Comparison of Enflurane Consumptions and Costs in Low Flow and High Flow Anesthesia

Lee, Jong Kook; Um, Sang Yong; Chung, Chan Jong; Chin, Young Jhoon

Abstract

BACKGROUND: The amount and composition of fresh gas flow affect the consumption of inhalational anesthetics. The purpose of this study was to compare the enflurane consumption and economic aspects of low flow and high flow anesthesia.
METHODS
Thirty patients, ASA physical status I or II, aged 20 65 yr., scheduled for gastrectomy under inhalational anesthesia, were studied. The patients were randomly assigned to one of three groups according to the fresh gas flow: O2 500 ml/min (group I); N2O 2 L/min - O2 1 L/min (group II); O2 3 L/min (group III). Anesthesia was maintained in group I by a continuous infusion of liquid enflurane into the inspiratory limb of the breathing circuit, using a syringe pump. In groups II and III, enflurane was administered by a conventional vaporizer. The cumulative dose of liquid enflurane was measured every 10 min during anesthesia. Hemodynamic parameters, inspired and expired enflurane concentrations, and enflurane consumptions were measured.
RESULTS
There were no significant differences among the three groups in hemodynamic changes. The enflurane consumption was significantly less in group I than in groups II and III over time (P < 0.05).
CONCLUSIONS
Low flow anesthesia offers economic advantages over high flow anesthesia.