Neonatal Nurse Practitioner Practice Exam

In metabolic acidosis, how does the body typically compensate in terms of CO2 levels?

1. Increase CO2

2. Decrease CO2

3. No change in CO2

4. Increase HCO3 to balance CO2

The correct answer is: Decrease CO2

In metabolic acidosis, the body typically compensates by decreasing carbon dioxide (CO2) levels. This process occurs because the accumulation of acids in the body raises hydrogen ion concentration, resulting in a lower pH. To counteract this acidosis, the body employs respiratory compensation. When metabolic acidosis is present, the respiratory center in the brain senses the increased acidity and signals the lungs to increase the rate and depth of breathing. This hyperventilation leads to a greater exhalation of CO2, which reduces its concentration in the blood. Lower CO2 levels result in less carbonic acid formation, thereby helping to elevate the pH back toward normal. This adaptive mechanism reflects a key principle of acid-base physiology by illustrating how the respiratory system can promptly adjust to metabolic disturbances. The other options, such as increasing CO2 or maintaining CO2 levels, do not align with the body’s physiological response to metabolic acidosis, which aims to correct the acid-base imbalance through respiratory changes.