The Long-Term Use of Pipecuronium in Cardiac and Esophageal Surgery Patients

Summary

We studied 24 patients undergoing cardiac surgery or esophagectomy, and necessitating postoperative mechanical ventilation. The initial and maintenance doses of pipecuronium (0.08 mg/kg which is approximately 2 × ED₉₅, and 0.04 mg/kg, respectively) were given during the surgery, and the continuous intravenous infusion of pipecuronium was given in the ICU after surgery. The neuromuscular blockades (NMBs) produced by the relaxant were evaluated with an evoked compound electromyogram. The plasma concentrations of pipecuronium were determined 5 min after the administration of pipecuronium, at 10 % recovery from the complete NMB during surgery and one time a day during the continuous intravenous infusion of the drug in the ICU. The clinical durations of the maintenance dose of pipecuronium in the hypothermic state (core temperature 25.8±0.3° C) during cardiopulmonary bypass (CPB) and in the normothermic states, before and after CPB (core temperature 36.0±0.2°C and 35.7±0.3°C) were 295±18, 107±13 and 143±18 minutes, respectively. The repeated administration of the maintenance dose did not produce prolongation of the clinical duration in the normothermic state of esophagectomy patients. The required infusion rates of pipecuronium were 0.035±0.004 mg/kg/h (0.02–0.06 mg/kg/h) in the ICU. The plasma concentrations of pipecuronium 5 min after the administration of it in cardiac surgery and esophagectomy patients were 508.0±71.3 ng/ml, 524.0±45.0 ng/ml in the initial dose, and 418.3±31.3 ng/ml, 413.7±31.5 ng/ml in the maintenance dose, respectively. The plasma concentrations of pipecuronium for 90% block in hypothermic state of cardiac surgery patients and in normothermic state of esophagectomy patients were 38.8±4.9 ng/ml (23.3–59.8 ng/ml) and 117.0±10.3 ng/ml (50.2–192.1 ng/ml), respectively.