Recurrent respiratory depression after low doses of alfentanil

Abstract

A case of recurrent respiratory depression after the administration of alfentanil to a 45-year-old woman undergoing partial gastrectomy has been reported [1]. This phenomenon is well known with fentanyl and sufentanyl, but very few cases have been published with alfentanil [2,3]. We describe the case of a 35-year-old man, weighing 80 kg, classified ASA 1 and scheduled for vitreoretinal surgery on his right eye. Hydroxyzine (2 mg kg−1) was given orally 2 h before surgery. General anaesthesia was induced with propofol (3 mg kg−1), rocuronium (0.5 mg kg−1) and alfentanil (0.0125 mg kg−1). After tracheal intubation, anaesthesia was begun with inhalation of isoflurane (2 MAC) and three additional increments of alfentanil at 30 min (0.018 mg kg−1), 60 min (0.0093 mg kg−1 and 120 min (0.00625 mg kg−1) respectively, giving a total dose of 0.046 mg kg−1 over a 2 h 30 min period. In the recovery room, the patient's pulse oxygen saturation decreased several times. Nevertheless, verbal stimulation was sufficient to increase the pulse oxygen haemoglobin towards the normal saturation range. After extubation, the pulse saturation was 98%, after which no nasal oxygen was added. The falls in the values occurred at 30 min (85%), 100 min (84%) and 180 min (89%) after extubation, i.e. at 70 min, 140 min and 220 min after the last injection of alfentanil. We realize that the last fall in saturation value was moderate but occurred a long time after the last injection of alfentanil (220 min). No hepatic or renal disease was identified, but cytrochrome P450 was not assessed. The consequences are that patients who have received one or more injections of alfentanil must have their pulse oxygen saturation measured carefully during the post-operative period in a recovery room after the injection of alfentanil. E. CALENDA M. MURAINE Département d'Anesthesie Réanimation and Service d'Ophtalmologie, Centre Hospitalier Universitaire de Rouen, 1 rue de Germont 76031 Rouen Cedex, France