A double-blind study of the respiratory effects of nalbuphine hydrochloride in spontaneously breathing anesthetized patients.

Nalbuphine hydrochloride 0.2 mg/kg was compared with meperidine 0.5 mg/kg in a double-blind study in 20 patients undergoing elective inguinal hernia repair while breathing spontaneously under general anesthesia. The respiratory effects of the two drugs studied were continuously and accurately recorded with a wet wedge spirometer throughout the procedure. The acute respiratory effects of these analgesic drugs could therefore be assessed. The measurements recorded before any surgical stimulation showed that both nalbuphine and meperidine produce a similar degree of respiratory depression. These results are at variance with earlier studies that drew conclusions from measurements that were neither continuous nor accurate. Nalbuphine was found to be a satisfactory analgesic adjuvant in this anesthetic technique.