Department of Anaesthesia & Intensive Care, Haukeland University Hospital, Bergen, Norway.
Mountain Medicine Research Group, The Norwegian Air Ambulance Foundation, Bergen, Norway.
Scand J Trauma Resusc Emerg Med. 2024 Apr 25;32(1):35. doi: 10.1186/s13049-024-01204-2.
Use of a vapor barrier in the prehospital care of cold-stressed or hypothermic patients aims to reduce evaporative heat loss and accelerate rewarming. The application of a vapor barrier is recommended in various guidelines, along with both insulating and wind/waterproof layers and an active external rewarming device; however, evidence of its effect is limited. This study aimed to investigate the effect of using a vapor barrier as the inner layer in the recommended "burrito" model for wrapping hypothermic patients in the field.
In this, randomized, crossover field study, 16 healthy volunteers wearing wet clothing were subjected to a 30-minute cooling period in a snow chamber before being wrapped in a model including an active heating source either with (intervention) or without (control) a vapor barrier. The mean skin temperature, core temperature, and humidity in the model were measured, and the shivering intensity and thermal comfort were assessed using a subjective questionnaire. The mean skin temperature was the primary outcome, whereas humidity and thermal comfort were the secondary outcomes. Primary outcome data were analyzed using analysis of covariance (ANCOVA).
We found a higher mean skin temperature in the intervention group than in the control group after approximately 25 min (p < 0.05), and this difference persisted for the rest of the 60-minute study period. The largest difference in mean skin temperature was 0.93 °C after 60 min. Humidity levels outside the vapor barrier were significantly higher in the control group than in the intervention group after 5 min. There were no significant differences in subjective comfort. However, there was a consistent trend toward increased comfort in the intervention group compared with the control group.
The use of a vapor barrier as the innermost layer in combination with an active external heat source leads to higher mean skin rewarming rates in patients wearing wet clothing who are at risk of accidental hypothermia.
ClinicalTrials.gov identifier: NCT05779722.
在院前急救冷应激或低体温患者时使用蒸汽屏障的目的是减少蒸发散热并加速复温。在各种指南中都推荐使用蒸汽屏障，同时使用隔热和防风/防水层以及主动外部复温设备；然而，其效果的证据有限。本研究旨在调查在现场将患者包裹在推荐的“玉米卷”模型中时，将蒸汽屏障用作内层对包裹低体温患者的效果。
在这项随机交叉现场研究中，16 名穿着湿衣服的健康志愿者在雪室中进行 30 分钟的冷却期，然后用模型包裹，模型包括主动加热源，要么使用（干预组）要么不使用（对照组）蒸汽屏障。测量模型中的平均皮肤温度、核心温度和湿度，并使用主观问卷评估颤抖强度和热舒适度。平均皮肤温度是主要结局，而湿度和热舒适度是次要结局。主要结局数据使用协方差分析（ANCOVA）进行分析。
我们发现，大约 25 分钟后，干预组的平均皮肤温度高于对照组（p<0.05），并且这种差异持续了整个 60 分钟的研究期间。60 分钟后，平均皮肤温度的最大差异为 0.93°C。在 5 分钟后，蒸汽屏障外的湿度水平在对照组中明显高于干预组。在主观舒适度方面没有显著差异。然而，干预组的舒适度有一致的增加趋势。
在穿着湿衣服有意外低体温风险的患者中，将蒸汽屏障用作最内层与主动外部热源结合使用可导致平均皮肤复温率更高。
ClinicalTrials.gov 标识符：NCT05779722。
