Patient-maintained remifentanil target-controlled infusion for the transition to early postoperative analgesia

We studied 30 male patients in the early postoperative period to assess the efficacy, safety and feasibility of a patient-demand, target-controlled infusion (TCI) of remifentanil. All patients received the same TCI-based propofol-remifentanil anaesthetic for elective orthopaedic surgery. At the end of surgery, infusion of remifentanil was reduced progressively until patients were breathing spontaneously. After extubation and transfer to the post-anaesthesia care unit, patients were given control of a hand-set and were able to increase the target remifentanil blood concentration by increments of 0.2 ng ml-1. If there were no demands, the TCI controller automatically reduced the target concentration. Pain scores, sedation level, ventilatory frequency, oxygen saturation and nausea were assessed. Mean time to onset of satisfactory analgesia (VAS < or = 3, out of 10) was 18.9 (95% confidence interval (Cl) 15.8-21.9) min at a mean target remifentanil concentration of 2.02 (Cl 1.87-2.16) ng ml-1. There were no episodes of hypoxaemia and the lowest ventilatory frequency was 9 bpm. Nausea occurred in 26.6% of patients and 10% vomited. The majority of patients were only slightly sedated. These results imply an effective tool without respiratory side effects in the early postoperative period after anaesthesia using remifentanil as the analgesic component.