If I am not mistaken, the CPAP does not count against your carry on limit since it is a life sustaining medical device.
In addition, the following items can be carried on and do not count towards your baggage allowance:
Outer garments (e.g. coats, hats)
Purses up to 25cm x 30cm x 20cm (10" x 12" x 8")
Assistive devices (e.g. canes, crutches, walkers)
Containers carrying life sustaining items
Urns containing human remains