The Effect of Butorphanol on the Bispectral Index during Intravenous Anesthesia with Propofol and Remifentanil

ABSTRACT

BACKGROUND: The aim of this study was to investigate the effect of butorphanol on the Bispectral Index (BIS) during the administration of intravenous anesthesia with propofol and remifentanil. METHODS: Forty adult patients, ASA I-II, scheduled for an emergency laparoscopic appendectomy were studied. The doses for the anesthetics were adjusted to keep the BIS value between 40 and 50. After 20 minutes of stable anesthesia, the subjects were randomly allocated to receive intravenous saline (control group) or 0.02 mg/kg butorphanol (butorphanol group). The BIS values, mean arterial pressure, and heart ratewere recorded every five minutes for a period of 20 minutes. RESULTS: The mean BIS values after butorphanol administration were not significantly different from the values following the administration of saline, throughout the observation period. No patients were able to recall explicitly any events under anesthesia. No significant changes in mean arterial pressure and heart rate were noted after butorphanol administration. CONCLUSIONS: Butorphanol given to prevent postoperative pain does not modify the BIS value during anesthesia maintained with remifentanil and propofol.