一位病人因大面積肺栓塞入院。護理師預期其初期的動脈血氣分析（ABG）結果最可能為何？
A client is admitted with a massive pulmonary embolism. The nurse expects to find which initial arterial blood gas (ABG) result?
- ApH 7.48, PaCO2 30 mmHg, HCO3 23 mEq/L✓ 正解pH 7.48、PaCO2 30 mmHg、HCO3 23 mEq/L
- BpH 7.30, PaCO2 50 mmHg, HCO3 24 mEq/LpH 7.30、PaCO2 50 mmHg、HCO3 24 mEq/L
- CpH 7.50, PaCO2 40 mmHg, HCO3 32 mEq/LpH 7.50、PaCO2 40 mmHg、HCO3 32 mEq/L
- DpH 7.35, PaCO2 45 mmHg, HCO3 28 mEq/LpH 7.35、PaCO2 45 mmHg、HCO3 28 mEq/L
肺栓塞急性發作時，雖然肺部氣體交換受阻（V/Q mismatch），但病人的第一反應通常是因低氧血症、疼痛與恐懼而引發「過度換氣」。過度換氣會導致二氧化碳（CO2）被大量排出，使 PaCO2 降低，進而引發呼吸性鹼中毒。因此初期 ABG 會顯示 pH 上升與 PaCO2 下降。只有當病情惡化到呼吸肌疲勞或大面積肺梗塞導致無法通氣時，才會轉變為呼吸性酸中毒。理解此生理演變對於早期識別病情惡化至關重要。護理師應密切觀察呼吸速率與型態的變化。
During the acute onset of pulmonary embolism, although pulmonary gas exchange is impaired (V/Q mismatch), the patient's initial response is typically hyperventilation triggered by hypoxemia, pain, and fear. Hyperventilation causes large amounts of carbon dioxide (CO2) to be exhaled, lowering PaCO2 and producing respiratory alkalosis. Therefore, the initial ABG shows an elevated pH and a decreased PaCO2. Only when the condition deteriorates to the point of respiratory muscle fatigue or extensive pulmonary infarction with inability to ventilate does it convert to respiratory acidosis. Understanding this physiologic progression is critical for early recognition of deterioration. The nurse should closely observe changes in respiratory rate and pattern.
在美國，Respiratory Therapist (RT) 負責 ABG 抽血與儀器判讀的比例很高，護理師需與 RT 緊密配合；台灣護理師常需在醫師指示下自行執行動脈抽血，且需具備獨立且精準判讀酸鹼失衡類型的能力。