Cerebral autoregulation in patients with end-stage liver disease

Objective The aim of the present study was to determine whether cerebral autoregulation is absent in patients with end-stage liver disease. Design A prospective physiological study Methods Thirty patients, 15 female (median age 50 years, range 33-74), with biopsy-proven cirrhosis (4 Child-Pugh class B, 26 Child-Pugh class C), had their cerebral perfusion evaluated using mean flow velocity (V-mean) in the middle cerebral artery as measured by transcranial Doppler sonography. Mean arterial pressure (MAP) was raised by intravenous noradrenaline (5-30 mu g/min). Nine patients had no clinical signs of hepatic encephalopathy (HE), three were in HE stage 1, four in HE stage 2, four in HE stage 3 and ten in HE stage 4, respectively. Results Cerebral autoregulation was impaired in 13 patients, as V-mean increased from 47 (26-88) to 60 (36-109) cm/s during a rise in MAP from 61 (47-99) to 82 (65-121) mmHg. V-mean remained unchanged (preserved cerebral autoregulation) at 56 (30-119) cm/s in 17 patients when MAP was raised from 74 (59-90) to 95 (81-129) mmHg. Cerebral autoregulation was lost in 8/10 patients with HE stage 4 and only in 2/9 patients without HE (P = 0.023). The duration of HE stage 1-4 before the autoregulation study was identical for patients with preserved cerebral autoregulation compared to patients with impaired cerebral autoregulation, 5 (2-30) versus 6 (2-35) days, respectively. Baseline values of MAP were significantly lower in patients with no cerebral autoregulation compared to patients with preserved cerebral autoregulation, 61 (47-99) versus 74 (59-90) mmHg (P = 0.012). All other baseline values in the two groups were similar, including PaCO2, albumin, bilirubin, international normalization ratio, galactose elimination capacity, Child - Pugh class and age. Conclusion Cerebral autoregulation is preserved in most patients with end-stage liver disease. In patients with hepatic encephalopathy and low MAP, however, cerebral autoregulation is impaired. Eur J Gastroenterol Hepatol 12:767-771 (C) 2000 Lippincott Williams & Wilkins.