Home Oxygen Concentrators: how do they work and what kind of maintenance do they need?

It’s a scary thing when someone you love can’t breathe well.  It may be due to chronic obstructive pulmonary disease (COPD), pulmonary or cystic fibrosis.heart failure, severe long-term asthma, or another condition.  The percentage of oxygen in their blood may drop below 92%, which is the normal threshold of which supplemental oxygen is needed, and their doctor may prescribe supplemental oxygen for home use.  Normal air contains about 20.9% oxygen, but if a person’s lungs are not working properly due to disease or other limitations, they need to breathe in a higher percentage of oxygen in order to get sufficient oxygen into their blood and tissues.  A home oxygen concentrator (HOC) delivers 90-95% pure oxygen, and this is delivered via a cannula (nosepiece) or mask with holes in it, so that they breathe in this nearly pure stream of oxygen, mixed with the surrounding air.   

Here is how an HOC works: (How Does an Oxygen Concentrator Work?) 

• The concentrator pulls in air from the surrounding environment.

• A compressor then compresses the air.

• The compressed air is passed through one of two sieve beds. Each bed is filled with a type of material called zeolite. Zeolite is a microscopic six-sided porous cube that has a strong affinity for nitrogen.  

• When the compressed air passes through the sieve bed filter, the nitrogen molecules are attracted to the zeolite and are trapped. The oxygen molecules, conversely, can pass through the filters and are collected in a product tank.

• The oxygen from the product tank is then delivered to the patient through a nasal cannula or mask. 

• When one sieve bed gets full of nitrogen, a control valve switches to send the compressed air through the other bed, while the first bed is flushed out and the nitrogen is expelled to the air. 

Source: How do oxygen concentrators work?

The most essential part of the HOC (besides the compressor) is the zeolite beds.  These are also called molecular sieves.  Zeolites are aluminosilicates, which is a type of mineral made out of aluminium, silicon and oxygen. They can be found naturally and then mined, or they can be manufactured synthetically.  (What is zeolite? What are zeolites made of?)  Zeolite research and customization is a growing industry, because they are used in many different applications.  Every HOC manufacturer has the option to customize the zeolites in their design to increase the efficiency of the machines.  However, impurities in the incoming air (like smoke, VOCs, particulates) affect zeolites negatively by taking up space in the material so that not as much nitrogen is adsorbed, or by preventing full adsorption of the nitrogen.  

Filters are employed to clean the air as it comes in and the oxygen exits the machine, but these filters vary by model.  The best type of filter would remove particulates and VOCs, typically with HEPA and activated carbon components, but many HOC’s only have a “gross particle filter” meaning that it’s typically a sponge type that only catches large pieces of dust, dander and hair.  

Since your loved one already has a compromised respiratory system, you’ll want to pay attention to perform recommended maintenance on the HOC to avoid possible infections.  Following are some typical maintenance steps for HOC’s; you should consult with the medical supply company for your model, and usually turn off the HOC before doing any maintenance.

Filter maintenance: Since most HOCs sit on the floor, filters can get very dirty and you’ll want to check them weekly.  The filter cover can be cleaned with a HEPA vacuum or washed with warm water and mild soap if it’s detachable.  If the filter inside is a gross particle filter (sponge/foam type), you can take it out and wash it in warm water and mild soap, then squeeze the water out and let it fully dry in the air before re-installing.  High-efficiency particulate air (HEPA) filters trap 99.97% of airborne particles, including dust, pollen, mold, and bacteria. HEPA filters typically look like white paper within a clear plastic. Monitor your HEPA filter quarterly, replacing it when the white paper appears dirty. (Home Oxygen Concentrator Maintenance Guide)

Humidifier maintenance: If the air is dry in the home or your loved one gets dry nasal passages, you can request a humidifier attachment to help increase the humidity of the oxygen coming out of the machine.  Typically it’s a clear cup attachment where you can add water, and distilled water is recommended for its purity.  The American Lung Association recommends cleaning it every time you refill it.  You can clean it with warm water and mild soap, taking care to use only a soft cloth to avoid scratches in the plastic, since bacteria thrive in those small spaces.  For this reason, don’t use a kitchen sponge!  Kitchen sponges can harbor a lot of bacteria as well.  After cleaning, rinse the removable parts with water and refill it with distilled water (typically only one-half full). 

Exterior maintenance: HOC’s take in room air and expel pure oxygen and heat.  Therefore it’s necessary to keep the intake of the HOC 4” or more away from the wall for adequate airflow and avoiding overheating.   After turning off the unit, you can use a damp cloth to wipe down the outside once a week.  

Running the HOC at least 10 hours per month (not necessarily consecutive hours) will keep the compressor parts oiled and help the sieve beds to function well.  (Home Oxygen Concentrator Maintenance Guide)  

If you have any model-specific questions, be sure to call your medical supply company.  Keep an eye on your loved one’s blood oxygen (typically using a small battery-operated finger sensor) so that it stays above 92% or whatever level the doctor orders.  If it drops while they are using oxygen, check all the hose connections to make sure they are tightly connected and not pinched or kinked.  The most typical prescription is for 2 liters per minute coming from the machine.  If necessary, this can be increased but only after consulting with their doctor, because too much oxygen can damage lungs.  

We know that caring for a loved one with respiratory problems can be taxing, but thankfully modern medical technology.  Reading and researching on their condition and available technology can give a lot of help and support. 

Photo by engin akyurt on Unsplash