**Core Concept**
The management of severe bronchiolitis in children involves careful monitoring of respiratory status, including PaCO2 levels. The primary goal is to maintain a stable pH level, often achieved through the administration of bicarbonate in cases of significant acidosis. The relationship between PCO2 and bicarbonate administration is crucial in pediatric critical care.

**Why the Correct Answer is Right**
For every 10 mm Hg increase in PaCO2, approximately 1 mEq of bicarbonate is recommended to be administered. This is based on the principle of maintaining a stable acid-base balance. The increase in PaCO2 leads to a decrease in pH, and bicarbonate administration helps to counteract this effect. The recommended dose of 1 mEq of bicarbonate for every 10 mm Hg increase in PaCO2 is a general guideline in pediatric critical care.

**Why Each Wrong Option is Incorrect**
**Option A:** Administering 2 mEq of bicarbonate for every 10 mm Hg increase in PaCO2 would lead to excessive bicarbonate administration, potentially causing metabolic alkalosis.

**Option B:** Increasing bicarbonate by 4 mEq for every 10 mm Hg increase in PaCO2 would be even more excessive and could lead to severe metabolic alkalosis, potentially causing complications such as seizures.

**Option C:** The option of administering 8 mEq of bicarbonate for every 10 mm Hg increase in PaCO2 is not supported by current pediatric critical care guidelines and would likely cause significant metabolic alkalosis.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that bicarbonate administration should be used judiciously in pediatric critical care, and its use should be guided by the principles of acid-base balance and careful monitoring of pH levels.

**✓ Correct Answer: D. 1. For every 10 mm Hg increase in PaCO2, approximately 1 mEq of bicarbonate is recommended to be administered.**