NEET-PG 2022 — Anesthesiology

Q: Identify the mask used for patients requiring high concentrations of oxygen.

Non-rebreathing mask. ***Non-rebreathing mask*** - The **non-rebreathing mask** delivers the **highest concentration of oxygen** (FiO2 60-90%) among standard oxygen masks due to a one-way valve that prevents exhaled air from returning to the reservoir bag and ensures only pure oxygen is inhaled. - It is identifiable by the **reservoir bag** which fills with oxygen and one-way valves. *Hudson mask* - The **Hudson mask**, also known as a simple face mask, delivers a **moderate concentration of oxygen (FiO2 35-50%)** and does not have the reservoir bag or one-way valves seen in the image. - It is used for patients requiring a higher oxygen concentration than nasal cannulae, but less than a non-rebreather. *Nebulizer* - A **nebulizer** is a device used to administer medication in the form of a **mist**, typically for respiratory conditions, not primarily for administering high concentrations of oxygen. - While it can be oxygen-driven, its primary function is drug delivery, not oxygen concentration. *Venturi mask* - The **Venturi mask** delivers **precise and consistent concentrations of oxygen (FiO2 24-60%)** through interchangeable jets, which are not visible in the depicted mask. - It is used when precise control over oxygen delivery is crucial, such as in patients with **COPD**. [Practice more Anesthesiology PYQs on OnCourse]

Q: The image given below shows neuromuscular monitoring of the patient after anesthesia. What is the most commonly used nerve for monitoring?

Ulnar nerve. ***Ulnar nerve*** - The **ulnar nerve** is the most commonly chosen site for neuromuscular monitoring due to its ease of accessibility and predictable response of the **adductor pollicis muscle**. - Stimulation of the ulnar nerve at the wrist causes **adduction of the thumb**, which is easily quantifiable and provides reliable information about neuromuscular blockade. *Median nerve* - While the median nerve can be monitored, it is **less commonly used** than the ulnar nerve due to potential for confusing responses or less clear twitch measurements. - Stimulation of the median nerve primarily leads to **flexion of the thumb and fingers**, but the adductor pollicis response from ulnar nerve stimulation is often preferred for its clear isolation. *Radial nerve* - The radial nerve innervates muscles involved in **wrist and finger extension**, which are not typically targeted for standard neuromuscular monitoring. - Its stimulation can be more complex to interpret and may not provide the precise information needed for monitoring paralytic depth in the same way as the ulnar nerve. *Metacarpal nerve* - The term "metacarpal nerve" is broad and refers to nerves near the metacarpals, which are **not primary sites** for direct neuromuscular blocking agent monitoring. - Specific named peripheral nerves like the ulnar, median, or radial nerves are targeted for their predictable muscle responses, not generalized metacarpal innervation. [Practice more Anesthesiology PYQs on OnCourse]

2 Previous Year Questions with Answers & Explanations

Questions

Identify the mask used for patients requiring high concentrations of oxygen.

The image given below shows neuromuscular monitoring of the patient after anesthesia. What is the most commonly used nerve for monitoring?