An oxygen concentrator is a medical device that provides supplemental oxygen by filtering nitrogen from the ambient air. The machine concentrates this oxygen to a higher purity, typically between 87% and 96%, before delivering it to the user through a nasal cannula or mask. Regularly verifying the machine’s performance is necessary to ensure the patient is consistently receiving the precise therapeutic dose prescribed by a healthcare provider.
Pre-Test Preparation and Visual Inspection
Before powering on the concentrator for testing, a basic external check confirms the machine is ready for operation. Ensure the power cord is securely plugged into a functional wall outlet, avoiding extension cords which can cause voltage issues. Confirm the machine is positioned in an area with adequate airflow, typically at least 12 inches away from walls, furniture, or curtains that could obstruct the air intake vents.
The concentrator relies on pulling in large volumes of room air, so the intake filters must be clean and properly seated. Remove the gross particle filter, often a foam or mesh component, and check it for accumulated dust or debris that could restrict airflow. After cleaning or replacing the filter according to the manufacturer’s directions, inspect the oxygen tubing and nasal cannula for any visible kinks, twists, or small holes. Damage or blockages in the delivery system can severely reduce the flow of oxygen reaching the user.
Checking Flow Rate and Alarm Indicators
Turn the machine on and allow it to run for a few minutes to ensure it stabilizes. The most direct user-level check is confirming the flow rate, which is typically set using a knob or button to align with the prescribed liters per minute (LPM). For continuous flow models, the flow meter features a ball that floats in a column, and the center of this ball must align precisely with the correct LPM marking on the gauge.
A simple way to verify air output is by performing a bubble test, especially if using a humidifier bottle, which is filled with distilled water. With the cannula connected and the flow set, submerge the tip of the nasal cannula or tubing in a glass of water. Consistent bubbling in the water indicates that gas is moving through the delivery system and exiting the cannula.
The concentrator’s lights and audible alarms provide immediate feedback on its internal status. A steady green light usually indicates the device is operating normally and producing oxygen. Different colored lights, such as yellow or red, or an audible warning, signal a problem like low pressure, high temperature, or a drop in oxygen purity. If an alarm sounds, consult the user manual to identify the specific issue.
Measuring Oxygen Concentration
The most definitive measure of concentrator performance involves measuring the purity of the gas output. This step is necessary because the machine might be running and flowing air, but the internal sieve beds—which separate nitrogen from oxygen—may be degraded and failing to concentrate the gas effectively. Medical-grade oxygen concentrators are designed to deliver a purity of at least 87% to 90%, with many aiming for 93% plus or minus 3%.
Measuring this concentration requires a specialized electronic tool known as an oxygen analyzer. This device is different from a pulse oximeter, which measures the user’s blood oxygen saturation, not the machine’s output. The analyzer is connected directly to the concentrator’s outlet port or the tubing line to sample the gas.
To get an accurate reading, the concentrator must be allowed to run for at least five to twenty minutes before the test begins, giving the internal components time to warm up and stabilize the oxygen production. The analyzer will then display the percentage of oxygen purity. If the reading falls below the medically acceptable threshold, usually 82% to 87%, it confirms that the machine is no longer delivering therapeutic oxygen. Because these analyzers are specialized and require periodic calibration, this measurement is typically performed by a trained technician or oxygen supplier during routine maintenance checks.
Troubleshooting Common Failures
If initial testing reveals a problem, such as a low flow rate or a persistent alarm, a few simple actions can often resolve the issue. If the flow seems low, check the humidifier bottle connection, as a loose or cross-threaded lid can cause oxygen to escape the circuit. Similarly, ensure the oxygen tubing and cannula are fully clear of any kinks, which is a frequent cause of reduced flow and triggered alarms.
If a low purity alarm activates, check and clean the external gross particle filter, as a clogged filter restricts the air intake necessary for the concentration process. For issues like a complete power failure, try plugging the unit into a different, verified working wall outlet and check the circuit breaker or reset button on the machine itself. If the concentrator sounds excessively loud or makes unusual noises, the internal components, such as the compressor or sieve beds, are likely failing. In these situations, the user should immediately switch to a backup oxygen source and contact the equipment supplier or a qualified technician for professional service.