Kono M, Asakawa Y, Katagiri J, Yamada M, Sha M, Ohmura A
Department of Anesthesiology, Teikyo University School of Medicine, Mizonokuchi Hospital, Kawasaki.
Masui. 1995 Oct;44(10):1406-9.
We report a case of substantial rebreathing which occurred during the thoracoscopic bulla resection despite a normal FICO2 reading on capnogram. Early detection of inspiratory unidirectional valve malfunction as the cause of the rebreathing was only possible by careful observation of the capnogram pattern. During the course of one lung anesthesia, a rising end-tidal CO2 concentration (FETCO2) and a change in the pattern of the capnogram were observed. However, the lowest FICO2 value in the late phase of inspiration stayed below the alarm limit setting of rebreathing. For this reason, the capnograph failed to identify the beginning of inspiration and perceived the high FICO2 value in early inspiration as part of expiratory plateau. In case of the inspiratory valve malfunction, it is possible that analysis of the capnogram reveals underestimated FICO2.
我们报告了1例在胸腔镜下肺大疱切除术中发生大量重复吸入的病例，尽管二氧化碳波形图上的FICO2读数正常。只有通过仔细观察二氧化碳波形图模式，才能早期发现作为重复吸入原因的吸气单向阀故障。在单肺麻醉过程中，观察到呼气末二氧化碳浓度（FETCO2）升高以及二氧化碳波形图模式改变。然而，吸气后期的最低FICO2值仍低于重复吸入的警报限值设定。因此，二氧化碳监测仪未能识别吸气开始，并将吸气早期的高FICO2值视为呼气平台期的一部分。在吸气阀出现故障的情况下，分析二氧化碳波形图有可能发现FICO2被低估。
