An enclosed efferent afferent reservoir system: the Maxima.

A single, lightweight, valveless, non-absorber breathing system, which functions with near maximal efficiency (hence the name Maxima) in spontaneous and controlled ventilation is described. It may be classified as an enclosed efferent afferent reservoir (EEAR) breathing system and is characterised by the selective elimination of alveolar gas in all modes of ventilation. A functional description explains how this is achieved in the system in spontaneous and controlled ventilation. The potential for error which arises in combination systems for different switch positions with different modes of ventilation is avoided, as it is a single universal system. With no moving parts, mechanical reliability is guaranteed. The apparatus deadspace is negligible making the system usable even in neonates. Finally, the characteristics of the theoretical ideal non-absorber circuit are discussed as this illustrates the objective of the circuit design and important physical principles surrounding its function.