Kim Tae W, Wingate Jamie R, Fernandez Allison M, Whitaker Emmett, Tham Robert Q
Department of Anesthesiology and Critical Care Medicine, Johns Hopkins Hospital, Baltimore, MD, USA.
Paediatr Anaesth. 2013 Dec;23(12):1124-30. doi: 10.1111/pan.12234. Epub 2013 Aug 16.
BACKGROUND/AIM: Malignant hyperthermia susceptible patients may experience a fatal reaction to volatile anesthetic gases. This study sought to determine the washout characteristics of desflurane, sevoflurane, and isoflurane from the Aisys® , Avance® , and Aestiva® anesthesia machines. (GE Healthcare, Madison, WI, USA).
All machines were inspected by a GE Healthcare engineer prior to testing. The machines were primed with desflurane 7 vol%, sevoflurane 2.5 vol%, and isoflurane 1.2 vol% on three separate occasions for 2 h each with each gas. The Aisys® and Avance® were tested with and without an Advanced Breathing System (ABS™ , GE Healthcare, Madison, WI, USA). The Aestiva® was tested without modification to its breathing system. Additionally, the Aisys was evaluated with desflurane 1.2 vol% and the Avance with a preflushed fresh gas line was tested with an autoclaved ABS. After priming, disposable components of the patient breathing system were replaced. The fresh gas flow was increased to 15 lpm. Gas measurements were recorded until the concentration was 4 parts per million (p.p.m).
The fastest median washout time was achieved by the Avance in 3 min or less without an ABS or with an autoclaved ABS. The longest median time was 35 min for the Aestiva® . Clearance of desflurane was the most time consuming for all machines.
This study demonstrates that saturated vapor pressure and priming concentration exert a greater effect on washout times than gas solubility. The Aisys utilizes an electronic vaporizer system that may expose the breathing system to retained saturated vapor. The breathing systems for all machines may hinder washout of gases.
背景/目的：恶性高热易感患者可能会对挥发性麻醉气体产生致命反应。本研究旨在确定地氟烷、七氟烷和异氟烷从Aisys®、Avance®和Aestiva®麻醉机（美国威斯康星州麦迪逊市通用电气医疗集团）中的清除特性。
在测试前，所有机器均由通用电气医疗集团的工程师进行检查。在三个不同的时间段，分别用7%体积分数的地氟烷、2.5%体积分数的七氟烷和1.2%体积分数的异氟烷对机器进行预充，每种气体预充2小时。Aisys®和Avance®在有和没有高级呼吸系统（ABS™，美国威斯康星州麦迪逊市通用电气医疗集团）的情况下进行测试。Aestiva®在未对其呼吸系统进行改装的情况下进行测试。此外，Aisys用1.2%体积分数的地氟烷进行评估，Avance用预冲洗的新鲜气体管路并搭配经高压灭菌的ABS进行测试。预充后，更换患者呼吸回路的一次性部件。将新鲜气体流量增加到15升/分钟。记录气体测量值，直到浓度达到百万分之四（ppm）。
在没有ABS或使用经高压灭菌的ABS的情况下，Avance的中位清除时间最快，在3分钟或更短时间内。Aestiva®的最长中位时间为35分钟。所有机器中，地氟烷的清除最耗时。
本研究表明，饱和蒸气压和预充浓度对清除时间的影响大于气体溶解度。Aisys采用电子蒸发器系统，这可能会使呼吸回路暴露于残留的饱和蒸气中。所有机器的呼吸回路可能会阻碍气体的清除。
