NEET-PG 2017 Practice Questions

Q: Which finding indicates correct placement of needle in this nerve block? (Recent NEET Pattern 2016-17)

Increase in skin temperature of ipsilateral arm. ***Increase in skin temperature of ipsilateral arm*** - A successful **stellate ganglion block** interrupts the **sympathetic efferent fibers** that innervate the ipsilateral arm. - This interruption leads to **vasodilation** in the blood vessels of the arm, resulting in increased blood flow and thus, a rise in skin temperature. *Decrease in skin temperature of ipsilateral arm* - A decrease in skin temperature would indicate **vasoconstriction**, which is the opposite effect of a successful sympathetic block. - This would suggest either an ineffective block or stimulation of sympathetic activity. *Increase in sweating of ipsilateral arm* - The stellate ganglion also carries **sympathetic fibers** to the sweat glands. A successful block would inhibit sweat gland activity. - Increased sweating (known as **diaphoresis**) would indicate an inadequate block or irritation of the ganglion, leading to increased sympathetic outflow. *Decrease in sweating of ipsilateral arm* - While a **decrease in sweating** (anhidrosis) is indeed a sign of effective sympathetic blockade to the arm, it is typically less immediate and less clinically observable than the change in skin temperature. - The most easily and consistently observed sign of sympathetic denervation in the arm is the increase in skin temperature due to vasodilation.

Q: Which is correct about the anesthetic drugs X and Y in the image shown? (Recent NEET Pattern 2016-17)

Drug X is more fast acting than Y. ***Drug X is more fast acting than Y*** - The **oil:gas partition coefficient** for Drug X is lower than for Drug Y. A lower oil:gas partition coefficient typically correlates with a **faster onset of action** for inhaled anesthetics as it indicates lower solubility in blood and tissues, allowing for quicker equilibration in the brain. - While MAC is plotted against oil:gas partition coefficient, the question specifically asks about **onset of action**, which is primarily influenced by blood-gas solubility rather than oil-gas solubility. However, an anesthetic with lower oil-gas solubility (like X) would generally also have lower blood-gas solubility, leading to faster onset. *Drug Y is more fast acting than X* - Drug Y has a **higher oil:gas partition coefficient** compared to Drug X, indicating greater lipid solubility. - A higher oil:gas partition coefficient generally correlates with a **slower onset of action** for inhaled anesthetics, as more drug dissolves in lipids before reaching the brain. *Drug X and Y have equally fast onset of action* - The graph clearly shows that Drug X and Drug Y have different **oil:gas partition coefficients**. - Since the partition coefficients are different, their **solubility characteristics** and therefore their clinical onset of action would also be different. *Drug X and Y have equally fast onset of action but potency of X is more than Y* - Onset of action is **not equal** for X and Y due to their differing oil:gas partition coefficients. - Potency, represented by **MAC** (Minimum Alveolar Concentration), is inversely related to the oil:gas partition coefficient for many inhaled anesthetics. From the graph, Drug X has a higher MAC value than Drug Y (meaning it is **less potent** but acts faster).

Q: The application of the following product can lead to development of: (Recent NEET Pattern 2016-17)

Methemoglobinemia. ***Methemoglobinemia (Correct)*** - EMLA cream contains **lidocaine** and **prilocaine**, both of which are **amide-type local anesthetics** - Prilocaine, in particular, can cause methemoglobinemia due to its metabolite, **o-toluidine**, which oxidizes hemoglobin to methemoglobin - While methemoglobinemia is rare with proper use, it is a known and serious adverse effect, especially when applied to large areas, on broken skin, or in infants - This is the most specific adverse effect associated with prilocaine in EMLA cream *Seizures (Incorrect)* - Seizures are a known systemic toxicity of local anesthetics like lidocaine and prilocaine but are usually associated with **very high systemic concentrations**, often from accidental intravenous injection or excessive application over large areas - While possible with overdose, methemoglobinemia is a more specific and direct concern linked to prilocaine's metabolic pathway - CNS toxicity typically requires systemic absorption beyond what occurs with proper topical use *Depression (Incorrect)* - Depression is **not a direct or common adverse effect** of EMLA cream or its components - Systemic absorption of local anesthetics can cause central nervous system effects, but depression is generally not among them - CNS effects more commonly involve excitation (restlessness, tremors) or sedation depending on the dose *Hypertension (Incorrect)* - Local anesthetics generally cause **vasodilation** at therapeutic doses, potentially leading to **hypotension** rather than hypertension, especially with systemic absorption - Hypertension is not a characteristic side effect associated with the topical application of EMLA cream - The cardiovascular effects of local anesthetics, when present, typically involve decreased blood pressure and myocardial depression

Question 1

Which finding indicates correct placement of needle in this nerve block? (Recent NEET Pattern 2016-17)

Accepted Answer

Increase in skin temperature of ipsilateral arm

Answer

Decrease in skin temperature of ipsilateral arm

Answer

Increase in sweating of ipsilateral arm

Answer

Decrease in sweating of ipsilateral arm

Question 2

Which is correct about the anesthetic drugs X and Y in the image shown? (Recent NEET Pattern 2016-17)

Accepted Answer

Drug X is more fast acting than Y

Answer

Drug X and Y have equally fast onset of action

Answer

Drug X and Y have equally fast onset of action but potency of X is more than Y

Answer

Drug Y is more fast acting than X

Question 3

The application of the following product can lead to development of: (Recent NEET Pattern 2016-17)

Accepted Answer

Methemoglobinemia

Answer

Seizures

Answer

Depression

Answer

Hypertension

NEET-PG 2017

Anesthesiology

Pharmacology