Abstract: An improved cardiopulmonary resuscitation device for resuscitating human infants is provided. The device includes a manually compressible and resiliently expandable bag constructed of an elastomer shell that encloses a breathable gas chamber having a volume capacity sufficient to inflate the lungs of a human patient when the bag is fully compressed. The shell includes at least one compressible region constructed of a wall having less resilience than the shell's average resilience. The less resilient region helps prevent over inflation of the patient's lungs. The device further includes a patient interface assembly that is communicable with a breathable gas outlet of the bag breathable gas chamber, and a breathable gas source communicable with an inlet of the bag breathable gas chamber. The device can optionally include a breathable gas manometer to monitor backpressure from the patient's lungs to further insure against over inflating the patient's lungs.