Barnes Stephen L, Branson Richard, Gallo Louis A, Beck George, Johannigman Jay A
USAF Center for Sustainment of Trauma and Readiness Skills, University of Cincinnati Division of Trauma/Critical Care, Cincinnati, OH 45267-0558, USA.
J Trauma. 2008 Feb;64(2 Suppl):S129-34; discussion S134-5. doi: 10.1097/TA.0b013e318160a5b4.
En-route care necessitates the evacuation of seriously wounded service members requiring mechanical ventilation in aircraft where low light, noise, vibration, and barometric pressure changes create a unique clinical environment. Our goal was to evaluate ventilatory requirements, oxygenation, and oxygen use in flight and assess the feasibility of a computer interface in this austere environment.
A personal computer was integrated with the pulse oximeter and ventilator data port used in aeromedical evacuation from Iraq to Germany. Ventilator settings, inspired oxygen (FiO2), tidal volume (VT), respiratory rate (RR), minute ventilation (VE), monitored values, heart rate (HR), and oxygen saturation (SpO2), were recorded continuously. Oxygen use was determined using the equation ([FiO2 - 21]/79) x (MVE). Additional data were obtained through the United States Air Force (USAF) Transcom Regulation and Command/Control Evacuation System (TRAC2ES) and the United States Army Institute of Surgical Research Joint Theater Trauma Registry databases.
During a 4 month time frame 117 hours of continuous recording was accomplished in 22 patients. Mean age was 27 +/- 9.83 and injury severity score military was 31.75 +/- 20.63 (range, 9-75). All patients survived transport. Mean values for ventilator settings were FiO2 (24-100%) of 49% +/- 13%, positive end-expiratory pressure of 6 +/- 2.5 (range, 0-17 cm H2O), RR of 15 +/- 2.4 (range, 10-22 breaths/min), and VT of 611 +/- 75 (range, 390-700 mL). Delivered VT in mililiter per kilogram was 6.9 +/- 1.30 and VE was 9.1 L/min +/- 1.4 L/min. Oxygen requirements for desired FiO2 and VE resulted in a mean oxygen usage of 3.24 L/min +/- 1.87 L/min (range, 1.6-10.2 L/min). There were 32 changes to FiO2, 18 changes to PEEP, 26 changes to RR, and 20 changes to VT during flight. Five patients under-went no recorded changes in flight. Three desaturation events (<90%) were recorded lasting 35, 115, and 280 seconds. Recorded ventilatory changes averaged less than 1 (0.82) per hour of recorded flight with FiO2 being the most common.
A computer interface is feasible in the austere aeromedical environment. Implications to military operations and civilian homeland defense include understanding casualty oxygen requirements for resource planning in support of aeromedical evacuation. Portable oxygen generation systems may be able to provide adequate oxygen flow for transport, reducing the need for compressed gas. Future studies of oxygen conservation systems including closed loop control of FiO2 are warranted.
途中护理需要将需要机械通气的重伤员空运至飞机上，而飞机上光线昏暗、噪音大、有振动且气压变化，营造了独特的临床环境。我们的目标是评估飞行中的通气需求、氧合和氧气使用情况，并评估在这种严峻环境下计算机接口的可行性。
一台个人计算机与从伊拉克空运至德国的航空医疗后送中使用的脉搏血氧仪和呼吸机数据端口相连。持续记录呼吸机设置、吸入氧浓度（FiO2）、潮气量（VT）、呼吸频率（RR）、分钟通气量（VE）、监测值、心率（HR）和血氧饱和度（SpO2）。使用公式（[FiO2 - 21]/79）×（MVE）确定氧气使用量。通过美国空军（USAF）运输司令部条例和指挥/控制后送系统（TRAC2ES）以及美国陆军外科研究所联合战区创伤登记数据库获取其他数据。
在4个月的时间内，对22名患者进行了117小时的连续记录。平均年龄为27±9.83岁，军事损伤严重程度评分为31.75±20.63（范围为9 - 75）。所有患者均在运输过程中存活。呼吸机设置的平均值为FiO2（24 - 100%）为49%±13%，呼气末正压为6±2.5（范围为0 - 17 cm H2O），RR为15±2.4（范围为10 - 22次/分钟），VT为611±75（范围为390 - 700 mL）。每千克体重的输送潮气量为6.9±1.30，VE为9.1 L/分钟±1.4 L/分钟。所需FiO2和VE的氧气需求量导致平均氧气使用量为3.24 L/分钟±1.87 L/分钟（范围为1.6 - 10.
