- Oxygen (O2) saturation <95% on room air by trans-cutaneous method OR need for any supplemental oxygenation (non-invasive ventilation, facemask, facetent, nasal canula, etc) or ventilator support (mechanical ventilation, bi-level positive airway pressure [BIPAP], continuous positive airway pressure [CPAP]) or increase in oxygen supplementation requirement of >=2 liters for subjects with chronic oxygen dependency. For those subjects with a history of chronic hypoxia (without supplemental oxygen), an oxygen saturation of at least 3% below the subject's historical baseline oxygen saturation.