Which of the following ABG results would you most likely see for a patient who is having a mild asthma attack?

To get this one right, you have to be familiar with the typical ABG results that you would see for a patient with asthma.

For a mild asthma attack, you would expect the results to show respiratory alkalosis with hypoxemia. That is because, for a mild attack, it’s normal for the patient to be hyperventilating due to the shortness of breath. Now we just have to go through the answer choices to find the set of results for this interpretation.

We can automatically rule out A because the pH is decreased, which means acidosis is present. B and C both show alkalosis, however, in both cases the PaCO2 is elevated which means that it’s a metabolic issue—not respiratory alkalosis. So we can rule out those two as well.

For option D, the pH is increased and the PaCO2 is decreased, which shows respiratory alkalosis. Also note that the PaO2 is decreased, which indicates that hypoxemia is present. That means that we now know that the correct answer has to be D.

The correct answer is: D. pH = 7.47 PCO2 = 30 torr PaO2 = 62 torr