[Postoperative pulmonary function after lung surgery. Total intravenous anesthesia with propofol in comparison to balanced anesthesia with isoflurane].

After lung resection, early extubation and the rapid return of the patients ability to cooperate is the predominant goal. Propofol anaesthesia is characterised by rapid awakening and recovery of cognitive and psychomotor functions and is consequently desirable for such operations. Experience so far in lung surgery, however, is limited. Besides the level of consciousness we investigated various spirometric parameters after lung resection. Total intravenous anaesthesia was performed with propofol, while balanced anaesthesia was performed with isoflurane. METHODS. A total of 93 patients evaluated electively for wedge excision or lobectomy were enrolled in an open, prospective, randomised, interindividual comparative study. Sixty-three patients could be evaluated with complete data sets. In the evening and the morning before the operation the patients were premedicated orally with clorazepate 0.5-0.7 mg/kg. Anaesthesia was induced in group 1 with propofol (1.0-2.5 mg/kg) and maintained with propofol (4-12 mg/kg) in 50% O2/air. The patients in group 2 received methohexital (1-2 mg/kg) for induction and isoflurane (0.4-2.0 vol%) in 50% O2/air for the maintenance of general anaesthesia. In both groups analgesia was achieved by using fentanyl (up to 10 micrograms/kg) and muscle relaxation by using atracurium. Psychomotor tests (minimal mental state, reaction time) were performed the day before the operation (t1), immediately prior to induction of anaesthesia (t2) and 5 min, 30 min, 60 min, 90 min, 24 h, and 7 days after extubation (t3-t8). Spirometry (forced expiratory volume in 1 s, FEV1; forced vital capacity, FVC; peak expiratory flow, PEF) was carried out at times t1, t2 and t5-t8. RESULTS. The two groups were comparable regarding preoperative status (age, sex, preoperative risk score, psychomotor tests, and spirometric values) and the operation performed (wedge excision/lobectomy, duration of anaesthesia). The extubation time was slightly shorter in the propofol group (18 +/- 8 min) than in the isoflurane group (20 +/- 6 min). Also, the results of the psychomotor tests were somewhat better in the propofol group than those in the isoflurane group. The clearest differences were found in the early postoperative period, but not all differences were significant. Statistically highly significant differences between the two groups were found for the three spirometric parameters. Based on the FEV1 value of the 7th postoperative day, FEV1 taken 60 min after extubation declined by 27.9% in the propofol group vs. 51.7% in the isoflurane group (P = 0.01). At 90 min after extubation the corresponding decline in the propofol group was 26.6%, in the isoflurane group 51.1% (P = 0.003). In addition, the decline of FVC and PEF measured 60 min and 90 min after extubation was significantly smaller in the propofol group than in the isoflurane group. CONCLUSION. The postoperative impairment of lung function after lung resection under propofol anaesthesia is statistically significantly smaller than under isoflurane anaesthesia. Total intravenous anaesthesia with propofol is particularly suitable for this kind of operation.