Autoregulation of cerebral blood flow surrounding acute (6 to 22 hours) intracerebral hemorrhage

Background: Arterial hypertension is common in the first 24 hours after acu te intracerebral hemorrhage (ICH), Although increased blood pressure usuall y declines to baseline values within several days, the appropriate treatmen t during the acute period has remained controversial, Arguments against tre atment of hypertension in patients with acute ICR are based primarily on th e concern that reducing arterial blood pressure will reduce cerebral blood flow (CBF). The authors undertook this study to provide further information on the changes in whole-brain and periclot regional CBF that occur with ph armacologic reductions in mean arterial pressure (MAP) in patients with acu te ICH, Methods: Fourteen patients with acute supratentorial ICH 1 to 45 mt in size were studied 6 to 22 hours after onset. CBF was measured with PET and 150-water. After completion of the first CBF measurement, patients were randomized to receive either nicardipine or labetalol to reduce MAP by 15% , and the CBF study was repeated. Results: MAP was lowered by -16.7 +/- 5.4 % from 143 +/- 10 to 119 +/- 11 mm Hg. There was no significant change in e ither global CBF or periclot CBF. Calculation of the 95% CI demonstrated th at there is less than a 5% chance that global or periclot CBF fell by more than -2.7 mL 100 g(-1) min(-1). Conclusion: In patients with small- to medi um-sized acute ICH, autoregulation of CBF was preserved with arterial brood pressure reductions in the range studied.