A combination positive airway pressure (PAP) or continuous positive airway pressure (CPAP) and resuscitation system and related methods. The systems can be well-suited for use in providing CPAP therapy for a neonate or infant patient, with the ability to also provide resuscitation therapy at a peak inspiratory pressure (PIP) as needed or desired without switching to another system or switching the patient interface. The system can include an expiratory pressure device capable of regulating a positive end expiration pressure (PEEP) of the system, which preferably can also induce pressure oscillations relative to a mean PEEP.
