MAGILL ATTACHMENT

Typical Number in Hospital:

Cost Bands:

References: 2

Alternatively called the Mapleson 'A' breathing circuit, this is the most commonly used of all breathing circuits for anaesthesia. It consists of a reservoir bag (not a rebreathing bag since exhaled gases should never reach it), a corrugated breathing tube, an expiratory valve, and a connection for a facepiece or endotracheal tube. Fresh gas is supplied at or slightly below the patient's minute volume through a feed at the bag end. When the patient exhales, most of the gases pass out through the expiratory valve, and so very little is rebreathed.

As a semi-closed breathing system it is satisfactory for spontaneous ventilation but the expiratory valve limits the pressure which can be applied during positive pressure ventilation. Increasing the blow-off pressure to prevent this is unsatisfactory.