Oxygen concentrators draw in ambient air (approximately 21% oxygen) and separate the nitrogen to deliver a higher concentration of oxygen gas. The purity of this output gas determines the effectiveness of the prescribed therapy. Maintaining consistent oxygen purity is linked to a user’s health, as a drop in concentration prevents the body from receiving the necessary therapeutic dose. Regularly checking the machine’s output ensures the device is functioning correctly and delivering the required oxygen level.
Identifying the Necessary Measurement Tool
The only reliable method for measuring the output of a home oxygen concentrator is by using a specialized device known as an oxygen purity analyzer. These handheld devices are calibrated to assess the percentage of oxygen concentration within the gas stream. The analyzer provides a direct, numerical reading of the machine’s performance.
A pulse oximeter, which clips onto a finger, measures a person’s blood oxygen saturation (\(\text{SpO}_2\)). While a low \(\text{SpO}_2\) reading may suggest a problem, the oximeter does not measure the purity of the gas coming out of the machine itself. For an accurate assessment of the equipment, obtaining or renting a dedicated purity analyzer from a medical equipment supplier is necessary.
Step-by-Step Testing Procedure
Before beginning the measurement, the oxygen concentrator must be powered on and allowed to run for at least five to ten minutes to stabilize its internal components. This warm-up period allows the sieve beds to reach optimal operating efficiency. Ensure the flow rate on the concentrator is set to the exact liters per minute (LPM) prescribed by your healthcare provider, as purity can fluctuate with flow setting.
The next step involves connecting the analyzer to the concentrator’s oxygen output port. This is typically done using a small piece of tubing to create a secure, airtight connection between the machine’s nozzle and the analyzer’s inlet. Some users connect the analyzer directly to the end of the nasal cannula tubing for a reading closer to the point of use. A tight seal is necessary to prevent ambient air from diluting the sample, which would result in an artificially low reading.
With the concentrator running and the analyzer connected, initiate the measurement function on the meter. The analyzer will draw a small gas sample and display the concentration percentage on its screen. Wait for the reading to stabilize, which usually takes a few seconds, before recording the final purity number. Repeat this test one or two more times to confirm the consistency of the result.
Understanding Purity Readings and Safety Thresholds
For most home oxygen concentrators, the standard acceptable purity range is between 90% and 96%. This range ensures the oxygen delivered is of therapeutic quality and provides the intended medical benefit. Purity levels slightly below this range, such as 87% to 89%, may still be acceptable depending on the device and flow rate, but they signal declining machine efficiency.
A purity reading that falls below 82% to 85% is considered a failure point and indicates the oxygen is no longer providing adequate therapy. International standards recommend that concentrators activate a low oxygen concentration alarm before purity drops below 82%. If your analyzer displays a result in this low range, the oxygen output is insufficient to treat your condition effectively, rendering the machine medically ineffective.
Troubleshooting Low Purity Readings
If the purity analyzer indicates a reading below the acceptable threshold, first check for simple, external issues that may be restricting the machine’s performance. Begin by inspecting the air intake filters, which can become clogged with dust and debris, starving the compressor of the air required for the separation process. Cleaning or replacing these filters according to the manufacturer’s instructions is the easiest first step.
You should also check the oxygen tubing and nasal cannula for any visible kinks, blockages, or leaks that could be impeding the flow. Ensure the concentrator is placed in a well-ventilated area, away from walls or curtains, as restricted airflow around the unit can cause it to overheat and reduce its efficiency. After addressing any external issues, turn the machine off and then on again, allow it to warm up, and retest the purity.
If the purity remains low after these basic checks, the issue is likely due to internal component degradation, such as worn sieve beds. In this scenario, immediately switch to a backup oxygen source, such as a reserve tank, if one is available, and contact your equipment supplier or healthcare provider right away. Continuing to use a concentrator with a purity reading below 85% can compromise your health, and the device will require professional service or replacement.