Wadhwa Anupama, Komatsu Ryu, Orhan-Sungur Mukadder, Barnes Pamela, In JangHyeok, Sessler Daniel I, Lenhardt Rainer
Outcomes Research Institute, University of Louisville, Louisville, Kentucky, USA.
Anesth Analg. 2007 Dec;105(6):1681-7, table of contents. doi: 10.1213/01.ane.0000289534.65690.ce.
Newer circulating-water systems supply more heat than forced-air, mainly because the heat capacity of water is much greater than for that of dry warm air and, in part, because they provide posterior as well as anterior heating. Several heating systems are available, but three major ones have yet to be compared directly. We therefore compared two circulating-water systems with a forced-air system during simulation of upper abdominal or chest surgery in volunteers.
Seven healthy volunteers participated on three separate study days. Each day, they were anesthetized and cooled to a core temperature near 34 degrees C, which was maintained for 45-60 min. They were then rewarmed with one of three warming systems until distal esophageal core temperature reached 36 degrees C or anesthesia had lasted 8 h. The warming systems were 1) energy transfer pads (two split torso pads and two universal pads; Kimberly Clark, Roswell, GA); 2) circulating-water garment (Allon MTRE 3365 for cardiac surgery, Akiva, Israel); and 3) lower body forced-air warming (Bair Hugger #525, #750 blower, Eden Prairie, MN). Data are presented as mean +/- sd; P < 0.05 was statistically significant.
The rate of increase of core temperature from 34 degrees C to 36 degrees C was 1.2 degrees C +/- 0.2 degrees C/h with the Kimberly Clark system, 0.9 degrees C +/- 0.2 degrees C/h with the Allon system, and 0.6 degrees C +/- 0.1 degrees C/h with the Bair Hugger (P = 0.002).
The warming rate with the Kimberly Clark system was 25% faster than with the Allon system and twice as fast as with the Bair Hugger. Both circulating-water systems thus warmed hypothermic volunteers in significantly less time than the forced-air system.
新型循环水系统比强制空气系统提供的热量更多，主要是因为水的热容量远大于干暖空气，部分原因还在于它们能同时提供前后部加热。现有多种加热系统，但三种主要系统尚未直接比较。因此，我们在志愿者模拟上腹部或胸部手术期间，将两种循环水系统与一种强制空气系统进行了比较。
七名健康志愿者在三个不同的研究日参与实验。每天，他们接受麻醉并冷却至接近34摄氏度的核心体温，维持45 - 60分钟。然后用三种加热系统之一进行复温，直至食管远端核心体温达到36摄氏度或麻醉持续8小时。加热系统分别为：1）能量传递垫（两个分体躯干垫和两个通用垫；金佰利公司，佐治亚州罗斯韦尔）；2）循环水衣（用于心脏手术的Allon MTRE 3365，以色列阿基瓦）；3）下半身强制空气加热（Bair Hugger #525，#750吹风机，明尼苏达州伊甸草原）。数据以平均值±标准差表示；P < 0.05具有统计学意义。
使用金佰利系统时，核心体温从34摄氏度升至36摄氏度的速率为1.2摄氏度±0.2摄氏度/小时，使用Allon系统时为0.9摄氏度±0.2摄氏度/小时，使用Bair Hugger时为0.6摄氏度±0.1摄氏度/小时（P = 0.002）。
金佰利系统的升温速率比Allon系统快25%，是Bair Hugger的两倍。因此，两种循环水系统使体温过低的志愿者复温的时间均明显少于强制空气系统。
