Postoperative residual paralysis and respiratory status: a comparative study of pancuronium and vecuronium

The objective of this prospective double-blind study was to determine whether postoperative residual paralysis (PORP) after pancuronium or vecuronium results in hypoxemia and hypercapnia in the immediate admission period to the recovery ward. Eighty-three consecutive surgical patients received balanced or intravenous anesthesia with pancuronium for operations lasting longer than one hour or vecuronium for those lasting less than 60 min, both combined with neostigmine at the end of anesthesia. Standard clinical criteria assessed neuromuscular function intraoperatively. Postoperatively, we determined neuromuscular function (acceleromyography with supramaximal train-of-four (TOF) stimulation of the ulnar nerve, and a 5-s head lift) and pulmonary function (pulse oximetry: SpO2, and blood gas analysis: SaO2, PaCO2). We defined PORP as a TOF-ratio <70%, hypoxemia as a postoperative SpO2 > or =5% below the pre-anesthestic level together with a postoperative SaO2 <93%, and hypercapnia as a PaCO2 > or =46 mm Hg. Among the 49 pancuronium and 27 vecuronium patients studied, the PORP rates were 20% in the pancuronium group and 7% in the vecuronium group (p>0.05). Hypoxemia and hypercapnia occurred more often in pancuronium patients with PORP than in those without PORP namely 60% vs. 10% (p<0.05) and 30% vs. 8% (p>0.05), respectively. We conclude that PORP after pancuronium is a significant risk factor for hypoxemia.