Comparison of: (a) average inhaled anesthetic dose per breath; (b) end-inspiratory anesthetic concentration; and (c) end-expiratory anesthetic concentration measured during targeted and continuous delivery. Data are shown for sevoflurane (left bars) and isoflurane (right bars). Data are averaged across animals, with error bars denoting SD. *Significantly greater compared to targeted sevoflurane or isoflurane delivery at both 10 and 20 min, P < 0.05.