寒颤对呼吸道复温作用的影响

目的：检测寒颤对呼吸道复温的影响。方法：采用冷水浸泡降温和注射卡肌宁抑制寒颤的方法建立抑制寒颤的低体温犬模型。受试犬吸湿热空气（40．45℃,RH99．9％）及室温空气（19±1℃,RH30％～75％）复温各2h,不同温度空气复温的先后顺序随机安排。复温4h后,加压呼吸湿热空气复温使其恢复自主呼吸,继续呼吸湿热空气复温直至直肠温度（Tr）和食道温度（Te）恢复入水时温度。实验过程中采用间接测热法测定代谢产热量。结果：①抑制寒颤时,吸湿热空气2h可使Tr和Te平均每小时分别增高0．26～0．39℃和0．44—1．11℃,吸室温空气2h可使Tr和re平均每小时分别降低0．24-0．51℃和0．58～0．67℃,Tr和Te的变化与呼吸不同温度空气的先后顺序无关。②有寒颤、自主呼吸湿热空气时,Tr和Te的复温速度分别为2．26～2．33℃／h和1．96～2．38℃／h,较抑制寒颤、呼吸湿热空气时明显加快。③与抑制寒颤、加压呼吸湿热空气时的代谢产热量比较,受试犬恢复寒颤自主呼吸湿热空气时代谢产热量明显增高,使复温速度明显加快。结论：呼吸道复温有助于低体温机体复温。寒颤时机体代谢产热量明显增高,使复温速度明显加快。因此,检测呼吸道复温作用时应抑制寒颤,排除寒颤产热的干扰。

Effects of shivering on airway rewarming

Ahn： To investigate the effects of shivering on airway rewarming. Methods： The hypothennie dog model without shivering was established by immersing an anesthetized dog in cold water and administering atracurium to inhibit the dog shivering. The model dog respired warm fully humidified（40 - 45℃, RH99.9% ） air and room temperature air（ 19± 1 ℃, RH 30% - 75% ） to rewarm each for 2 hours, the priority of dif ferent temperature air respired was re＇ranged randomly.After rewarming for 4 hours, the relaxed dog breathed warm humidified air by positive pressure ventilation in order to restore its spontaneous respiratory. Then the dog continued to respire warm humidified air spontaneously until the esophageal（Te） and rectal temperature（Tr） of the dog achieved the same degrees as the dog was immersed in the water. The metabohc heat production was detected by indirect calorimetry during the experiment. Results： （1）When the shivering was inhibited, inhaling warm humidified air for 2 hours made the Tr and Te of the dogs increase 0.26 - 0.39℃ and 0.44 - 1.11% per hour respectively, inhaling air at room temperature for 2 hours made Tr and Te of the dogs decrease 0.24 - 0.51℃ and 0.58 - 0.67℃ per hour, respectively. And the changes in Tr and Te of the dogs were unrelated to the priority of inhaling air at different temperature. （2）When the dog with shivering respired spontaneously warm humidified air, the rewarming rates of Tr and Te were 2.26- 2.33℃/h and 1. 96- 2.38℃/h respectively, quicker than those of the dogs whose shivering was inhibited. （3）Compared with metabolic heat production of the unshivering dog respiring warm humidified air by positive pressure ventilation, that of the shivering dog respiring warm humidified air spontaneously increased outstandingly, shivering thermogenesis made the rewarming rates increased obviously. Conclusion： Airway rewarming is a method conducive to rewanning of hypothermia. When the body is shivering, the metabolic heat production increase