Introduction: Portable oxygen devices simplify and facilitate patient therapy. This study was designed to compare oxygen saturation and patient satisfaction with a portable oxygen concentrator or with a combined system consisting of a fixed device with continuous flow oxygen dispensation and a portable device with pulse dispensation for ambulation.

Methods: This cross-over trial assessed 25 patients with COPD (92% men; mean age 72.2 ± 7.4 years; mean FEV 34.14 ± 12.51%) at four hospitals in Madrid. All patients had previously used the combined system, consisting of a fixed oxygenation system and a portable system for ambulation, with 16 (64%) using stationary and portable concentrators and 9 (36%) using a stationary reservoir and portable liquid oxygen bag. Oxygenation settings at rest and while walking were determined at baseline. Patients were maintained on the previous combined system for one week and then switched to the portable oxygen concentrator for one week. Mean SpO2 over 24 hours was calculated by the software in the oximeter, and compliance was monitored

Inclusion Criteria:

• aged 40-80 years
• had been diagnosed with COPD following the GOLD criteria
• were receiving oxygen therapy using a fixed oxygenation system and a portable system for ambulation
• without exacerbation during the previous month
• agreed to participate

Exclusion Criteria:

• terminally ill
• unable to understand Spanish
• had high oxygen flow at rest (> 3 lpm)
• high respiratory frequency at rest (> 32 rpm)
• were not achieving adequate O2 saturation levels during titration with the portable oxygen source
• had previously been diagnosed with obstructive sleep apnea hypopnea syndrome (SAHS)
• were receiving mechanical ventilation.