CIRCLE ABSORBER

Typical Number in Hospital: 20

Cost Bands: 2

References: 2

During anaesthesia, the expired gases still contain some of the anaesthetic agent, and this may be rebreathed if the carbon dioxide is removed in an absorber. This is efficient in the use of anaesthetic gases, reduces pollution of the room, and raises the humidity of the inspired (rebreathed) gas.

The most commonly used rebreathing circuit is the circle closed circuit in which gases are steered round a circle of breathing tube into which is fitted a patient connection, a rebreathing bag, fresh gas inlet, and a circle absorber, including non-return valves. The absorber has a chamber full of soda-lime granules, a one-way valve and a switch to bypass the chamber. Variations on this arrangement may include two chambers for inclusion at different points in the circle, or to alternate the use of the chambers so that spent soda-lime can be bypassed in favour of a second canister. When using low flows it is essential that the circuit should be leak proof.