— 生理適應 · MEDIUM · MCQ —
COPD 病人使用 2 L/min 鼻導管給氧。護理師發現病人變得嗜睡且呼吸速率降至 8 次/分。最可能的原因是什麼？
A client with chronic obstructive pulmonary disease (COPD) is receiving oxygen at 2 L/min via nasal cannula. The nurse notes the client is becoming lethargic and respiratory rate has dropped to 8 breaths/min. What is the most likely cause?
- AOxygen-induced CO2 retention (hypoxic drive suppression)✓ 正解氧誘發之二氧化碳滯留（缺氧驅動受抑制）
- BImprovement in oxygenation氧合改善
- CWorsening of the underlying infection潛在感染惡化
- DNormal response to oxygen therapy對氧療之正常反應
— Explanation · 中文詳解 —
部分慢性 COPD 病人依賴低氧（Hypoxic drive）來驅動呼吸。當給予過多氧氣使 SpO2 過高時，大腦會認為不需要呼吸，導致呼吸抑制和二氧化碳蓄積（CO2 narcosis），進而引發嗜睡。這並非好轉（B）或正常反應（D）。
Some chronic COPD patients rely on a hypoxic drive to stimulate breathing. Excessive oxygen administration that raises SpO2 too high removes this drive, leading to respiratory depression and CO2 narcosis with lethargy. This is not improvement (B) or a normal response (D).
✦ 台美臨床差異
兩地均強調 COPD 的低流量給氧原則（通常 SpO2 維持 88-92% 即可）。