What are the noteworthy capabilities and limitations of portable oxygen concentrators?

• Most portable oxygen concentrators use pressure swing adsorption to intake room air and output ~93-96% oxygen
• Most concentrators produce oxygen at 5 or 10LPM max, and at low pressure (this means far less than the 50psi/4bar needed to run HFNC, and most ventilators and NIPPV devices)
• There are a few portable devices capable of higher flow / high pressure output (e.g. 15-30LPM, or 50psi)
• Make sure the FiO2 is adequate (>~82-90%) at the max flow rate, as many concentrators make claims of high flows but deliver limited FiO2 (and thus limited benefit) at those flow rates. 
• Performance of concentrators may vary by manufacturer in hot and humid environments (Peel et al, Anaesthesia, 2013)
• Zeolite does not last forever – needs to be replaced around 25,000 hours, though may be considerably less depending on use, maintenance and humidity
• While they can run continuously for long periods of time (months, years) they do require routine maintenance
• When run beyond max flow (flowmeter opened all the way), this can cause premature failure due to excess moisture building up in the sieve bed

Additional Resources:

• How to setup an oxygen concentrator by wikiHow
• Preventative maintenance for O2 concentrators – Med Equipment Troubleshooting – by Engineering World Health
• Frank’s Hospital Workshop Tutorials – Oxygen Concentrators – by Frank Weithoner