A simple apparatus for accelerating recovery from inhaled volatile anesthetics

Hyperpnea increases anesthetic elimination but is difficult to implement wi th current anesthetic circuits without decreasing arterial PCO2. To circumv ent this, we modified a standard resuscitation bag to maintain isocapnia du ring hyperpnea without rebreathing by passively matching inspired PCO2 to m inute ventilation. We evaluated the feasibility of using this apparatus to accelerate recovery from anesthesia in a pilot study in four isoflurane-ane sthetized dogs. The apparatus was easy to use, and all dogs tolerated being ventilated with it. Under our experimental conditions, isocapnic hyperpnea reduced the time to extubation by 62%, from an average of 17.5 to 6.6 min (P = 0.012), but not time from extubation to standing unaided. This apparat us may provide a practical means of applying isocapnic hyperpnea to shorten recovery time from volatile anesthetics.