Peroperative nitrous oxide does not influence recovery after laparoscopic cholecystectomy

We have evaluated the effects of nitrous oxide on recovery following laparoscopic cholecystectomy in a prospective, randomised, double-blind study with 42 otherwise healthy patients. All patients received meperidine 1 mg/kg and atropine 6 micrograms/kg im for premedication, and anaesthesia was induced with fentanyl 2 micrograms/kg and thiopental 4-6 mg/kg. Succinylcholine was used for the intubation and muscle relaxation was achieved using vecuronium. Isoflurane with 70% nitrous oxide in oxygen and fentanyl was used for maintenance of anaesthesia in group I (n = 19), and isoflurane in air/oxygen and fentanyl in group II (n = 23). The postoperative ward staff and the surgeon evaluating the postoperative recovery were blinded to the anaesthetic technique. No differences were found in duration of operation and anaesthesia, need for postoperative analgesia or postoperative nausea treated medically. Recovery, judged by the Steward Coma Score, comprehension and collaboration, degree of sedation and orientation in time and space, was similar in the two groups. Postoperative hospital stay was 1 (1-4) day in the nitrous oxide group (median (10-90th percentiles) versus 2 (1-4) days in the air group. The time until patients were recovered, as judged by return to work and normal daily activities, was the same in the two groups: 8 (4-11) days in the nitrous oxide group and 8 (4-11) days in the air group. We conclude that nitrous oxide has no influence on recovery after laparoscopic cholecystectomy.