護理師正在處理一位急性呼吸窘迫症候群（ARDS）的病人。哪項發現表明病人的病情正在惡化？
A nurse is managing a client with acute respiratory distress syndrome (ARDS). Which finding suggests the client's condition is worsening?
- ADecreased respiratory rate from 30 to 24 breaths per minute呼吸頻率從每分鐘 30 次降至 24 次
- BImproved oxygen saturation (SpO2) from 85% to 90% on the same ventilator settings相同呼吸器設定下，血氧飽和度 (SpO2) 從 85% 改善至 90%
- CReduced pulmonary edema as evidenced by decreased crackles囉音減少顯示肺水腫減輕
- DIncreased arterial-alveolar oxygen gradient (AaDO2)✓ 正解動脈-肺泡氧氣梯度 (AaDO2) 增加
ARDS 的特徵是肺泡-動脈氧分壓梯度（AaDO2）顯著擴大，代表氣體交換嚴重障礙。若 AaDO2 增加，表示儘管給予氧氣，動脈血氧仍難以提升，表示肺部損傷加劇，氣體交換功能惡化。選項 B、A、C 皆為病情改善的跡象。
An increased arterial-alveolar oxygen gradient (AaDO2) in a client with ARDS indicates worsening intrapulmonary shunting and impaired gas exchange, signaling that the condition is deteriorating. This finding suggests that despite supplemental oxygen, the arterial blood oxygen levels remain difficult to maintain due to significant lung injury. In contrast, decreased respiratory rate, improved oxygen saturation, and reduced crackles are indicators of clinical improvement.
美國重症監護病房（ICU）對 ARDS 的呼吸器管理與監測（包括 AaDO2）有嚴格的臨床路徑；台灣 ICU 也有類似標準，但實際執行可能因團隊與設備狀況略有差異。