冷水浸泡与高热治疗：以 38.6°C 作为直肠安全降温限度。
Cold-water immersion and the treatment of hyperthermia: using 38.6°C as a safe rectal temperature cooling limit.
机构信息
Human and Environmental Physiology Research Unit, University of Ottawa, ON, Canada.
出版信息
J Athl Train. 2010 Sep-Oct;45(5):439-44. doi: 10.4085/1062-6050-45.5.439.
CONTEXT
Cold-water immersion is recommended for the immediate field treatment of exertional heat stroke. However, concerns exist over potential overcooling of hyperthermic individuals during cold-water immersion.
OBJECTIVE
To evaluate the recommendation that removing previously hyperthermic individuals from a cold-water bath at a rectal temperature (T(re)) of 38.6°C would attenuate overcooling.
DESIGN
Controlled laboratory study.
SETTING
University research laboratory.
PATIENTS OR OTHER PARTICIPANTS
Participants included 6 men and 4 women (age = 22 ± 3 years, height = 172 ± 10 cm, mass = 67.8 ± 10.7 kg, body fat percentage = 17.1% ± 4.5%, maximum oxygen consumption = 59.3 ± 8.7 mL·kg(-1)·min(-1)).
INTERVENTION(S): After exercising at an ambient temperature of 40.0°C for 38.5 ± 9.4 minutes, until T(re) reached 39.5°C, participants were immersed in a 2.0°C circulated water bath until T(re) decreased to either 37.5°C or 38.6°C. Subsequently, participants were removed from the water bath and recovered for 20 minutes at an ambient temperature of 25°C.
MAIN OUTCOME MEASURE(S): Rectal and esophageal temperatures were measured continuously during the immersion and recovery periods.
RESULTS
Because of the experimental design, the overall time of immersion was greater during the 37.5°C trial (16.6 ± 5.7 minutes) than the 38.6°C trial (8.8 ± 2.6 minutes) (t(9) = -4.740, P = .001). During the recovery period after cold-water immersion, both rectal (F(1,9) = 50.540, P < .001) and esophageal (F(1,6) = 20.365, P = .007) temperatures remained greater in the 38.6°C trial than in the 37.5°C trial. This was evidenced by low points of 36.47°C ± 0.70°C and 37.19°C ± 0.71°C for rectal temperature (t(9) = 2.975, P = .016) and of 35.67°C ± 1.27°C and 36.72°C ± 0.95°C for esophageal temperature (t(6) = 3.963, P = .007) during the recovery period of the 37.5°C and 38.6°C trials, respectively.
CONCLUSIONS
Immersion for approximately 9 minutes to a rectal temperature cooling limit of 38.6°C negated any risk associated with overcooling hyperthermic individuals when they were immersed in 2°C water.
背景
冷水浸浴被推荐用于运动性热射病的现场即时治疗。然而，人们对在冷水中浸浴时高热个体可能过度冷却的问题存在担忧。
目的
评估将直肠温度（T(re)）为 38.6°C 的过热个体从冷水中移出的建议是否会减轻过度冷却。
设计
对照实验室研究。
地点
大学研究实验室。
患者或其他参与者
纳入 6 名男性和 4 名女性（年龄=22±3 岁，身高=172±10cm，体重=67.8±10.7kg，体脂百分比=17.1%±4.5%，最大摄氧量=59.3±8.7mL·kg(-1)·min(-1)）。
干预
在环境温度为 40.0°C 的情况下运动 38.5±9.4 分钟，直至 T(re)达到 39.5°C，参与者浸入 2.0°C 的循环水浴中，直到 T(re)降至 37.5°C 或 38.6°C。随后，将参与者从水中移出，并在环境温度为 25°C 的情况下恢复 20 分钟。
主要观察指标
直肠和食管温度在浸浴和恢复期间连续测量。
结果
由于实验设计，37.5°C 试验的总体浸浴时间（16.6±5.7 分钟）长于 38.6°C 试验（8.8±2.6 分钟）（t(9) =-4.740，P=.001）。在冷水浸浴后的恢复期，直肠（F(1,9)=50.540，P<.001）和食管（F(1,6)=20.365，P=.007）温度在 38.6°C 试验中均高于 37.5°C 试验。这一点从直肠温度的低体温点（36.47°C±0.70°C 和 37.19°C±0.71°C）（t(9)=2.975，P=.016）和食管温度的低体温点（35.67°C±1.27°C 和 36.72°C±0.95°C）（t(6)=3.963，P=.007）可以看出，这些低体温点分别出现在 37.5°C 和 38.6°C 试验的恢复期。
结论
直肠温度冷却至 38.6°C 左右的 9 分钟浸浴时间消除了将过热个体浸入 2°C 水中时过度冷却的任何风险。
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