3. Arterial oxygen saturation <95% on room air by trans-cutaneous method, or need for any supplemental oxygenation or ventilatory support [mechanical ventilation, bi-level positive airway pressure (bipap), continuous positive airway pressure (cpap)], or increase in oxygen supplementation requirement of >=2 litres for subjects with chronic oxygen dependency. For those subjects with a history of chronic hypoxia (without supplemental oxygen), an arterial oxygen saturation of at least 3% below the patient's historical baseline oxygen saturation will satisfy this criterion OR