【正确答案】
A
【答案解析】Respiratory acidosis is associated with hypoventilation, which in this client suggests intake of a drug that suppresses the brain's respiratory center. Therefore, the nurse should assume the client has respiratory depression and should prepare to assist with ventilation. After the client's respiratory function has been stabilized, the nurse can safely monitor the heart rhythm, prepare for gastric lavage, and obtain a urine sample for drug screening.