Supplemental Oxygen: Taking the First Steps

This article was reviewed by Senior Director of Community Engagement and COPD360social Community Manager, Bill Clark, as well as certified staff Respiratory Therapists on February 5, 2020.

Dear COPD Coach,
I was diagnosed with COPD about 5 years ago. My doctor has just prescribed the use of supplemental oxygen. What do I need to do next?

-Looking to Breathe

Dear Looking,
The first thing you should do is discuss with your doctor what type of delivery system is best for you. This discussion should include addressing your needs not only at home, but also when you are out and about. Be sure to document your discussion. Your doctor will then provide a certificate of medical necessity indicating that you require supplemental oxygen and what equipment you will need. Make sure this certificate of medical necessity contains all of the items you discussed.

Your second step is to identify an oxygen supplier that is able to address the needs set forth in the certificate of medical necessity. Know that your oxygen supplier is not your doctor and cannot make decisions about the type of equipment you require- only you and your doctor may do this! Once you are provided equipment, you generally cannot change the type of equipment or type of delivery system for a term of five (5) years. Note: if your oxygen requirements change, your certificate of medical necessity should be updated. Your oxygen supplier is obligated to provide equipment that fits that need with a new certificate of medical necessity.

There are two main types of supplemental oxygen- gaseous and liquid. There are pros and cons with each system, as well as different variations. In the past, many oxygen users were given both a home concentrator (for use while at home) and a cylinder (for going out). This arrangement was problematic because it required users to pull the cylinder behind them when venturing outside. A user's mobility was limited to the length of their oxygen hose inside the home, making some areas inaccessible.

A recent advancement is the development of "transfill" units. In this system, gaseous oxygen can be produced in the home by a concentrator and stored in a refillable cylinder. These cylinders (tanks) are small, light, and can easily be carried in a shoulder case. The length of time these smaller tanks last varies on your liter flow and the amount of pressure the cylinders contain. Note: some transfill units will fill at 2000 psi (pounds per square inch) while others fill at 3000 psi. The higher pressure provides greater capacity. This system provides you with greater mobility outside as well as inside your home and eliminates your need for frequent replacement tanks. The entire system is transportable if you need to leave your home for extended periods.

The other modality is liquid oxygen, a popular option with higher liter flow users. In this system, the oxygen is stored in liquid form in a home reservoir which must be filled on a regular basis. You are able to use the reservoir much like the concentrator, using it to fill smaller reservoirs for greater mobility inside or outside the home. These smaller reservoirs offer longer use times even at higher liter flows. The other advantage of this system is that it is not dependent on electricity like a home concentrator. This means that oxygen use will not add to your utility bills and you will continue to have oxygen during power outages. The main disadvantage of liquid oxygen is that the reservoir cannot be transported with travel (unless your oxygen provider allows you the use of a travel reservoir), so you must make arrangements to have a reservoir in place at your destination. Note: in many areas it is difficult to obtain liquid oxygen. Check with suppliers in your area before deciding on liquid oxygen to make sure it is available.

Be sure to discuss all of these options with your doctor!

-The COPD Coach

Coaches Corner is aimed at providing information for individuals with COPD to take to your doctor, and is not in any way intended to be medical advice. If you would like to submit a question to the Coaches Corner email us at We would love to hear your questions and comments. You can address your emails to The COPD Coach.


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  • Dear Breathing......My advice to you is be sure to get help and understand how to use the tanks.
    They brought mine out to me, installed everything, told me once how to use everything, and left.
    I was scared to death of it and knew I'd blow up that evening! I called the office a few times with questions and finally they sent a therapist out who explained it better to me, showed me how to use it, change bottles easily, adjusted tubing, and I was so thankful for her. I've heard of other older people who are afraid of it till they get used to it, so get it explained!
  • While you and your doctor are the ones to make the decisions regarding the type of equipment and the amount of O2 that is prescribed, you do need to understand that not all docs know much of anything about home O2 delivery systems. In my experience, most of them think that O2 comes from the walls in hospitals and have no idea what a concentrator actually does (besides creating O2, it also creates a lot of heat and adds significantly to your electric bills). He probably has no idea how long a B or C tank will last given the liter flow he's prescribed for you, so he has no idea how many of those tanks you would need to take with you in order to see a movie, for instance.

    I realize this isn't very comforting, but there are sources of information, one of which is the Foundation's hotline. I suggest that you do your homework well ahead of time, think about your lifestyle now and what you want it to continue to be, think about your physical abilities (how much you can carry or drag, as the case may be), what you need for exercise, how much time you'd like to be gone from home for your regular activities so you know how many of the small tanks to take.......everything you can think of. Then talk with your doc. Maybe he can write the prescription so you can try some things before deciding on one system (I'm not sure that's possible, but it's worth a try!).