Abstract: The objective was to study the relationship of local brain temperature and temperatures measured at standard extracranial monitoring sites in neurosurgical patients during mild hypothermia. In ten ASA patients(gradeⅠ～Ⅱ)scheduled for craniotomy, the esophageal temperature(t_eso), nasopharyngeal temperature(t_nas)and local brain surface temperature(t_brain)were monitored continuously. Local t_brain was monitored at dura opening. At dura opening, local t_brain was lower than t_eso and t_nas(P<0.01), The maximal difference was 2.7 ℃. Local t_brain correlated closely to esophageal(r=0.935)and nasopharyngeal temperature(r=0.927). Local t_brain was mainly influences by esophageal temperature, body surface and time, since the brain surface was exposed was to air. Local t_brain correlated closely to esophageal and nasopharyngeal temperature at dura opening in neurosurgical patients during mild hypothermia, but it is necessary to measure local t_brain for some critical neurosurgery directly.

Key words: brain temperature, monitoring, craniotomy, hypothermia induced