单选题 For the child experiencing excessive vomiting secondary to pyloric stenosis, the nurse should assess the child for which of the following acid-base imbalances?
A. Respiratory alkalosis.
B. Respiratory acidosis.
C. Metabolic alkalosis.
D. Metabolic acidosis.

【正确答案】 C

【答案解析】Metabolic alkalosis occurs because of the excessive loss of potassium, hydrogen, and chloride in the vomitus. Chloride loss leads to a compensatory increase in the number of bicarbonate ions. The bicarbonate side of the carbonic acid-base bicarbonate is increased, and the pH becomes more alkaline.