Hara Naoki, Tanaka Tomohiro, Minami Toshiaki
Department of Anesthesiology, Osaka Medical College, Takatsuki 569-8686.
Masui. 2006 Feb;55(2):209-11.
A 44-year-old woman, ASA I, with breast cancer was scheduled for mastectomy. The anesthetic induction was performed by inhalation of 5% sevoflurane and 66% nitrous oxide in oxygen. After the loss of eyelash reflex assisted ventilation was initiated. At this point, the capnograph indicated inspired carbon dioxide tension of 18mmHg. Anesthetic machine check was soon carried out again. A visual check of non-return valves detected a plastic film, 18 x 21mm large, caught in the expiratory valve. This plastic film impaired complete occlusion of the orifice for the expiratory gas flow. As a result, the patient was rebreathing carbon dioxide. After removing it, the wave form of the capnograph was normalized and end-tidal carbon dioxide tension decreased immediately from 45mmHg to 33mmHg. As we did not detect any foreign matters at the non-return valves on anesthetic machine check before use, the plastic film might have already existed in the disposable corrugated tube before use. The capnograph is a useful device for detecting anesthetic circle system failure in such a case. It is important that the patients' airway is separated from the anesthetic circle system through the use of a filter to prevent foreign matter from being inhaled.
一名44岁、美国麻醉医师协会（ASA）分级为I级的乳腺癌女性患者计划接受乳房切除术。麻醉诱导通过吸入含5%七氟醚和66%氧化亚氮的氧气进行。睫毛反射消失后开始辅助通气。此时，二氧化碳波形图显示吸入二氧化碳分压为18mmHg。很快再次对麻醉机进行检查。通过目视检查止回阀发现一块尺寸为18×21毫米的塑料薄膜卡在呼气阀中。这块塑料薄膜妨碍了呼气气流孔的完全闭合。结果，患者在重复吸入二氧化碳。移除该塑料薄膜后，二氧化碳波形图恢复正常，呼气末二氧化碳分压立即从45mmHg降至33mmHg。由于在使用前对麻醉机进行检查时，我们在止回阀处未检测到任何异物，该塑料薄膜可能在使用前就已存在于一次性波纹管中。在这种情况下，二氧化碳波形图是检测麻醉回路系统故障的有用设备。重要的是，通过使用过滤器将患者气道与麻醉回路系统分开，以防止异物被吸入。
