Cluster 202: oxygen saturation pulse oximetry rest resting hypoxemia baseline pao arterial Cluster 421: air saturation room oxygen baseline desaturation ambulatory rest function pulmonary Cluster 1110: room air perform forced predicted capacity pulmonary oximetry fvc pulse Cluster 1730: pulse room air oximetry oxygen saturation pulmonary dyspnea reserve level Cluster 1952: oximetry pulse room air infusion inclusion patients treatment previously radiation