Objective—To evaluate bispectral index (BIS) values in pigs during anesthesia maintained with sevoflurane- fentanyl or propofol-fentanyl as a predictor of changes in hemodynamic parameters and duration of recovery from anesthesia.
Procedure—Pigs were randomly allocated to undergo 1 of 2 anesthetic regimens. Anesthesia was induced with propofol (2 mg/kg, IV); 6 pigs were administered sevoflurane via inhalation (1 minimum alveolar concentration [MAC] at a fresh gas flow rate of 3 L/min; group I), and 6 were administered propofol (11 mg/kg/h, IV; group II). All pigs received fentanyl (2.5 mg/kg, IV, q 30 min). After abdominal surgery, pigs were allowed to recover from anesthesia. Cardiovascular variables and BIS values were recorded at intervals throughout the procedure; duration of recovery from anesthesia was noted.
Results—No correlation was established between arterial blood pressure and BIS and between heart rate and BIS. Mean BIS at discontinuation of administration of the anesthetic agent was greater in group-II pigs (65.2 ± 10.6 minutes) than in group-I pigs (55.8 ± 2.9 minutes). However, recovery from anesthesia was significantly longer in group II (59.80 ± 2.52 minutes) than in group I (9.80 ± 2.35 minutes).
Conclusions and Clinical Relevance—In swine anesthetized with sevoflurane or propofol and undergoing abdominal surgery, the BIS value derived from an electroencephalogram at the end of anesthesia was not useful for predicting the speed of recovery from anesthesia. Moreover, BIS was not useful as a predictor of clinically important changes in arterial blood pressure and heart rate in those anesthetized pigs. (Am J Vet Res 2004;65:409–416)