Portable Oxygen: What's Right For Me?

This article was reviewed by Senior Director of Community Engagement and COPD360social Community Manager, Bill Clark, as well as certified staff Respiratory Therapists on January 29, 2020.

Dear COPD Coach,

I have had idiopathic pulmonary fibrosis (IPF) since 2009. I was an athlete. I did not smoke. I have been told I am de-saturated at night and have a concentrator for night use.

Based on my latest 6 minute walk test, my clinician’s impressions are the following: With treadmill titration, patient required 3L to maintain an oxygen saturation (SpO2) of 91% at a metabolic (MET) level of 4.8. Decrease in walk distance compared to January by over 350 feet. However, still with excellent effort on 6 minute walk test, but severe desaturation to 75% on 3 liters per minute of oxygen. With significant oxygen needs for higher exertion levels. Discussed paced activity, monitoring SpO2 with activity.

Is there any portable concentrator that is preferred (flow and weight) for moving around NYC on foot generally (walking, and going up and down subway stairs)? I realize that these questions, and my situation, are perhaps an anomaly, but hope the questions can be answered from your experience/knowledge base. Is there any portable concentrator OR other oxygen apparatus that is preferred/usable (flow and weight) for outdoor exercise (put of bike rack) that permits 6-8 liter per minute flow exercise (which was my use at rehab gym on treadmill, etc.)?

Thank you for any advice.

- Concentrator Questions

Dear Concentrator,

You pose some interesting questions. It is apparent that you are having a more difficult time keeping your saturations up during exertion as time goes on. However, increasing your ability to exert by using a portable concentrator becomes a little complicated. The problem is that it appears you are looking towards finding a smaller concentrator that will provide sufficient output to increase your saturations to an acceptable level, and there is a very real possibility that the concentrator you are looking for does not exist.

First off, there are two delivery systems for portable concentrators, “pulse” and “continuous flow.” The pulse machines deliver a specific dose (called a bolus) each time you breathe. This sounds like it would work well, other than two factors: As you increase the size of the bolus, you decrease the number of breaths that the unit is able to produce per minute. As a result, each breath past a certain number of breaths (usually in the 20’s) decreases the purity of the oxygen dose. A simple way of putting this is that by breathing faster (as you usually do when exerting) you might “over breathe” the unit.

Secondly, oxygen concentrators work by pulling in room air and forcing that air through a sieve bed containing a substance that separates oxygen (which is around 21% of the air we breathe) from the other gases (mostly nitrogen). The output of the unit as far as pure oxygen being delivered is controlled by the size of the sieve beds and the compressor. The pulse units are smaller and lighter weight because the sieve beds are smaller as are the compressors that fill the sieve beds. And, since the units are not running continuously, they can use smaller batteries.

A third factor with pulse units is that their output cannot be measured in liters per minute as they do not run continuously for an entire minute. The industry uses a measure called “equivalent liters per minute” which denotes the approximate size of one bolus as it relates to the amount of oxygen you might get with one breath using a continuous flow unit. But, it’s important to remember that the pulse unit is only able to deliver that bolus a certain number of times per minute before the oxygen dose becomes diluted.

That sounds complicated, but there’s actually more.

There is no standardization as to how the bolus is delivered; if it is extended over time or delivered in one burst.

The settings on the vast majority of pulse units do not denote their equivalent liter flow. For example, a pulse unit might have a setting of six but that does not mean six equivalent liters, when instead it might only deliver three equivalent liters at that setting (as I said, there are no standardizations). It also does not indicate the purity of the oxygen at that setting or how many boluses per minute the unit provides.

Some people are not able to use a pulse dose system because they require more breaths than the unit produces (they then over breathe the unit with means they are taking in larger amounts of room air as opposed to pure oxygen) or the size of the bolus is not sufficient for their needs. If this is the case, they simply cannot maintain their oxygen saturations at a safe level.

As far as continuous flow goes, the same restraints apply. In order to produce a constant flow, the sieve beds and compressor must be larger which then also means much larger batteries that don’t last as long. Because of these limitations, there are NO continuous flow portables that produce more than 3 liters per minute. The units that are out there are much larger and heavier than any of the pulse units. Most continuous flow portables also deliver pulse and can be used in both modes.

I know I haven’t answered your question totally as there is no definitive answer I can give you. The following is the best I can do:

Q: Is there any portable concentrator that is preferred (flow and weight) for moving around NYC on foot generally (walking, and going up and down subway stairs)? I realize that these questions, and my situation, are perhaps an anomaly, but hope the questions can be answered from your experience/knowledge base).

A: That would depend on the amount of exertion you plan on doing. I don’t believe any portable will be able to provide you with unlimited saturation without pacing yourself. I do not know if you would be able to use pulse or would require continuous flow. I use only use oxygen for sleeping and also have a home concentrator. However when traveling, walking long distances, or other situations where I do more than simple short distance walking, I use a portable oxygen concentrator. I use a pulse unit but in pretty much every case, I still must pace myself and still get out of breath. At times I over-breathe the unit.

Q: Is there any portable concentrator OR other oxygen apparatus that is preferred/usable (flow and weight) for outdoor exercise that permits 6-8 liter per minute flow exercise (which was my use at rehab gym on treadmill, etc.)?

A: As I said earlier, there are no portable units that put out that much oxygen. If there was, as technology stands, it would be too large to carry.

The best advice I can give you is to talk with your doctor and oxygen provider, and if possible try a couple different units to find what works best for you. I would NOT buy a unit before trying it first. I really believe that in your case you will have to end up settling for the unit that offers the best result for you even if that result is not what you hoped for as far as mobility. Make sure you get a pulse oximeter that you can carry with you as you measure your saturations!

One last thing: The larger the unit you have to carry, the more desaturated you will become. When I first started traveling with oxygen, the only unit available was a pulse unit that weighed 14 pounds and had to be pulled on a cart. I desaturated so badly that the unit could not keep up so it was pretty much useless.

Sorry I couldn’t be more help but please reach out if you have any additional questions.

-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 coachescorner@copdfoundation.org. We would love to hear your questions and comments. You can address your emails to The COPD Coach.


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  • If it is possible to get liquid oxygen prescribed and have your provider help you fight for it do you can stay saturated, that would be able to have these higher flow rates.
    Sadly not many places still have liquid oxygen, but for places where it is available, people like you who need high flow rates to be active are the perfect candidates.
    Another option to consider if you are using O2 24/7 is to consider transtrachael oxygen. Folks who have a cathater in their trachea to get their O2 often can use lower flow rates and their bodies are better oxygenated without their nose constantly being irritated. More info on it is here: http://tto2.com/what-is-tto2

  • As a 12 year user of Oxygen 24/7 Allow me to input. I gave up on the portable as I require at least 5 LPM CF for walking. Currently, use a D size backpack w/ tanks. This only lasts about an hour. The longer I'm at it the higher the LPM rate goes. They have what's called an oxygen pendant which boosts the oxygen required plus saves on the use prolonging having to change the tank so often. The main problem with this cannula is it's so stiff it makes it uncomfortable. Also might want to look into a NIOV which is a portable concentrator that attaches to a CF tank. I also need more info on this as it's a new thing. Sorry but it's a pipe dream to think those of us who require higher flow are going to find a lightweight unit. Maybe as the technology advances. keep on walking! Breathe on... Try pulmonary rehab to get educated


  • April 2018 my contract was up, the company sent papers. I gave them to the Pulmonarys Dr's Nurse., who has a habit of telling you which equipment that she thinks is nice. By the way she is a coordinator also. My Appt .was with my Primary Dr. in May, I asked him at that time would he order my oxygen equipment because I had not heard from anyone. He informed me that the equipment had been ordered on April 16th. The following week in may on a Saturday afternoon when the company was closed. Now this is my 5 yr. Bidding contract with my Medicare.. People have been trying to get me to drop my medicare and switch to a plan, I refuse to.

    To make a long story short, the concentrator delivered was a Black on wheels Portable Concentrator, with a refill placed on top, the original clr Beige. The Driver did not check my two portable tanks, he lied on the electronic sig, and said I was satisfied. I contacted the company and told them I did not recieve a manuel, they claimed none was in the office and they would send one out in the mail, and the manual was not for a "Drive DevilBliss" So I have no warranty, no invoice, and somehow they managed to Bill Medicare for only a Refill, They removed my original concentrator, and refill equipment.. So I decided to look at the companys product. the "Drive DevilBliss" they show is in a black Zipper Bag, it has a second part to it, it also sits on something and you can pull it. It just so happens that "CEDA/IHEAP" was doing work in my apartment, and one of the Inspectors told me that if I had to leave in case of an Emergency the concentrator was battery operated. The Driver who delivered it did not say so.. I visited the Drive website and did not see the "DevilBliss" product.

    I need a COPD Coach to contact "Revolve Orbit Medical", in Naperville,,find out who ordered the equipment, who was billed, where is the warranty, the invoice, and I want an "Supervisor or Inspector" from their Corporate Office to look at what was sent to my home. There is no way that Orbit DME who is contracted to do business with Medicare(all claims are done by Medicare in Nashville, not Illinois).. A supervisor needs to go over the records and do a home visit.

    I am fed up with attitudes that "Seniors are computer illterate" and that it is assumed that if you give them anything, or change an appt, hack a email they wont know the difference. Orbit will not answer phones, they constantly remove emails so you cant reach them, and when you contact them they answer in two days. I have pictures of the old equipment, the new equipment, and pictures where someone broke in an tampered a ER Tank.
    • I never heard of Liquid Oxygen, until I joined this group..

    • Hi Whylene,

      Have you tried contacting 1-800-MEDICARE to file a formal complaint? This is a critical step in getting action because they have to log the issue formally and then will triage it to the right regional group to try and get resolution if possible. You can also call and log the issue with our Info Line at 866-316-COPD,. They are trained to fill out a form and then with your permission we pass that info along to our ombudsman contact at CMS who can try to help as well. Hope you are able to get some answers and resolution.

  • I Just discovered this group and am VERY pleased. Though it seems I am much less afflicted than many on the site. My sympathies for all and my sincere thanks to all who try so hard to help.

    My diagnosis is Sarcoidosis which I understand to mean scarring of the lungs.

    Had some pretty significant asbestos exposure back in the '60s when nobody knew or at least nobody was warning us about the little "spears" killing our aleovi etc. (I probably just mis-spelled the name of those things that transfer oxygen from our lungs into our blood stream. Spelled it the way it sounds to me.)

    Impact of my COPD seems to be most severe when the Dew-point is in the 60s or higher. Gets really bad in hot humid weather.

    Since 2011 I have had a Pulmonary Specialist and an annual pulmonary test involving the deep breaths and long exhales etc.

    Last visit my Pulmonary Doc had me walk up and down stairs at the clinic and I never got below 91% SP-O2.
    But that was in an air conditioned building and on a bright sunny day. Dew-point probably in the low 50s outdoors and Heaven knows what it was in that A/C environment.

    In August 2017 I traveled in Italy from August 6 to September 6. Hot and Humid as Italy is that time of the year. Used my Inogen-1 G-3 continuously and was fine as long as I paced myself. Even climbed the tower of Pizza. VERY slowly but I did make it up there.

    I'm almost 80 now. But I was already on Medicare when affliction first presented itself around Labor Day 2011.
    Used Lincare for 5 years. Great service. But tanks not welcome on airplanes.

    Discovered Inogen and switched over in 2016.
    Apparently Medicare has a SP-O2 threshold of 88%. I only achieve that under certain atmospheric conditions and moderate exercise like stair climbing.

    Now Medicare doesn't want to pay Inogen because I'm not below the threshold. Is there an appeal process for we who only need supplemental O-2 seasonally?

    Has anybody already walked this mile?

  • Have you thought about using a walker in the future? I bought one that has a seat, and storage area under the seat. I have a Respironic Mini that I carry to use on an airline at altitude. I have a hard time carrying it, and still get breathless when I'm trying to walk with it. I'm to use oxygen if I go below 88 saturation, and that seems to happen more often. If it comes back up to 90 within 5 minutes I don't need to worry.

    If I can stop walking, and find a place to sit for a few minutes I have a much easier time. The walker will allow me to sit down and rest. The storage area under the seat will also carry the Respironic Mini, and a small purse. Another option might be an electric scooter if being able to sit down helps your saturation levels. I get so embarrassed when I have to put on oxygen, but need to bravely forge ahead. Best wishes to finding a way to get out and about.