NCC Certified Electronic Fetal Monitoring (C-EFM) Practice Exam

What acid-base status is indicated by a pH of 6.98, PCO2 of 49, HCO3 of 16, and BE of -16?

1. Respiratory acidosis

2. Metabolic acidosis

3. Mixed acidosis

4. Respiratory alkalosis

The correct answer is: Metabolic acidosis

The acid-base status indicated by the given values (pH of 6.98, PCO2 of 49 mmHg, HCO3 of 16 mEq/L, and BE of -16) points to metabolic acidosis. In this situation, the pH of 6.98 falls below the normal range of 7.35-7.45, indicating acidosis. The HCO3 level of 16 mEq/L is significantly lower than the normal range of 22-28 mEq/L, which supports the diagnosis of metabolic acidosis because it reflects a primary decrease in bicarbonate. While the PCO2 of 49 mmHg is elevated, which could indicate respiratory compensation, it is important to note that the primary issue here is a low bicarbonate level. This means the lungs may not be effectively compensating for the metabolic acidosis yet, hence the pH remains low. The base excess (BE) of -16 further confirms that there is a significant deficit in bicarbonate, reinforcing that this is predominantly a metabolic process rather than a respiratory one. The other options are inconsistent with the presented data as they either suggest elevated pH (alkalosis options) or do not align with the