The Oxygen Concentrator Directory

Sharp inequities regarding medical oxygen access were highlighted during the COVID-19 pandemic which led to an increase in momentum from donors and global actors to make oxygen more accessible.

Despite a lot of emphasis on larger scale sources (oxygen generator plants, liquid oxygen solutions), oxygen concentrators have a particularly important role in low resource settings, namely for smaller and/or more remote health facilities, and for both acute and non-critical-care patients. This is particularly so in many low- and middle-income countries (LMICs), where access to large scale sources of oxygen is often unavailable, or at best, limited.  

With many different oxygen concentrator makes and models available, there remained a gap in evidence regarding product performance, safety, usability, repairability, electrical resilience and energy efficiency to inform decision-making prior to investment. These factors are of particular importance when using oxygen concentrators in challenging environments often found in low- and middle-income countries (LMICS), such as those with high heat and humidity, electricity volatility, or where there is a lot of dust. 

The Oxygen CoLab, a UK Foreign, Commonwealth & Development Office-funded initiative, has undertaken comprehensive lab testing into 11 models of oxygen concentrators. The primary goal of this research is to provide the transparency needed to inform investment decisions in LMICs. Working with LabTest Certification and ECRI, this testing replicates real-world performance scenarios to evaluate how concentrators perform under varying conditions.

The target audience for these lab testing results are any stakeholder along the medical oxygen supply chain who will have interest in the performance, quality, and safety of oxygen concentrators. The following profile categories have potential involvement with oxygen concentrators, including but not limited to, policy, planning, procurement, use, maintenance and repair:

• Ministry of Health

• National Regulatory Agency/Authority and National Standards Institutes 

• National associations or national councils 

• NGOs, multilaterals, and donors 

• Suppliers and distributors 

• Human resources for health:

  • Medical personnel

  • Technical personnel

  • Administrative personnel

Tests, examinations or observation protocols were applied to the oxygen concentrators for each of the following evaluation criteria: performance, safety, usability, repairability, electrical resilience and energy efficiency. Targets for evaluation criteria features and functionality were derived from ‘Global Public Good’ specifications (WHO 2020 and WHO-UNICEF 2019) and the UNICEF TPP for required and preferred features respectively. An overview of outcomes, alongside an interpretation, are presented above.

Performance

Performance testing served to mimic varying environmental conditions under which the devices could be expected to perform as expected. The focus of performance testing was on exposure to heat (20-40˚C / 68-104˚F), relative humidity (50-95%) and prolonged dust exposure. This included operations under various scenarios, including the simultaneous application of heat and humidity and intermittent use to reflect both planned and unplanned shutdown.

Safety

The safe function and safety features of oxygen concentrators were observed, either under various operating conditions or presence of features whose purpose was for the safety of the user and the patient. 

Usability

Though an established technology, historic use-case has been in the homecare setting, the units evaluated were examined and observed for usability in a clinical care setting, both in terms of the concentrators’ functions as well as features such as mobility with consideration given to variability between different makes and models of oxygen concentrators.

Repairability

Oxygen concentrators require routine maintenance and repair. Personnel responsible for doing so are typically tasked with managing maintenance and repair of all devices in a health facility, many of which have several makes and models. As time and difficulty for repair increase, the chance that they will be repaired, and effectively so, decreases.

This category focuses on time and ease to disassemble and inspect medical oxygen concentrators, examining the complexity of the assembly (total number of components, positioning, ease of access, etc.), and to perform a series of standard preventive maintenance tasks to shed light on the relative time and ease with which to do so.

Electrical resilience

This category focused on an oxygen concentrator’s ability to perform under various power-related anomalies such as voltage surges (transient power spikes), and continuous low or high voltage conditions.

Energy efficiency

With ever-present scarcity of continuous reliable power supply in many LMICs, particularly in remote geographies, and electricity still having high costs, energy efficient features on oxygen concentrators are preferred. This was hence considered in the testing.

Cost

Cost of these units represents the costs paid by the CoLab for this research.

Criteria for selecting oxygen concentrators to undergo testing were to:

• Have an upper flow rate of 10 L/min.

• Be marketed (available for purchase) worldwide.

• Have valid and current regulatory approval/clearance as medical devices at the time of assessment from a well-regulated market such as (but not limited to): United States regulations (US FDA), European Union regulations (CE marking).*

*One of the tested concentrators, the PulmO2, had not obtained valid and current regulatory approval when testing, but it has now obtained approvals. The concentrator was included despite this as it was decided that there would be significant public interest in the product’s performance.

The following products were included for testing, examination and observation (listed in alphabetical order by brand):

• Caire: Newlife Intensity 10

• Canta: V10-W-NS

• DeVilbiss: 1025KS

• Drive DeVilbiss and Sanrai: PulmO2

• Jumao: JM 10A Ni

• Konsung: KSOC-10

• Longfian: Jay-10

• Nidek: Nuvo 10 model 1005

• Olive: OLV-10S

• SysMed: OC-S100/OT Elite 10

• YuWell: 7F-10

To find out the specifics of how we tested these devices against our assessment criteria, please download the full research protocols here:

• Dust

• Electrical Resilience

• Energy Efficiency

• Performance (Heat and Humidity)

  • 24 hour baseline

  • High and low temperature

  • High temperature and humidity (on and off cycling)

  • High temperature and humidity (unplanned shutdown)

  • Low and high temperature and excess flow

  • Water backflow

• Repairability

• Safety

• Usability

The following details requirements or preferences under each evaluation criteria:

Performance
An environmental chamber was used to control various scenarios combining heat and humidity conditions, and a dust chamber was used to observe concentrator performance over prolonged exposure to dust conditions according to MIL-STD-810G environmental engineering standard.

The following were considered as acceptable findings:

• Oxygen concentration must be ≥ 82%, though preferably ≥ 90%, over the entire range of flow settings and within 5 minutes from the start of the test.

• Flow must be accurate; device flowmeter to match external test.

• Output pressure must be > 55 kPa (8 psi), though preferred to be > 137 kPa (20 psi).

• Devices must continue to operate and deliver the rated oxygen concentration even after lengthy operation in environments up to 40°C and 50-95% relative humidity, including with an unpredictable and highly variable duty cycle.

• Devices must continue to operate after lengthy exposure to dust (significantly reduced flow and/or oxygen concentration is acceptable).

• Unit air intake should not be located at the bottom of the device, and must have a gross particle filter (also called: cabinet filter, air intake filter, coarse filter) and compressor intake filter (also called: inlet filter, intake filter, feed filter).

• Mechanisms or design elements to support operations in hot and humid environments or to prevent dust from reaching the compressor filter and subsequent components were deemed preferable.

Safety
The following were considered as acceptable:

• Oxygen concentration and flow rate should be stable (i.e., meet minimum required concentration over period of use).

• Devices should measure and display the delivered oxygen concentration in real time. This can be displayed by an indicator (e.g., green LED), and should always be visible when the device is running (i.e., affirmative indication that concentration is ≥ 82%).

• Devices should alarm if the concentration falls below 82%, if the flow of oxygen is occluded, or if the device loses power.

• Features that restrict or discourage overdraw (i.e., providing more than the rated flow, thus diluting the oxygen concentration of the gas delivered to the patient) are preferred.

• Electrical components of devices should be double insulated and have either a circuit breaker or a fuse.

Usability
The units evaluated were checked for the following in the usability category:

• Devices should weigh less than 27 kg, be stable and resist tipping, and be easy to manoeuvre with at least two casters.

• If warm-up time exceeds 2 min, the unit should indicate when warm-up is completed.

• Devices should not generate more than 60 dB of noise when operating at the maximum flow. Less than 45 dB of noise is preferred.

• User manuals should be available in English, Spanish, and French, should be included in the box with the device, and should be readily available on the manufacturer’s website. 

• Changing the cabinet and feed filters should not require tools. Cabinet filters should be washable.

• To accommodate health facility settings:

  • Settings should be easy to read from an angle and distance.

  • Controls should be durable, secure, and be hard to change if inadvertently bumped.

  • Readily accessible user information (e.g., QR code on unit that leads to user manual, quick reference guide attached to unit) is preferred.

• Notifications should be visible on the units to remind users and/or technicians to clean and change the gross particle and compressor intake filters respectively.

Repairability
The units evaluated were checked for the following in the repairability category:

• Filters should be easy to access and remove for cleaning or replacement. The user manual should include filter cleaning/replacement instructions and frequency. Units should have labelling that indicates the frequency of filter cleaning/replacement and a warning about not using wet filters. Alerts or other indicators that filters should be cleaner/replaced are preferred.

• Units should have ultrasonic oxygen sensors for reliability and longevity.

• Units should display the total hours of operation.

• Units should be able to be cleaned with standard hospital cleaning and decontamination materials (e.g., bleach).

• Units should be well-made with all components securely mounted.

• Removing the enclosure and internal components should not be excessively complicated or time consuming. Performing basic repairs should not require specialised tools.

• Active troubleshooting displays/job-aids are preferred within the enclosure to help technicians whilst working. 

• Indicators for the status of the compressor and/or sieve beds, “service needed” messages to a provider, and the ability to download diagnostic information are all preferred.

• The user manual should include clear troubleshooting information. Troubleshooting information or guides on or attached to the unit is preferred.

Electrical resilience
The units evaluated were checked for the following regarding electrical resilience:

• Units shall comply with IEC 60601 and operate normally between -15% and +10% of their rated voltage.  It is preferred for equipment to be able to perform under grave deviations from their rated voltage, see findings within WHO PQS Devices Catalogue  specifications for cold chain hardware as an example benchmark.

• The ability to withstand exposure in 50 V increments up to 500 V and continue to operate is preferred.

• Units should protect themselves from exposure to transient voltage surges up to 2 kV (over 8.5x their rated operating voltage).

Energy efficiency
For this category, products were assessed for:

• Power efficiency must be ≤ 70 W / L/m

• A soft-start feature is preferred to reduce the in-rush of current at start-up (a particular advantage to not oversize an inverter if reliant on solar power), but to also overburden a health facility electrical system which could cause a short circuit.

• Power variability in line with flow is preferred, with:

  • Power consumption scaling with flow rate

  • Power usage of < 40 W / L / min.