Author/Editor		Nagasaka, Tetsuo; Tanabe, Minoru; Hirashita, Masami
Title		Influence of changing intrathoracic pressure on emissary venous flow and selective brain cooling in hyperthermic conditions
Type		članek
Source		In: Hočevar A, Črepinšek Z, Kajfež-Bogataj L, editors. Biometeorology 14. Proceedings of the 14th international congress of biometeorology. Part 2. (Vol 2); 1996 Sep 1-8; Ljubljana. Ljubljana: Slovenian meteorological society,
Publication year		1996
Volume		str. 325-32
Language		eng
Abstract		We studied the possible influence of changing intrathoracic pressure on angular ocular and emissary venous flows and tympanic temperature (Tty) in hyperthermic subjects. Twelve men, aged 19-30 years, were exposed to heat by sitting in a box shape body warming unit with the head protruded. While esophageal temperature (Test) maintained at the level about 1 C higher than normal, the subjects were forced to breathe through a mounthpiece to a two-way valve producing airway resistance during inspiration (negative breathing) or expiration (positive breathing), and intrathoracic pressure (Ppl), angular-ophthalmic venous flow (Qov), forehead skin blood flow and sweating rate, and Tes and Tty were monitored continuously. The negative pressure breathing increased the negativity of Plp and increased angular-ophthalmic venous flow into the intracranium and produced a fall in Tty with no changes in Tes. The positive pressure breathing reduced the negativity of Ppl, during which the changes were in opposite directions. These results indicate that the more the negativity of intrathoracic pressue is, the more emissary flow and then the efficiency of selective brain cooling in hyperthermic human subjects.
Descriptors		HYPERTHERMIA, INDUCED ESOPHAGUS MANOMETRY RETINAL VEIN ADULT SKIN TEMPERATURE TYMPANIC MEMBRANE LASER-DOPPLER FLOWMETRY