Figure 1. Inspired and end-tidal sevoflurane concentrations measured at 30-sec intervals during mask administration of sevoflurane from a Penlon model PPV Sigma vaporizer. The data represent the average (plus/minus SEM) of the measurements from all three treatment groups. Time 0 = the first reading on placement of the face mask. The vaporizer dial was set to the maximum throughout the exposure period (7%), and the fresh gas flow (FGF) was 6 L/min for the first 3 min and 3 L/min thereafter.