護理師照護一位使用嗎啡 PCA 的術後病人，下列哪項評估結果需要立即介入？

嗎啡（Morphine）經由病人自控止痛（PCA）輸注時，最嚴重的副作用為中樞神經抑制導致的呼吸抑制。呼吸頻率降至 8 次/分屬於危急徵象，代表病人已出現呼吸抑制，必須立即停止輸注、給予氧氣支持、評估生命徵象，並準備使用拮抗劑 Naloxone（納洛酮）以逆轉嗎啡作用，這是 ABC 原則中 Airway 與 Breathing 的優先處理。

When morphine is administered via patient-controlled analgesia (PCA), the most serious side effect is respiratory depression caused by central nervous system depression. A respiratory rate of 8 breaths/min is a critical sign, indicating that respiratory depression has occurred. The nurse must immediately stop the infusion, provide oxygen support, evaluate vital signs, and prepare to administer the antagonist naloxone to reverse the effects of morphine. This is the priority management of Airway and Breathing under the ABC principle.