麻醉機進吐氣循環系統進氣端之控制氣閥於全身麻醉誘導時閥片破裂導致高 碳酸血症之病例報告

Hypercapnia due to Rupture of the Unidirectional Valve in the Inspiratory Limb of the Breathing System after Induction of General Anesthesia-- A Case Report

麻醉機的進吐氣循環系統中，不管是吸入端或是吐出端之控制氣閥，若是失去正常之單一方向導流功能會造成二氧化碳的再次吸入，因而導致血中二氧化碳濃度上升。血中二氧化碳的氣體壓力增高會興奮交感神經系統的活性，因而造成嚴重後遺症諸如高心跳速率之心律不整及心肌缺血等，特別是當病人是冠心症患者，情況將更加危急。我們在此報告，一位三條冠狀動脈堵塞的冠心症患者，準備接受冠狀動脈繞道手術，于麻醉誘導時，發生了吐氣末端二氧化碳極高的危急狀況，文中將討論如何判斷這類危急狀況，併發症及其處置原則。

Malfunction of either inspiratory or expiratory check valve in a breathing circuit system may allow carbon dioxide (CO2) rebreathing and result in hypercapnia. The subsequent increase of PaCO2 may entail increased sympathetic activity which in turn causes serious problems such as tachyarrhythmia and myocardial ischemia, particularly in patients who have history of coronary artery disease (CAD). Here, we report an incident of rupture of the inspiratory valve in the breathing circuit which happened to a patient during induction of general anesthesia and eventuated in markedly heightened end-tidal CO2 (EtCO2) of the patient. The recognition, related complications and management of the inspiratory valve malfunction are discussed.