Neonatal Nurse Practitioner Practice Exam

Which clinical condition is characterized by a decrease in carbon dioxide?

1. Metabolic acidosis

2. Respiratory acidosis

3. Metabolic alkalosis

4. Respiratory alkalosis

The correct answer is: Respiratory alkalosis

The clinical condition characterized by a decrease in carbon dioxide is respiratory alkalosis. This occurs when there is an increase in the rate or depth of breathing (hyperventilation), leading to excessive loss of carbon dioxide from the body. Carbon dioxide is a product of metabolism and is normally present in the blood at a certain level; when levels drop significantly due to hyperventilation, it results in an increase in blood pH, making it more alkaline. In contrast, conditions like metabolic acidosis or respiratory acidosis involve either the accumulation of acids or the retention of carbon dioxide, respectively. Metabolic alkalosis is characterized by an increase in bicarbonate or loss of hydrogen ions, which does not involve a direct decrease in carbon dioxide but rather an increase in the blood's alkalinity due to other factors. Therefore, respiratory alkalosis is specifically linked to the reduction of carbon dioxide levels due to the body's respiratory response.