Anaesthetic agent of choice in congenital heart disease with right to left shunt is
**Core Concept**
In patients with congenital heart disease and a right-to-left shunt, the anaesthetic agent of choice must be carefully selected to prevent the shunting of deoxygenated blood from the right side of the heart to the left side, which can lead to hypoxia. This scenario requires an anaesthetic agent that is highly soluble in blood and does not readily cross the alveolar-capillary membrane.
**Why the Correct Answer is Right**
The anaesthetic agent of choice in this scenario is sevoflurane, which is highly soluble in blood and has a low blood/gas partition coefficient. This allows it to be taken up and eliminated slowly, reducing the risk of sudden changes in blood flow and oxygenation. Additionally, sevoflurane has a low pungency, making it suitable for inhalational induction in patients with congenital heart disease.
**Why Each Wrong Option is Incorrect**
* **Option A:** Isoflurane is not the best choice in this scenario because it has a higher blood/gas partition coefficient than sevoflurane, which can lead to rapid changes in blood flow and oxygenation.
* **Option B:** Desflurane is not suitable due to its high pungency, which can cause airway irritation and increase the risk of laryngospasm in patients with congenital heart disease.
* **Option C:** Halothane is not the best choice because it has a higher risk of cardiotoxicity and myocardial depression, which can be problematic in patients with congenital heart disease.
**Clinical Pearl / High-Yield Fact**
In patients with congenital heart disease and a right-to-left shunt, the anaesthetic agent of choice should have a high blood solubility and a low pungency to minimize the risk of hypoxia and airway irritation.
**Correct Answer:** C. Halothane.