The nurse is caring for a patient with gastroenteritis who has been vomiting for 48 hours. A ...

B
The patient's history suggests metabolic alkalosis (due to loss of acid in the stomach resulting from vomiting) so the patient is likely to have decreased respiratory rate and depth as a means of retaining carbon dioxide and decreasing his pH. Because the patient has metabolic alkalosis, his breathing is more likely to be slow and shallow, so both statements beginning with He is breathing fast and deep to affect his pH are incorrect. In metabolic alkalosis, the pH is too high; trying to increasing the pH by breathing slow and shallow would not be desirable, even if it were possible.