RESERVOIR BAG

Typical Number in Hospital: 300

Cost Bands: 1

References: 2

This is a rubber bag used during gas anaesthesia to store fresh gases supplied from the continuous flow anaesthetic machine during the expiratory phase, and to deliver this gas (or part of it) during inspiration. It is physically identical to a rebreathing bag, and a normal adult bag has a 2 litre capacity. It may be used to assist ventilation of the patient's lungs by squeezing it during inspiration. Normally the bag is soft and floppy so that it does not apply significant pressure to the lungs. A stiffer bag may be used with some ventilators on which the bag plays a part in the action (e.g. Autovent). Some ventilators may require a special pressure-limiting bag from which gas is automatically vented when it fills beyond a certain amount. Should the bag overfill, the elasticity of the bag itself will limit the final pressure.

Reservoir bags are normally single ended (e.g. for attachment to the bag mount on the anaesthetic machine) but can be double ended such as for use in the Rees T-piece paediatric circuit. In this case ventilation is assisted by squeezing the bag while sealing the bag outlet tube with a finger, and then releasing this for the rest of the breathing cycle.