A 74-year-old woman with a history of a previous total abdominal hysterectomy presents with abdominal pain and distention for 3 days. She is noted on plain films to have dilated small-bowel and air-fluid levels. She is taken to the operating room for a small-bowel obstruction. Which of the following inhalational anesthetics should be avoided because of accumulation in air-filled cavities during general anesthesia?

## Core Concept
The question tests the understanding of the properties of inhalational anesthetics, specifically their behavior in air-filled cavities during general anesthesia. The key concept here is the potential for certain anesthetics to diffuse into and accumulate in air-filled spaces, which can lead to expansion of these spaces and potentially compromise the surgical site or the patient's hemodynamics.

## Why the Correct Answer is Right
The correct answer, **Desflurane**, is a potent inhalational anesthetic known for its low solubility in blood and tissues. However, its low solubility also means it can rapidly diffuse into air-filled cavities. In the context of a patient with a small-bowel obstruction, the use of desflurane could lead to significant expansion of the bowel lumen due to diffusion of the anesthetic into the bowel, potentially complicating the surgical procedure.

## Why Each Wrong Option is Incorrect
- **Option A: Isoflurane** has a moderate solubility in blood and tissues. While it does diffuse into air-filled spaces, its moderate solubility compared to desflurane makes it less likely to cause significant accumulation and expansion.
- **Option B: Sevoflurane** also has a moderate solubility in blood. It is less likely than desflurane to accumulate in air-filled cavities to a clinically significant extent.
- **Option D: Halothane** has a higher solubility in blood and tissues compared to desflurane, isoflurane, and sevoflurane. This higher solubility means it is less likely to rapidly accumulate in air-filled cavities.

## Clinical Pearl / High-Yield Fact
A key point to remember is that anesthetics with low blood solubility, like **desflurane**, can accumulate in air-filled spaces, potentially causing them to expand. This is particularly relevant in cases of bowel obstruction, where such expansion could interfere with surgical exposure or patient management.

## Correct Answer Line
**Correct Answer: C. Desflurane**

✓ Correct Answer: B. Nitrous oxide