Contemporary portable oxygen concentrators and diverse breathing behaviours -- a bench comparison

BACKGROUND: Decades of clinical research into pulsed oxygen delivery has shown variable efficacy between users, and across a user’s behaviours (sleep, rest, activity). Modern portable oxygen concentrators (POCs) have been shown as effective as other oxygen delivery devices in many circumstances. However, there are concerns that they are not effective during sleep when the breathing is shallow, and at very high respiratory rates as during physical exertion. It can be challenging to examine the determinants of POC efficacy clinically due to the heterogeneity of lung function within oxygen users, the diversity of user behaviour, and measurement issues. Representative bench testing may help identify key determinants of pulsed-oxygen device efficacy. METHODS: Three contemporary devices were bench-evaluated across three simulated breathing behaviours: activity, rest, & oronasal breathing during sleep. Emphasis was placed on breathing patterns representative of oxygen users. RESULTS: All three POCs performed well during simulated breathing during exertion and at rest. Differences in triggering ability were noted for the scenario of oronasal breathing during sleep. CONCLUSIONS: The results are supportive of contemporary POC triggering abilities. The differences shown in ultimate trigger sensitivity may have relevance to oronasal breathing during sleep or other challenging scenarios for pulsed oxygen delivery, such as dominant mouth breathing during exertion or unfavourable nasal geometry.