Intraoperative pH values after N-acetylcysteine administration during liver transplantation

We investigated whether intraoperative administration of N-acetylcysteine (NAC) to liver transplant recipients affected pH values. This prospective, randomized, double-blind clinical trial included liver transplant recipients who were randomly assigned to NAC-treated (n=25) or placebo (n=25) groups. The NAC-treated group received 100 mg/kg dissolved in 5% dextrose over 15 minutes during the anhepatic phase, followed by a continuous infusion of 50 mg/kg in 5% dextrose during the next 24 hours. The placebo group received equal amounts of 5% dextrose solution during the same times. Peripheral blood samples were drawn in Ca2+-80 IU-containing syringes after induction of anesthesia (I-1), at 15 minutes into the anhepatic phase (I-2) prior to the administration of NAC or placebo, at 5 minutes before reperfusion (I-3), at 5 minutes after reperfusion (I-4), at 20 minutes after reperfusion (I-5), at 60 minutes after reperfusion (I-6), and at 1 hour after completion of the procedure (I-7). pH levels, which were determined using a radiometer ABL77 (Copenhagen, Denmark), were significantly lower among the NAC than the placebo group at I-4 (P=.027) and I-5 (P=.031). An early decrease in pH values was detected in the NAC-treated group at 5 minutes before reperfusion (I-3; P=.051). We concluded that intraoperative NAC administration during the anhepatic phase of liver transplantation significantly decreased recipient pH values at 5 and 20 minutes after reperfusion, a decrease that was detected at 5 minutes before reperfusion (I-3). The decrease seemed to be associated with NAC metabolism.