NEET-PG 2025 - Anesthesiology PYQs Practice Questions

Q: A patient undergoing surgery receives a muscle relaxant and soon develops flushing and rashes over the neck and anterior chest. Which of the following muscle relaxants is most commonly associated with this reaction?

Atracurium. ***Atracurium*** - The characteristic reaction described (flushing and rashes over the neck and chest) is often termed an **anaphylactoid reaction** due to **direct non-immunological histamine release** from mast cells. - Among the non-depolarizing muscle relaxants, **atracurium** and mivacurium are the most common causes of significant, dose-dependent histamine release, leading to cutaneous vasodilation (flushing) and potential hypotension. *Cisatracurium* - Although cisatracurium is an isomer of atracurium, it is associated with a **significantly lower incidence** of **histamine release** and provides better cardiovascular stability. - It is often favored over atracurium for patients with severe cardiovascular disease. *Vecuronium* - Vecuroniumbelongs to the **aminosteroid class** (e.g., rocuronium, vecuronium, pancuronium) of muscle relaxants, which are generally associated with **minimal-to-negligible risk** of **histamine release**. - It is preferred for its high degree of **cardiovascular stability** (minimal effect on heart rate or blood pressure). *Pancuronium* - Pancuronium, another **aminosteroid**, has a very low potential for histamine release, thus not typically causing flushing or rash. - Its main side effect is a **vagolytic action** (antimuscarinic effect) that often causes significant **tachycardia** and hypertension. [Practice more Anesthesiology PYQs on OnCourse]

Q: Patient in hospital was given IVF and patient develops hyperchloremic metabolic acidosis. Which fluid will cause this?

NS. ***NS*** - **Normal Saline (0.9% NaCl)** contains a **chloride concentration of 154 mEq/L**, which is unphysiologically high (supranormal) compared to plasma (approx. 100 mEq/L). - Rapid infusion leads to the retention of excess chloride and dilution of serum bicarbonate, resulting in a **non-anion gap (hyperchloremic) metabolic acidosis**. *RL* - Ringer's Lactate (RL) is a **buffered solution** because it contains **lactate (28 mEq/L)**, which is metabolized by the liver into bicarbonate. - Because of the bicarbonate precursor (lactate) and a near-physiologic chloride concentration (109 mEq/L), RL tends to **prevent or correct** acidosis, rather than causing it. *DNS* - Dextrose Normal Saline (DNS) still contains the **supranormal chloride concentration** (154 mEq/L) from the normal saline component, posing a similar theoretical risk. - However, it is typically less associated with severe acidosis than pure NS in large volumes, and often the primary differentiating fluid in this context is the **buffered RL**. *5 % dextrose* - **5% Dextrose in Water (D5W)** contains no electrolytes (salt) and is only used to provide free water and small amounts of calories. - Rapid infusion of D5W results in dilution and can cause **hyponatremia** and free water excess, but it cannot precipitate hyperchloremic acidosis. [Practice more Anesthesiology PYQs on OnCourse]

Q: A 35-year-old male undergoing abdominal surgery under general anesthesia develops sudden generalized muscle rigidity, rapid increase in body temperature, and tachycardia shortly after administration of sevoflurane and succinylcholine. His end-tidal CO2 is rising despite controlled ventilation. What is the most appropriate immediate treatment?

Dantrolene. ***Dantrolene*** - This clinical scenario is a classic presentation of **Malignant Hyperthermia (MH)**, a life-threatening pharmacogenetic disorder triggered by volatile anesthetics (like sevoflurane) and succinylcholine. - **Dantrolene sodium** is the only specific treatment for MH; it acts by directly interfering with excitation-contraction coupling in skeletal muscle, reducing the intracellular calcium release from the sarcoplasmic reticulum. *Diazepam* - Diazepam is an anxiolytic/sedative and an anticonvulsant; it might be used to control generalized seizures or anxiety, but it is **not effective** against the massive muscle contracture seen in Malignant Hyperthermia. - Administering diazepam would only treat minor symptoms or anxiety and delay the necessary specific treatment, leading to potentially fatal outcomes from **rhabdomyolysis and hyperkalemia**. *Pancuronium* - Pancuronium is a **non-depolarizing neuromuscular blocking agent** (muscle relaxant) and will not halt the underlying pathological process of Malignant Hyperthermia, which involves uncontrolled calcium release from the sarcoplasmic reticulum. - Although it causes paralysis, it would not address the **hypermetabolic state** (characterized by rising ETCO2 and temperature) that is the hallmark of MH. *Vecuronium* - Vecuronium is also a **non-depolarizing neuromuscular blocking agent** used for muscle relaxation during anesthesia, similar to pancuronium. - While it causes muscle paralysis, it does not correct the massive, uncontrolled increase in intracellular calcium that drives the **malignant hyperthermic crisis**. [Practice more Anesthesiology PYQs on OnCourse]

Question 1

A patient undergoing surgery receives a muscle relaxant and soon develops flushing and rashes over the neck and anterior chest. Which of the following muscle relaxants is most commonly associated with this reaction?

Accepted Answer

Atracurium

Answer

Vecuronium

Answer

Pancuronium

Answer

Cisatracurium

Question 2

Patient in hospital was given IVF and patient develops hyperchloremic metabolic acidosis. Which fluid will cause this?

Accepted Answer

NS

Answer

RL

Answer

5 % dextrose

Answer

DNS

Question 3

A 35-year-old male undergoing abdominal surgery under general anesthesia develops sudden generalized muscle rigidity, rapid increase in body temperature, and tachycardia shortly after administration of sevoflurane and succinylcholine. His end-tidal CO2 is rising despite controlled ventilation. What is the most appropriate immediate treatment?

Accepted Answer

Dantrolene

Answer

Vecuronium

Answer

Diazepam

Answer

Pancuronium

NEET-PG 2025 — Anesthesiology