Cerebral autoregulation during whole-body hypothermia and hyperthermia stimulus

The purpose of the study contained herein was to investigate the effects of old traditional physiotherapeutic treatments on cerebral autoregulation. T reatment consisted of complete body immersion in cold or warm water baths. Fifteen volunteers were investigated by means of transcranial Doppler sonog raphy and a servo-conf rolled noninvasive device for blood pressure measuri ng. One group of 8 volunteers (mean age, 27.2 +/- 3.5 yr; gender, 3 females /5 males) was subjected to cold baths of 22 degrees C for 20 min Another gr oup of 7 volunteers (mean age, 52.1 +/- 8.5 yr; gender, 4 females/3 males) took hyperthermic baths at rising water temperatures from 36 degrees to 42 degrees C, increased by 1 degrees C every 5 min. Each volunteer in both gro ups underwent autoregulation tests two to four times before, during, and af ter the thermic bath. Dynamic autoregulation was measured by the response o f cerebral blood flow velocity to a transient decrease of the mean arterial blood pressure, induced by rapid deflation of thigh cuffs. The autoregulat ion index, i.e., a measure of the speed of change of cerebral autoregulatio n, was used to quantify the response. Further parameters were core temperat ure, blood pressure (mm Hg) and CO2et. During hypothermic baths, cope tempe rature decreased by 0.3 degrees C (P = 0.001), measured between preliminary phase and the end of the bath; the autoregulation index decreased signific antly (P < 0.05) from 5.3 before the bath to 4.25 during the bath. During h yperthermic baths, the autoregulation index increased from 6.0 to 7.5 and 8 .9 (P < 0.001), with an increase of core temperature of 0.4 degrees C. The main cerebral autoregulation system is dependent on changes of core tempera ture, provoked by hypothermic or hyperthermic whole-body thermostimulus. Ap plication of hyperthermic baths increased the autoregulation index, and hyp othermic baths decreased the autoregulation index. Further studies are need ed to prove the positive effects of thermo-stimulating wafer applications o n cerebral hemodynamics in patients with cerebral diseases.