Abstract: To compare the effect of the bispectral index (BIS) and the systolic blood pressure (SBP) on controlling the depth of propofol anesthesia. Methods: BIS (the B group) or SBP (the S group) at random was used to titrate the propofol anesthesia in 40 patients scheduled for hysterectomy. The consistency of the value of BIS and SBP to the set control value, the consumption of propofol and the emergence time were compared. Results: About (89 ±10) % of the measured BIS time points in group B, and (49±29) % in group S were maintained in the target field (50±10), (P<0.001). Significantly higher incidence of BIS levels < 40 was recorded in the group S than in the group B ［(44±31)% vs (9±10)%］ and that of BIS> 60 was recorded in the group S than in the group B［(7±16) % vs (2±2) %］ (P<0.01). Although SBP was the controlled variable in the group S, adequate hemodynamic stability (within the 15mmHg range around baseline) occurred more frequently in the group B (51±27) % in comparison with group S (34±31)%, (P< 0.05). The incidence of too low SBP, ［(41±33)% in the group B vs (64±31)% in the group S］ and the incidence of too high SBP, ［(7±11)% in the group B vs (1±2)% in the group S］ were both significantly different between the two groups (P<0.05). Recovery was quickd the consumptions of propofol were lower in the group B than those in the group S (P<0.05). Conclusion: As a controlled variable of anesthesia, BIS has more advantages in keeping the stability of anesthesia and hemodynamics than SBP.

Key words: Electromyography, The systolic blood pressure, Anesthetics, intravenous