POSTTHORACOTOMY PULMONARY-FUNCTION - A COMPARISON OF EPIDURAL VERSUS INTRAVENOUS MEPERIDINE INFUSIONS

It has remained unclear whether epidural opioid analgesia permits bett er recovery of postthoracotomy pulmonary function than an optimal meth od of systemic opioid administration. Lumbar epidural meperidine infus ions were compared with intravenous patient controlled analgesic (PCA) meperidine infusions in a prospective randomized unblinded study for 72 hours postthoracotomy. Before induction of general anesthesia, pati ents received a bolus of meperidine, 1 mg/kg, and an infusion of meper idine, 0.33 mg/kg/hr, was started via either a lumbar epidural or intr avenous catheter. Postoperatively, the meperidine infusion rates were titrated as needed for analgesia. In addition, the intravenous group r eceived meperidine, 10 mg per dose, as required, from a patient-contro lled analgesia pump. No other opioid was administered during the study period. Patients were studied for recovery of spirometric tests of pu lmonary function, visual analog pain scores, sedation, arterial blood gases, meperidine dose requirements, radiographic pulmonary com plicat ions, and neurologic signs and symptoms. A subgroup of 10 patients (5 from each group) had venous blood samples drawn every 24 hours for 96 hours and assayed for serum meperidine and normeperidine concentration s. Epidural meperidine analgesia was associated with improved postthor acotomy pulmonary function, better analgesia scores, and lower meperid ine dose requirements than intravenous PCA meperidine. There were no d ifferences between the epidural versus intravenous PCA subgroups with respect to serum meperidine or normeperidine levels. Normeperidine lev els greater than 300 ng/mL were associated with an increased incidence of shakiness and/or tremors. Meperidine provides satisfactory posttho racotomy analgesia via a lumbar epidural infusion. This analgesia is a ssociated with improved recovery of postoperative pulmonary function w hen compared with an intravenous PCA meperidine infusion. Copyright 19 95 by W.B. Saunders Company