Mapleson anesthesia breathing circuits

This graphic shows the five Mapleson breathing circuits as originally designated, as well as the Jackson Rees modification (Mapleson F). The circuits differ with respect to the placement of the inlet for fresh gas, and the APL valve and breathing bag if present. Mapleson E does not allow for positive pressure ventilation by hand, as it does not include a breathing bag. The breathing bag in Mapleson F has an open end and can be used for positive pressure ventilation by hand by occluding the end of the bag or adding an adjustable valve to the end of the bag.

Use of these breathing circuits during general anesthesia has largely been replaced by use of standard anesthesia machine breathing circuits. Mapleson circuits are occasionally used in specific circumstances (eg, for patient transport, during sedation).