Jantzen J P
Department of Anesthesiology, Johannes Gutenberg-University Medical School, Mainz, Germany.
Acta Anaesthesiol Belg. 1990;41(3):211-24.
Opinions vary on the monitoring requirements associated with low flow to closed circuit anesthesia. Fresh gas flow rate affects variables of anesthesia ventilation such as the time constant of the breathing system, the inspired concentrations of O2, N2O and anesthetic vapor and the potential for rebreathing. Furthermore, very low flow rates challenge the performance of rotameters and vaporizers. Consequently, the safe conduct of minimal flow or closed circuit anesthesia mandates oximetry, which should be redundant; the use of anesthetic agent monitors ("anesthetico-meters") is extremely helpful, and so is capnometry. However, none of these safety monitors is beyond the scope of the "essential requirements" proposed for anesthesia workstations by international standard-writing groups, such as CEN or ISO. It may hence be concluded that fresh gas flow rate does affect variables to be monitored, but it does not affect essential monitoring requirements.
对于低流量紧闭回路麻醉的监测要求，各方观点不一。新鲜气体流量会影响麻醉通气的各项变量，比如呼吸系统的时间常数、吸入的氧气、氧化亚氮和麻醉蒸汽浓度以及重复吸入的可能性。此外，极低的流量对转子流量计和蒸发器的性能也构成挑战。因此，实施最低流量或紧闭回路麻醉时必须进行脉搏血氧饱和度测定，这应该是冗余措施；使用麻醉剂监测仪（“麻醉计”）非常有帮助，二氧化碳监测也是如此。然而，这些安全监测设备都未超出国际标准编写组织（如CEN或ISO）对麻醉工作站提出的“基本要求”范围。因此可以得出结论，新鲜气体流量确实会影响需监测的变量，但不会影响基本监测要求。
