathing during both spontaneous and controlled breathing, leading to high CO2 levels. *Type E* - The **Type E circuit** (Mapleson E circuit) is a basic T-piece system, primarily used for **spontaneous breathing in infants and children**. - It lacks a reservoir bag and adjustable pressure limiting valve, making it unsuitable for controlling ventilation effectively in adults.

Q: Inhalational agent of choice for neurosurgery?

Isoflurane. ***Isoflurane*** - **Isoflurane** is preferred in neurosurgery due to its minimal impact on **cerebral blood flow** and **intracranial pressure (ICP)**, allowing cerebral autoregulation to be largely preserved. - It maintains **cerebral perfusion pressure** well and has a relatively fast onset and offset, facilitating neurological assessment post-operatively. *Halothane* - **Halothane** significantly increases **cerebral blood flow** and **intracranial pressure (ICP)**, which is undesirable in neurosurgical patients. - Its slow elimination can prolong recovery and neurological assessment, making it unsuitable for neurosurgery. *Enflurane* - **Enflurane** can cause central nervous system excitation and has been associated with **seizure activity** at higher concentrations, making it contraindicated in neurosurgical procedures. - Like halothane, it can also increase **cerebral blood flow** and **intracranial pressure**. *N2O* - **Nitrous oxide (N2O)** should be avoided in neurosurgery, especially if there's a risk of **intracranial air** or **pneumocephalus**, as it can expand air-filled spaces and increase ICP. - It also has a weak anesthetic effect and is often combined with other agents, but its cerebral vasodilatory properties can still be problematic.

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: 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: 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.

Question 1

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

Accepted Answer

N2O

Answer

Halothane

Answer

Enflurane

Answer

Desflurane

Question 2

Which of the following is not a sign of stellate ganglion block?

Accepted Answer

Exophthalmos

Answer

Miosis

Answer

Conjunctival redness

Answer

Nasal congestion

Question 3

Which anesthetic agent is known for providing smooth induction?

Accepted Answer

Isoflurane

Answer

Halothane

Answer

Enflurane

Answer

Sevoflurane

Question 4

Drug of choice for Bier's block ?

Accepted Answer

Lidocaine

Answer

Bupivacaine

Answer

Etidocaine

Answer

Ropivacaine

Question 5

What is the definition of conscious sedation?

Accepted Answer

Sedation with ability to respond to verbal commands

Answer

CNS depression with unconsciousness

Answer

Sedation with inability to respond to verbal commands

Answer

None of the options

Question 6

Circuit of choice for controlled ventilation ?

Accepted Answer

Type D

Answer

Magill circuit

Answer

Type C

Answer

Type E

Question 7

Inhalational agent of choice for neurosurgery?

Accepted Answer

Isoflurane

Answer

Halothane

Answer

Enflurane

Answer

N2O

Question 8

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 9

Which anaesthetic drug contributes to green house effect?

Accepted Answer

Desflurane

Answer

Enflurane

Answer

Sevoflurane

Answer

Halothane

Question 10

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

NEET-PG 2013 — Anesthesiology