What are the top ~10 considerations when buying an oxygen concentrator?

Database for oxygen concentrator specifications

• Supply shortages – Everyone in the world has been trying to buy these since the beginning of the pandemic. Be wary of large stockpiles of ‘available’ devices from unknown manufacturers. 
• Flow rates – Concentrators commonly produce 3, 5, 8 or 10 LPM continuous flow output, though some may produce 10 or more LPM. All devices should have an adjustable flowmeter (and if planning to use for pediatric patients, a minimum flow rate of 0.5 LPM may be needed. 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. 
  • For stable patients on stable amounts of oxygen who are using the concentrators in climate controlled rooms (e.g. COPD at home, one of the original use scenarios for portable concentrators),  a device with relatively low output < 5LPM may be sufficient 
  • For hospitalized patients who may have fluctuating needs (e.g. acute respiratory illness, COVID19), concentrators with higher outputs (e.g. 10-15 LPM, or higher) may be more desirable
• Oxygen concentration – WHO Technical Specifications stipulate output of >82% concentration of oxygen at max rated flow rate at 40 degrees C and 95% relative humidity (RH). Most high quality devices should have >90% output. NOTE: many concentrators, especially smaller (<10kg) units only produce 30% FiO2 at max flow rates, which is inadequate to care for most patients with acute respiratory illnesses.  
• Power – ensure compatibility with local power supply and outlet adapters; and ensure efficiency <70W/LPM. Many oxygen concentrators do not have backup batteries that will power the device in the event of power failure. Consider using with a voltage stabilizer and surge protector. 
• Noise – <50 dBA; many noisy units on a single ward can make it difficult to hear patient alarms
• Durability – Consider IP21 or greater to offer special protection against moisture 
• Outlet pressure – must generate at least 55kPa at all flows and ensure stable (narrow range) of output pressure (+/- 1 psi)
• Operating environment – ensure safe operation in 0 to 40 degree C, and RH 15 to 95%; ensure certified to altitude suitable for destination (many are not certified above 3000m due to partial pressure changes)
• Alarms – device must have alarms for low oxygen concentration alarm (<82%), no flow, high/low pressure, low battery, power supply failure, high temperature. NOTE: be cautious of devices with prolonged warm up periods, maximum operating durations (good units should work continuously), or auto-shutoff functions.  
• Spare parts – ensure spare parts for one year – including spare battery for power failure alarms (more recent models may use a capacitor and do not have a battery), intake filter, and internal filter
• Delivery devices – don’t forget to ensure access to delivery devices (e.g. nasal cannula, face masks and humidification bottles)
• Access to maintenance tools – ideally facilities should have pressure gauge, FiO2 meter oxygen analyzer, and spare parts for routine maintenance; consider a local service contract or identifying a provider
• Training – recipients of concentrators should be provided with training on operation, troubleshooting and maintenance
• Be wary of devices with auto-shutoff timers as these can increase likelihood for errors

Additional Resources:

• Evaluation of O2 concentrators for use in countries with limited 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
• WHO Technical Specifications for oxygen concentrators