This coaxial anesthesia circuit kit uses a tube-within-a-tube design, so only one lightweight tube runs to the patient. The inner tube carries gas in one direction and the outer limb carries it in the other, which reduces the weight and drag on the airway and keeps the working area clear. Each kit is assembled from a fixed combination of circuit length, single tube, breathing bag and connectors.
The coaxial design is the defining feature of this circuit type. Because the inspiratory and expiratory paths share a single outer tube, only one lightweight limb runs from the machine to the patient. This reduces the pull on the airway, keeps the working area clear and makes the circuit easier to manage when space around the patient is limited. Coaxial circuits are used with Mapleson D and Bain-type breathing systems.