Emissary venous flow and selective brain cooling in hyperthermic human subjects.

我们测量了男性志愿者在全身热疗期间的皮肤血流量和头部出汗率、角眼和乳突静脉、食道、鼓室的血流量以及平均皮肤温度。1. 当眼角流受阻8 ~ 10 min，核心温度仍在上升时，鼓室温度的上升速度比前增加，而食管温度的上升速度没有变化。当皮肤压迫面静脉增加眼角血流时，鼓室温度的上升速度比前降低，但食管温度没有变化。2. 在被动取暖和运动中，角眼静脉血流急剧增加的鼓室温度是相同的。3. 化妆浓的受试者的食道和鼓室之间的温度差比化妆淡的受试者小。4. 当体位由仰卧位变为俯卧位时，随着鼓室温度上升速率的降低，角状眼和乳突血管的血流量增加。当受试者保持仰卧位时，[Tes-Tty]在整个全身热疗期间保持小。5. 在体温升高过程中，平均皮肤温度达到37-38ºC，即使核心温度仍在上升，面部皮肤血流量和出汗率也达到平台。我们认为，只要脑温度处于热损失反应最高水平的温度范围内，通过选择性脑冷却来降低脑温度不会抑制热损失反应。根据这些结果，我们得出结论，选择性大脑冷却对人类来说是可能的，也是重要的。选择性脑冷却是通过静脉血的流入来实现的，静脉血在头皮和面部通过汗水的蒸发冷却，通过输送静脉和眼静脉进入颅内。

We measured skin blood flow and sweating rate of the head, blood flow in the angular oculi and mastoid emissary veins, esophageal, tympanic, and mean skin temperatures during whole body hyperthermia in male volunteers. 1. When angular oculi flow was obstructed for 8-10 min while core temperatures were still rising, the rate of rise in tympanic temperature increased than before but that in esophageal temperature did not change. When angular oculi flow was increased by skin compression over the facial veins at an alinasl level, the rate of rise in tympanic temperature decreased than before but esophageal temperature did not change. 2. Tympanic temperature at which a sharp increase of flow occurred in angular oculi veins was the same in either passive body warming or exercise. 3. Temperature difference between the esophagus and the tympanum [Tes-Tty] became less in the subjects with heavy make-up than in those without. 4. When body posture was changed from supine to a 30ﾟ head-up position, blood flows in angular oculi and mastoid emissary veins were increased with a fall in the rate of rise in tympanic temperature. When the subjects remained supine, [Tes-Tty] remained small for the entire period of whole body hyperthermia. 5. During body warming, mean skin temperature reached 37-38ﾟC and skin blood flow and sweating rate of the face reached a plateau even when core temperatures were still rising. We suggest that the fall in brain temperature by selective brain cooling would not suppress the heat loss responses as far as brain temperature is within the range of temperature at which the heat loss responsesare at their maximum level. From these results, we conclude that selective brain cooling is possible and important in humans. Selective brain cooling is achieved by inflow of venous blood, cooled on the scalp and face by evaporation of sweat, through the emissary and ophtahalmic veins into the intracranium.