1992 Fiscal Year Final Research Report Summary
Emissary venous flow and selective brain cooling in hyperthermic human subjects.
| Project/Area Number |
02454128
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
環境生理学(含体力医学･栄養生理学)
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| Research Institution | Kanazawa University |
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Principal Investigator |
NAGASAKA Tetsuo Kanazawa University School of Medicine, Professor, 医学部, 教授 (80023646)
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| Co-Investigator(Kenkyū-buntansha) |
HIRASHITA Masami Kanazawa College of Economics, Professor, 教授 (30102007)
SAKURADA Sohtaro Kanazawa University School of Medicine, Instructor, 医学部, 助手 (00215691)
TANABE Minoru Kanazawa University School of Medicine, Instructor, 医学部, 助手 (20217110)
OSHIDO Osamu Kanazawa University School of Medicine, Associate Professor, 医学部, 助教授 (40175386)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Hyperthermia / Passive Body Warming / Exercise / Selective brain Cooling / Emissary veins / Sweating / Body Posture Change |
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| Research Abstract |
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.
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