Mechanisms for Cooling the Brain Selectively and Hemodynamics of Emissary Venins

本研究的目的是探讨人体选择性脑降温机制的效率如何因体位、胸腔内压力和通气量的改变而受到使者静脉流量的影响。1.与仰卧位相比，直立位的鼓室流量较高，鼓室温度较低。6个ﾟ头低位时，变化方向相反。2.遮盖一侧角静脉和另一侧鼻腔水平的面静脉时，两侧鼓室温度均有不同程度的升高，且夹闭一侧的鼓室温度较高。3.在负压呼吸中，通过有吸气阻力的呼吸器或通过压力维持负压的储气罐，与对照组相比，使者流量增加，鼓室温度降低。4.过度换气时，鼓室温度降低。当吸入添加CO_2的空气时，观察到了这种情况，但在这种情况下，效果并不一致。5.当受试者通过一侧鼻孔呼吸时，另一侧鼻孔保持阻塞，同侧鼓室温度略有降低。所有这些结果表明，增强使者静脉血流对于提高人类热疗中选择性脑降温的效率是必要的。

The purpose of this study was to investigate how the efficiency of selective brain cooling mechanisms in humans are influenced by the change in emissary venous flow due to the change in posture, intrathoracic pressure and ventilation. 1. Compared with in supine body position, emissary flow was higher and tympanic temperature became lower in upright position. With 6ﾟ-head down position, the changes were in opposite directions. 2. While occuluding the angular vein of one side and the facial vein at the alinasal level of another side, there occurred a disrepancy of tympanic temperatures in both sides, higher in the side where the angular vein was occluded. 3. In a negative breathing through a respirator with an inspiratory resistance or through a tank whose pressure was maintained negative, emissary flows increased and tympanic temperature became lower compared with the controls. 4. With hyperventilation, tympanic temperature became lower. The was observed when CO_2-added air was inspired, but the effect was not consistent in this case. 5. When the subject breathed through a nostril of one side, that of the other side was kept obstructed, the ipsilateral tympanic temperature became slightly lower. All these results suggest that enhancement of emissary venous flow was necessary important to increase efficiency of selective brain cooling in humans during hyperthermia.