PAEA Surgery End Of Rotation (EOR) Practice Exam

What does decreased CO2 and increased pH signify?

1. Respiratory acidosis

2. Metabolic acidosis

3. Respiratory alkalosis

4. Metabolic alkalosis

The correct answer is: Respiratory alkalosis

Decreased CO2 and increased pH indicate a state of respiratory alkalosis. This condition occurs when there is excessive breathing (hyperventilation), which leads to the removal of carbon dioxide (CO2) from the bloodstream. As CO2 decreases, the levels of carbonic acid in the blood also decrease, resulting in a rise in blood pH (becoming more alkaline). In summary, the combination of decreased CO2 and increased pH translates to a more basic environment, characteristic of respiratory alkalosis, where the primary disturbance is respiratory rather than metabolic. In metabolic conditions, alterations in CO2 levels generally reflect compensatory mechanisms in response to changes in acid-base balance, but they don't directly lead to these symptoms. Therefore, while other conditions like metabolic acidosis or alkalosis involve changes in bicarbonate levels that affect pH, they do not align with the specific changes in CO2 and pH described in this scenario.