The pharmacokinetics of d-tubocurarine with surgery involving salvaged autologous blood

The disposition of d-tubocurarine (dTc) was assessed when a bolus and infusion dosage regimen was used to obtain relaxation during major orthopedic surgery on the spine. Renal clearance of dTc was 0.63 ± 0.23 ml.min^-1.kg^-1 and was correlated with creatinine clearance. Total plasma clearance of 1.21 ± 0.40 ml.min^-1.kg^-1 was lower than that found in many previous studies, and the predetermined continuous dTc infusion produced an apparent plateau in plasma concentrations of 1.8 ± 0.3 μg.ml^-1. Despite the operative blood loss, these concentrations were greater than anticipated and were associated with a more intense neuromuscular blockade than the infusion was designed to produce. Autologous blood transfusion was used to reduce the reliance on homologous donor blood, and the erythrocytes from the 2.2 ± 1.2 l of blood loss during the procedure were reinfused after intraoperative salvage, washing, and centrifugation. With 80 ± 23 mg dTc administered, 1.4 ± 0.8% was recovered from the fluid discarded after centrifugation. These results indicate that even massive intraoperative blood loss will not entail a significant reduction in the amount of dTc present in the body.