[Anesthesia systems].

Abstract

A clear understanding of technical details is essential for safe handling of anesthetic machines. Following the ideas of E.A. Ernst, it is suggested that anesthesia systems be differentiated according to the underlying principles of construction into rebreathing systems, flow- and valve-controlled non-rebreathing systems, and systems without reservoirs. This classification seems much clearer than the usual differentiation into closed, semiclosed, semiopen, and open systems, which is based upon functional criteria. Anesthesia systems must be understood as technical parts (hardware) of anesthetic machines with variable function according to the chosen fresh gas flow (software). An unequivocal characterization of an anesthetic system will only be possible if its technical properties are described together with the fresh gas flow used. Most anesthetic machines currently in use are equipped with a circle system and sophisticated monitoring, which is designed for the rebreathing technique. This technique can only be used advantageously, however, if the rebreathing system is used in conjunction with substantially reduced fresh gas flows.