Figure 6. With cessation of administration of sevoflurane and conversion to a nonrebreathing system, the inspired concentration of sevoflurane (A) and compound A (B) decreased immediately to zero. The end-tidal concentrations also decreased rapidly. For sevoflurane, the decrease followed the expected exponential decay, but did not for compound A. Instead, the compound A concentration decreased to a constant level, equaling approximately 10% of the value at the end of sevoflurane administration.