背景:Diamedica引气蒸发器2(DDV2)是英国国防医疗服务部门使用的七氟醚蒸发器,用于提供部署的挥发性全身麻醉。防御麻醉系统采用带有涡轮驱动呼吸机的DDV2作为“推倒”蒸发器,从制造商的设计修改。我们调查了七氟醚在不同分钟体积(MV)下的输送,蒸发器设置和温度在这个配置。
方法:一系列DDV2设置(1%,2%,3%,4%和诱导)和MV(2、4、6和8L/min,每分钟12次通风)在两个环境温度(20和30±3°C)下进行了30分钟的测试。一个补充实验,模拟损伤控制手术期间的麻醉,也完成了,其中DDV2设定为2%,MV为6L/min,持续90分钟。
结果:在两个实验中,观察到七氟烷递送的两个不同阶段,一个“清洗阶段”,后跟一个“维护期”。洗入阶段通常持续少于5分钟。在维护期间,在低MV和蒸发器设置DDV2提供了一个恒定的输出,而在更高的MV和设置下,蒸汽产量可预见地下降。在20±3°C时,使用临床实践中可能遇到的DDV2设置,七氟醚给药在设定的20%以内.更高的蒸发器设置,MV和温度导致蒸发器设置和试剂输送之间的较大变化。这种变化由DDV2的不完全温度补偿来解释。
结论:DDV2在一系列设置下可预测地发挥作用,MV和温度。防御麻醉配置中的麻醉递送类似于先前在抽出配置中描述的麻醉递送。该设备被发现是可靠和坚固的。这项实验工作支持继续使用防御麻醉系统来提供和培训已部署的全身麻醉。
BACKGROUND: The Diamedica Draw-over Vaporiser 2 (DDV2) is the sevoflurane vaporiser used by the UK Defence Medical Services to provide deployed volatile general anaesthesia. The Defence Anaesthesia System employs the DDV2 with a turbine-driven ventilator as a \'push-over\' vaporiser, a modification from the manufacturer\'s design. We investigated sevoflurane delivery at varying minute volumes (MVs), vaporiser settings and temperatures in this configuration.
METHODS: A range of DDV2 settings (1%, 2%, 3%, 4% and induction) and MVs (2, 4, 6 and 8 L/min at 12 ventilations per minute) were tested at two ambient temperatures (20 and 30±3°C) over 30 min. A supplemental experiment, simulating anaesthesia during damage control surgery, was also completed, where he DDV2 was set to 2% with a 6 L/min MV for 90 min.
RESULTS: In both experiments, two distinct phases of sevoflurane delivery were noted, a \'wash-in phase\' followed by a \'maintenance period\'. The wash-in phase normally lasted less than 5 min. During the maintenance period at low MVs and vaporiser settings the DDV2 delivered a constant output, while at higher MVs and settings vapour output fell predictably. At 20±3°C, using DDV2 settings likely to be encountered in clinical practice, sevoflurane delivery was within 20% of that set. Higher vaporiser settings, MVs and temperatures resulted in greater variation between vaporiser setting and agent delivery. This variation is explained by the incomplete temperature compensation of the DDV2.
CONCLUSIONS: The DDV2 functions predictably at a range of settings, MVs and temperatures. Anaesthetic delivery in the defence anaesthesia configuration is like that previously described in the draw-over configuration. The equipment was found to be reliable and robust. This experimental work supports the continued use of the Defence Anaesthesia System for the delivery of and training in deployed general anaesthesia.