The aim of this study is to describe the effect of the Inogen Rove 6 Portable Oxygen Concentrator on peripheral oxygen saturation in adults receiving supplemental oxygen at night and examine whether the device can adequately maintain oxygen saturation during sleep.

The study design is a prospective, single site, single arm, open label, pilot study. The aim of this study is to describe the effect of the Inogen Rove 6 Portable Oxygen Concentrator on peripheral oxygen saturation in adults receiving supplemental oxygen at night and examine whether the device can adequately maintain oxygen saturation during sleep, i.e., achieve target with initial titration setting and/or with any needed adjustments of setting.

Inclusion Criteria:

1. Subjects may be of any gender
2. Subject's age must be 40 - 80 years
3. Subjects must have a current prescription for nocturnal oxygen < 3 L/min continuous or current use of a Portable Oxygen Concentrator.

Exclusion Criteria:

1. Subject is using any ancillary medical device(s) that may interfere with the operation of or data interpretation from the InogenOne device (such as CPAP/BiPAP, NIV).
2. Subjects with nasal obstruction
3. Subjects taking any drugs that affect respiratory center drive
4. Subject has an acute illness or hospitalization within the last 30 days
5. Subject has a change in medication within the last 15 days
6. Subject is currently receiving respiratory stimulant medications (such as acetazolamide, medroxyprogesterone, doxapram, theophylline/aminophylline, protriptyline and buspirone)
7. Subject has significant comorbidities that in the opinion of the Investigator would interfere with outcomes and/or study conduct
8. Subject's prescribed treatment is in conflict with study procedures
9. Subjects with any unstable disease