Low Flow Anesthesia in Children Undergoing Strabismus Surgery

Low-flow anaesthesia is generally adminstered as nitrogen wash-out, a period of higher flow rate in combination with a high vaporizer setting for initial saturation, and subsequent reduction of fresh gas flow and adjustment of the vaporizer to maintain the desired end-tidal anesthetic agent concentration (Etaa).In the initial wash-in phase, the vaporizer setting is adjusted to 6% for desflurane and 2.5-3% for sevoflurane, with FGF=4 L/min, until the Etaa concentration is 1-1.3 MAC. In another method, the vaporizer setting is adjusted to 12-18% for desflurane and 6-8% for sevoflurane, with FGA=1 L/min. Reducing the FGF during the wash-in period prevents unnecessary depth of anesthesia and reduces the consumption of inhalational anesthetics. In LFA using minimal FGF (250-500 mL/min), if the vaporizer is turned off 10-15 min before the end of the operation and the FGF is not changed, the inhaled anesthetic agent concentration gradually and slowly decreases to zero.