A randomised cross-over clinical testing of portable oxygen concentrators in patients with COPD

Portable oxygen concentrators (POC) deliver oxygen via intermittent demand valves (IDV). these merit comparison with standard continuous flow oxygen (CFO). We have performed a multicenter comparison of 4 POC in a cross over study in 74 patients with COPD (age = 67±10; FEV1 = 41±20% predicted). Each patient tested one of 4 POC at rest and during a six minute walk test (6MW), with oxygen saturation recording (SpO2). Noise and discomfort were evaluated by visual analogue scales (VAS). Results: Mean 6MW distance was 308m ±114 with POC and 315 m ±111 with CFO (p>0,06). However the distance walked with POC was clinically significantly less (by >10%) than CFO in 23% of patients and significantly better than CFO (by >10%) in 13,5% of patients. Dyspnoea during 6MW by VAS was identical for both types of device. 55,5% of patients had SpO2 fall with both devices and 27% no fall in SpO2. 13,5% had SpO2 fall with POC alone and 4% with CFO alone. Overall patients appreciate the POC because of security of oxygen supply. However, they judged POC oxygen delivery significantly less amenable and noisier than CFO. Conclusion: 4 POC devices with demand valve oxygen delivery had similar efficacy to CFO devices but were noisier and less comfortable. Prescription of such devices needs to be individualized as regards settings for O2 delivery and patient comfort and lifestyle.