Heating and Cooling Rates With an Esophageal Heat Exchange System
Heating and Cooling Rates With an Esophageal Heat Exchange System
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DOI：
10.1213/ane.0000000000002691
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发表时间：
2018-04-01
影响因子：
5.7
通讯作者：
Sessler, Daniel I.
中科院分区：
文献类型：
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作者：
Kalasbail, Prathima;Makarova, Natalya;Sessler, Daniel I.
背景技术背景：食管冷却装置通过食管热交换器循环温水或冷水，但对患者的加热和冷却效果仍然未知。因此，我们确定在加热和冷却时的热交换率。所有患者在非胸外科手术中均接受了气管内全麻。在冷却（交换器流体在7摄氏度）和加热（流体在42摄氏度）期间测量术中传热。每一个评估30分钟，随机确定初始条件，至少在麻醉诱导后40分钟开始。热传递率估计从流体流经食管热交换器和流入和流出温度。核心温度估计从零热通量温度计定位在foreground.RESULTS：平均热传递率在变暖过程中为18（95%置信区间，16-20）W，增加核心温度在0.5摄氏度/小时0.6摄氏度/小时（平均值+/-标准差）的速度。在冷却过程中，平均传热速率为-53（-59至-48）W，以0.9 ℃/h +/- 0.9 ℃/h的速率降低核心温度。结论：食管加温转移了18 W，远低于报告的80 W，下半身或上身强制通风罩。然而，食管加温可用于补充表面加温或在不适合表面加温的情况下提供加温。食管冷却传递的热量是加热的两倍多，这是由于冷却（29摄氏度）时核心和循环流体温度之间的差异比加热（6摄氏度）大得多。食管冷却提取的热量比血管内导管少，但可用于补充基于导管的冷却，或在适当的患者中可能替代它们。
BACKGROUND: The Esophageal Cooling Device circulates warm or cool water through an esophageal heat exchanger, but warming and cooling efficacy in patients remains unknown. We therefore determined heat exchange rates during warming and cooling.METHODS: Nineteen patients completed the trial. All had general endotracheal anesthesia for nonthoracic surgery. Intraoperative heat transfer was measured during cooling (exchanger fluid at 7 degrees C) and warming (fluid at 42 degrees C). Each was evaluated for 30 minutes, with the initial condition determined randomly, starting at least 40 minutes after induction of anesthesia. Heat transfer rate was estimated from fluid flow through the esophageal heat exchanger and inflow and outflow temperatures. Core temperature was estimated from a zero-heat-flux thermometer positioned on the forehead.RESULTS: Mean heat transfer rate during warming was 18 (95% confidence interval, 16-20) W, which increased core temperature at a rate of 0.5 degrees C/h 0.6 degrees C/h (mean +/- standard deviation). During cooling, mean heat transfer rate was -53 (-59 to -48) W, which decreased core temperature at a rate of 0.9 degrees C/h +/- 0.9 degrees C/h.CONCLUSIONS: Esophageal warming transferred 18 W which is considerably less than the 80 W reported with lower or upper body forced-air covers. However, esophageal warming can be used to supplement surface warming or provide warming in cases not amenable to surface warming. Esophageal cooling transferred more than twice as much heat as warming, consequent to the much larger difference between core and circulating fluid temperature with cooling (29 degrees C) than warming (6 degrees C). Esophageal cooling extracts less heat than endovascular catheters but can be used to supplement catheter-based cooling or possibly replace them in appropriate patients.