单选题
A client hospitalized with a pneumothorax has the following arterial blood gas (ABG) analysis: pH, 7.19; partial pressure of arterial carbon dioxide (PaCO2), 63 mmHg; and 
, 22 mEq/L. A chest tube was inserted and oxygen administered at 4 L/min by nasal cannula. One hour after the initiation of treatment, ABG analysis reveals: pH, 7.28; PaCO2, 52 mmHg; and 
, 22 mEq/L. A chest tube was inserted and oxygen administered at 4 L/min by nasal cannula. One hour after the initiation of treatment, ABG analysis reveals: pH, 7.28; PaCO2, 52 mmHg; and
【正确答案】
D
【答案解析】The original ABG analysis reveals respiratory acidosis commonly seen with a pneumothorax. After chest tube insertion, the client's respiratory status has improved, pH is increasing toward normal, and the PaCO2 is decreasing. ABG analysis in respiratory alkalosis shows an elevated pH and a low PaCO2. Assessment findings are more important than ABG analysis in determining whether the client requires intubation or if respiratory arrest is imminent.