Figure 1. Heart rate (mean +/- SD) was measured before induction of anesthesia (baseline), at the time of loss of the eyelash reflex, and at the time of return of conjugate gaze in the three treatment groups: sevoflurane in 100% oxygen, sevoflurane in 66% nitrous oxide, and halothane in 66% nitrous oxide. Compared with the baseline value, heart rate increased only at the time of return of conjugate gaze in the sevoflurane - oxygen group (*P < 0.01).