## **Core Concept**
The patient's blood gas values indicate an acid-base imbalance. The given values are: PO2 = 85 mmHg, PCO2 = 50 mmHg, pH = 7.2, and HCO3- = 32 meq/l. This scenario suggests a respiratory acidosis with a compensatory increase in bicarbonate.

## **Why the Correct Answer is Right**
The patient's pH is 7.2, which is acidic. The PCO2 is elevated at 50 mmHg, indicating a respiratory component to the acidosis. The HCO3- level is also elevated at 32 meq/l, suggesting a compensatory response to the acidosis, likely through renal retention of bicarbonate. This pattern is consistent with **chronic respiratory acidosis**, where the body compensates for the respiratory acidosis by increasing bicarbonate reabsorption in the kidneys.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is not provided, but typically, it would represent a different diagnosis.
- **Option B:** This option is not provided, but if it suggested a different acid-base disorder not consistent with the given lab values, it would be incorrect based on the lab values provided.
- **Option C:** This option is not provided, but if it suggested a primary metabolic disorder without acknowledging the respiratory component, it would be incorrect.
- **Option D:** This option is not provided, but if it did not accurately reflect a condition associated with chronic respiratory acidosis and compensatory metabolic alkalosis (or increase in bicarbonate), it would be incorrect.

## **Clinical Pearl / High-Yield Fact**
In chronic respiratory acidosis, the body compensates by increasing bicarbonate levels. A useful mnemonic to remember the compensation is: for every 10 mmHg increase in PCO2, HCO3- increases by 1 meq/l in acute settings, but in chronic settings, the increase is about 3.5 meq/l for every 10 mmHg increase in PCO2. This patient's scenario suggests a chronic process given the significant elevation in bicarbonate.

## **Correct Answer:** C. Chronic respiratory acidosis.