REMIFENTANIL WITH PROPOFOL OR ISOFLURANE - A COMPARISON OF RECOVERY TIMES AFTER ARTHROSCOPIC SURGERY

Objectives: Due to its unique pharmacokinetics, the new esterase-metab olised opioid remifentanil results in rapid post-anaesthesia recovery. The aim of this clinical investigation was to compare recovery times after remifentanil anaesthesia in combination with hypnotic concentrat ions of either propofol or isoflurane. Dosages used in the study proto col were based on recommendations by the pharmaceutical manufacturer. Methods: Patients (ASA status I-II) scheduled for elective arthroscopy were included in this trial. Without premedication in the morning, an aesthesia was induced identically in both groups: remifentanil bolus ( 1 mu g/kg), start of remifentanil-infusion (0.5 mu g/kg/min), followed immediately by propofol (ca.2 mg/kg). For maintenance of anaesthesia remifentanil (0.25 mu g/kg/min) was combined with either a propofol in fusion of 0.1 mg/kg/min or 0.5 MAC isoflurane (=0.6 vol.%) in O-2/air. Anaesthetic delivery was discontinued simultaneously with termination of surgery and recovery times were recorded. Results: A total of 40 p atients were studied at random in two groups of 20 each with comparabl e demographic data and anaesthetic technique (Tables 1 and 2). In both groups emergence was very rapid. Recovery times were significantly sh orter for remifentanil-isoflurane than for remifentanil-propofol (Tabl e 3): spontaneous ventilation 5.1 vs 8.1 min (P<0.05), extubation 5.5 vs. 8.6 min (P<0.02), post-anaesthesia recovery score greater than or equal to 9 of 10 points 6.2 vs 11.3 min (P<0.01), and arrival at PACU 16.2 vs 19.2 min (P<0.01). Mild to moderate shivering was noted in 40% of all patients (9 cases following isoflurane, 7 following propofol). Conclusions: Using the manufacturer's recommended dosages, emergence after remifentanil anaesthesia is more rapid with 0.5 MAC isoflurane t han with 0.1 mg/kg/min propofol. These results are most probably due t o the different pharmacological properties of both co-anaesthetics, es pecially the applied dosages, and to different interactions with remif entanil. Present clinical experience suggests that a further dose redu ction, especially for propofol, is possible. For both remifentanil gro ups emergence was remarkably rapid between return of consciousness and the awake state (on-off phenomenon), which might contribute to post a naesthesia safety.