A new co-axial breathing system. A combination of the benefits of Mapleson A, D and E systems

A new, simple, versatile co-axial breathing system combining the features of Mapleson A, D and E type systems is described. The change from an A system to a D/E system is effected by a single switch and without reversal of the gas flow. Fresh gas flows in the order of 70 ml/kg/min are required for both spontaneous ventilation in the Mapleson A mode and controlled ventilation in the Mapleson D mode. The co-axial configuration offers the advantages of a single, lightweight breathing system with easy scavenging of anaesthetic gases, while the ability to switch between the A and D or E configurations offers the economic advantages of low fresh gas flows and the need for a single anaesthetic breathing system for all situations.