Closed circle systems. A new direction in the practice of anesthesia.

On the basis of the near-constant uptake of inhalation anesthetics at the alveolar membrane, the large closed-circuit volume which acts as a buffer, and the effect of concentration on uptake, we have evolved a simple and practical technique of closed-circuit anesthesia. After initial high flow wash-in of anesthetic gases into the FRC, a nearly constant slow fresh-gas flow can be maintained.