Abstract
Background
On the night before surgery, poor sleep quality due to anxiety is a frequently encountered problem.
Objective
This study aimed at determining the effect of preoperative sleep quality on intraoperative isoflurane requirements in patients undergoing elective surgeries and also offers an electroencephalography (EEG)-based classification of sleep quality.
Patients and methods
Twenty-seven adult male patients scheduled for elective open cholecystectomy with ages ranging from 20 to 40 years were included in this study. The night before the operation, the patients were subjected to an at least 8 h sleep EEG, which was scored for the following: total sleep time, percentage of slow wave sleep, and percentage of rapid eye movement sleep. Intraoperative isoflurane requirements were determined by recording the amount of inspired isoflurane concentration (every 2 min) needed to achieve an intraoperative bispectral index value between 40 and 60. Patients were classified according to sleep EEG into good sleepers and bad sleepers. Isoflurane requirements were first correlated with the EEG and then compared between the two groups.
Results
The inspired concentration of isoflurane in good sleepers was 1.15% (1.01-1.22%), whereas in bad sleepers it was significantly lower, at 0.99% (0.87-1.18%) (P = 0.003). There was a positive correlation between isoflurane requirements and both slow wave sleep percentage (r = 0.693; P = 0.003) and rapid eye movement sleep percentage (r = 0.687; P = 0.005).
Conclusion
Patients suffering from poor sleep quality on the night before surgery need less intraoperatively inspired isoflurane concentration. This finding may have clinical importance in adjusting the isoflurane dose to meet patients' requirements, avoiding intraoperative complications. In addition, an EEG-based classification of sleep is offered.