Postoperative morphine concentration in infants with or without biliary atresia and its association with hepatic blood flow.

We measured pre-operative hepatic blood flow and postoperative morphine concentration in infants with or without biliary atresia. Thirty-four infants (0-3 months) with biliary atresia undergoing portoenterostomy (Kasai operation) were included and hepatic blood flow was assessed by magnetic resonance imaging before surgery in 12 of them. Sixteen subjects (0-3 months) without liver disease undergoing abdominal or pelvic surgery acted as controls and six of them had hepatic blood flow assessed. Intravenous morphine (8 μg.kg(-1).h(-1)) was administered to all patients postoperatively. The median (IQR [range]) relative hepatic blood flow was 3.51 (2.72-3.88 [1.68-4.43]) with and 3.15 (2.66-4.42 [2.30-5.01]) without biliary atresia (p = 0.851). The median (IQR [range]) morphine concentration after 24 h infusion was 5.9 (4.5-16.4 [2.9-42.2]) ng.ml(-1) and 6.4 (3.2-12.0 [1.9-48.6]) ng.ml(-1) , respectively (p = 0.460). An inverse regression relation was found between the morphine concentration and the hepatic perfusion index (R(2) = 0.519, p = 0.001). Compensatory increases in hepatic arterial blood flow maintain the total hepatic blood flow in infants with biliary atresia.