Sevoflurane concentration available from the universal drawover vaporizer

Field anesthesia can have special considerations because of the possibly primitive conditions. The drawover vaporizer has enjoyed increased interest because of the ability to deliver an anesthetic without electricity or compressed gases. Sevoflurane is a potentially attractive field agent because of its relative insolubility in blood, giving more rapid control over anesthetic depth. We investigated the output of sevoflurane from the drawover vaporizer to determine if the concentration is in the necessary range for clinical use. We found that the output of the Ohmeda PAC drawover vaporizer delivered between 0.1 and 3.6% (v/v) sevoflurane. Therefore, the drawover vaporizer should be able to deliver a sufficient concentration of sevoflurane for anesthetic maintenance; however, this concentration appears inadequate for routine inhalation induction.