DOSE REQUIREMENTS AND PLASMA CONCENTRATIONS OF PIPECURONIUM DURING BILATERAL RENAL EXCLUSION AND ORTHOTOPIC LIVER TRANSPLANTATION IN PIGS

We have studied five pigs undergoing bilateral clamping of therenal pedicles, seven pigs undergoing orthotopic liver transplantationand three control animals without surgery in order to examinethe roles of the kidney and liver in the plasma clearance ofpipecuronium. An i.v. infusion of pipecuronium was controlledto maintain a constant 90–95 % twitch depression throughoutthe investigation. The right sciatic nerve was stimulated continuouslywith supra-maximal stimuli at 0.1 Hz and the force of the correspondingevoked isometric muscle contraction was recorded continuously.Control pigs needed an infusion rate of pipecuronium 8–10.7µg kg^–1 min^–1. In the renal group, it wasnecessary to reduce the infusion rate of pipecuronium by about25% after clamping both renal vascular pedicles (P < 0.05compared with controls); in pigs undergoing liver transplantation,it was necessary to reduce the rate by approximately 80% afterclamping hepatic vessels (P < 0.05 compared with controlsand from the period after clamping of renal vessels). Afterhepatic recirculation, the infusion rate of pipecuronium wasincreased progressively to a rate which corresponded to 50%of baseline values (P < 0.05 compared with the anhepaticphase and from controls). Plasma concentrations of pipecuroniumwere comparable in the three animal groups and did not changesignificantly during the study. These data suggest that theliver plays a more important role than the kidney in the plasmaclearance of pipecuronium in pigs.