一位有 COPD 病史的病人正以鼻導管給予 4 L/min 氧氣。護理師發現病人變得嗜睡且呼吸頻率為 8 次/分。最可能的原因是什麼？
A client with a history of COPD is receiving oxygen at 4 L/min via nasal cannula. The nurse notes the client is becoming lethargic and their respiratory rate is 8 breaths/min. What is the most likely cause?
- AThe client is finally resting comfortably病人終於舒適地休息了
- BCO2 narcosis due to high oxygen concentration✓ 正解因高氧濃度導致的二氧化碳麻醉
- CDevelopment of a pulmonary embolism發展出肺栓塞
- DWorsening of the underlying infection潛在感染惡化
慢性阻塞性肺病（COPD）病人的呼吸驅動力（Respiratory Drive）往往從正常的「高二氧化碳驅動」轉變為「低氧驅動（Hypoxic Drive）」。當給予高濃度氧氣（4 L/min 對某些 COPD 病人而言過高）時，血氧上升會消除此驅動力，導致病人呼吸變慢、變淺，進而造成二氧化碳蓄積（CO2 Retention），引發 CO2 昏迷（CO2 Narcosis）。臨床思路上，嗜睡與呼吸減慢是危急徵兆（ABC）。護理師應立即評估病人，並可能需要調降氧氣流量或改用 Venturi Mask 以精確控制氧氣濃度。
In clients with chronic obstructive pulmonary disease (COPD), the normal high-CO2 respiratory drive often shifts to a hypoxic drive. When a high oxygen concentration is administered (4 L/min may be too high for some COPD clients), the resulting rise in blood oxygen abolishes this drive, causing slow and shallow breathing, CO2 retention, and ultimately CO2 narcosis. Clinically, lethargy and a falling respiratory rate are alarming signs (ABCs). The nurse should immediately reassess the client and may need to reduce the oxygen flow rate or switch to a Venturi mask for precise oxygen control.
美國 NCLEX 非常強調「Venturi Mask」是 COPD 病人的首選，因為它能提供最精確的氧氣濃度。台灣臨床也遵循此原則，但在衛教時，美國更強調讓病人理解「Oxygen is a drug」，不可自行調高流量。