[Effect of acute moderate isovolumic hemodilution on the pharmacokinetics of vecuronium].

[OBJECTIVE] To determine the effect of acute moderate isovolemic hemodilution on pharmacokinetics of vecuronium.

[METHODS] Twenty-six adult patients, ASA grade I, undergoing elective plastic surgery, were randomly divided equally into the control and hemodilution group. The blood samples were taken for 5 hours following intravenous bolus of 100 micrograms/kg of vecuronium in two groups. The plasma concentrations of vecuronium were determined with an improved fluorometry and the pharmacokinetic parameters were obtained by fitting the data with a 3P87 program.

[RESULTS] The disposition of vecuronium can be best described by a three compartment open model. As comparison with the control group, the values of Vc and Vdss in hemodilution group were greater than that in the control, while T1/2 beta was markedly prolonged in this group. There were no significant differences in T1/2 phi, T1/2 alpha, K12, K21, K13, K31, K10, MRT, AUC, and Cl between the two groups.

[CONCLUSION] Acute moderate isovolemic hemodilution could change the pharmacokinetics of vecurinium, particularly in distribution and elimination phases.