Abstract
Alcohol intoxication increases cerebral blood flow from 8 to 24 %. Alcohol intoxication does not impair dynamic cerebral autoregulation.
Caffeine (300 mg per oral) decreases cerebral blood flow by 20 %. Without CO2 influence, caffeine decreases cerebral blood flow from 10 to 20 %.
CO2 is a strong regulator of cerebral blood flow (through the regulation of the tone of cerebral vessels). Cerebral vasomotor reactivity in healthy humans is 86.5 ± 19.1, and CO2 reactivity is 3.0 ± 0.6 %/mmHg.
Cerebral autoregulation is significantly impaired during hypercapnia (autoregulation index decreases from baseline values of 4 ± 0.8 to 0.9 ± 0.9). Increase of etCO2 by 1mmHg decrease ARI by 8.24 %.
TBI cause significant impairment of cerebral autoregulation. Cerebral autoregulation may respond with asymmetric reaction – reacts more efficiently against hypertension and hyperperfusion than against hypoperfusion.
Caffeine and CO2 offer the possibility of therapeutic manipulation in cases of traumatic vasoparalysis.