Cast air delivery systems, cast ventilation sleeves and methods of manufacturing cast sleeves are disclosed herein. In one embodiment, a method of manufacturing cast ventilation sleeves includes forming an elongated cylindrical sleeve from a breathable, elastomeric material. The method can further include providing an air delivery tube configured to receive pressurized air. The method can also include disposing a plurality of spaced apart holes in the air delivery tube, wherein the holes can be positioned to disperse the pressurized air along a tube length. Additionally the method can include coupling the air delivery tube to the elongated sleeve to form a cast ventilation sleeve stock. The air delivery tube can be positioned to be generally parallel to a sleeve length and the tube length can be generally equal to a sleeve length. The elongated sleeve can be cut to a selectable length for use under an orthopedic cast.