EEG bispectral index monitoring in sevoflurane or propofol anaesthesia: analysis of direct costs and immediate recovery

Background: Recent studies have suggested that electroencephalogram (EEG) b ispectral index (BIS) monitoring can improve recovery after anaesthesia and save money by shortening patients' postoperative stay. We wanted to evalua te the direct costs of BIS monitoring and to measure immediate recovery aft er anaesthesia in patients with or without BIS monitoring. Methods: Eighty patients undergoing gynaecological surgery were studied. At first, 40 patients were randomized to receive either propofol or sevoflura ne anaesthesia. In these patients, BIS was collected but the information wa s not displayed. Thereafter, the anaesthesiologists were trained to follow and understand the BIS information, and 40 patients were anaesthetized with aid of the monitoring. Recovery times were measured by a study coordinator . Drug consumption was calculated. Results: BIS monitoring improved the immediate recovery after propofol anae sthesia, while no differences were seen in patients receiving sevoflurane. The consumption of both propofol and sevoflurane decreased significantly (2 9% and 40%, respectively). BIS monitoring increased direct costs in these p atients; the break-even times (704 min for propofol and 282 min for sevoflu rane) were not reached. Conclusion: BIS monitoring decreased the consumption of both propofol and s evoflurane and hastened the immediate recovery after propofol anaesthesia. Detailed cost analysis showed that the monitoring increased direct costs of anaesthesia treatment in these patients, mainly due to the price of specia l EEG electrodes used for relatively short anaesthesias.