Figure 4

Summary of propofol concentrations during different phases of propofol anesthesia and BIS values over time. (A) represents the means (black solid circles for induction phase, squares for maintenance and inverted triangles for emergence phase) and standard deviations (SD) (black vertical lines) of propofol concentrations during different phases of anesthesia; The propofol concentration during the induction phase (first 15 minutes) was 7.0 ± 4.1 mg.l^-1 (n = 16). The mean (SD)(number of samples) for propofol concentrations collected during 15-30, 30-60, 60-90, 90-120 and >120 minute time intervals of maintenance anesthesia were 6.8(1.8)(26), 6.9(2.5)(41), 5.8(2.2)(36), 5.4(2.7)(15) and 6.1(3.2)(29) mg.l^-1 respectively. (B) shows the means (black solid circles) and SD (black vertical lines) of blinded BIS values during 10-200 minutes of maintenance phase of propofol anesthesia. Grey shaded areas depict range of propofol concentrations reported to be associated with BIS 50 in children (A) (3.2-5.4 mg.l-1: Riguozzo et. al, 2010) and BIS values generally considered to infer adequate depth of anesthesia (B) (46-60) for this population.