Evaluate subjects in an prospective observational study in which subjects will be screened and administered scientifically validated questionnaires at study entry and during the observation period at specified intervals to determine the affect of the Portable Oxygen Concentrator on improvements in exercise capability, dyspnea and quality of life as primary endpoints, utilizing the Baseline Dyspnea Index (BDI), Transitional Dyspnea Index (TDI), the Chronic Respiratory Disease Questionnaire (CRQ) and six minute walk test (6MWT). The secondary endpoints will be rate of exacerbations, sleep quality (reported as number of hours sleep improvement; utilize Epworth Sleepiness Scale \[ESS\]), and health care utilization (emergency room encounters, hospital admissions).
