Oxygen Manifesto, Part 2: the Devices (Advice from 3 Respiratory Specialists)

Oxygen Manifesto, Part 2: the Devices (Advice from 3 Respiratory Specialists)

Note: This is the second article in a three-part series written in collaboration with respiratory therapist Mark W. Mangus Sr., RRT, RPFT, FAARC, and oxygen expert Ryan Diesem. The first part can be found here.

When it comes to home improvement, people typically want three things from a contractor: good, fast, and cheap. Under all but the most rigorous (and lucky) circumstances, you can choose any two of the three. What this means is that you can have it good and fast, but chances are, it’s gonna cost you an arm and a leg. And while you may be able to get it fast and cheap, I can assure you that it probably won’t be that good. Or you may also be able to get it good and cheap, but it’s not gonna be fast. This could be why we can never get in touch with our contractor (once they have your deposit, of course).

There is a similar scenario occurring in the world of supplemental oxygen. People want three things. They want a delivery system that will be small and lightweight. They want a system that will last a long time. And they want a system that will provide a high liter flow, AKA a lot of oxygen.

Well, guess what? You can choose any two. What this means is you can have a system that is lightweight and long- (or more likely, medium-) lasting, but it’s not going to give you much oxygen. You can have a system that is lightweight and delivers a lot (or at least a moderate amount) of oxygen, but it’s not going to last very long. Or you can have a system that gives you a fair amount of oxygen and lasts for a fair amount of time, but it definitely won’t be light.

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I tell you these things (as I have for more than two decades) not to scare you nor for the sole purpose of putting the oxygen companies on blast (although many of them definitely need to be on blast). I tell you these things because I think it’s important for you to understand that the medical oxygen system is rigged, and not in your favor. And the systems themselves can be very confusing, even for many clinicians.

It also involves money, and as you know, often when a situation involves money, that’s when a lot of wolves — whose primary objective is to line their own pockets — come out in sheep’s clothing. Well, think of me as Little Red Riding Hood here to help you see the wolf for who he or she really is and to help you get the best oxygen delivery system for you.

It’s sort of like the Seinfeld episode where Kramer comes up with a coffee table book about coffee tables. Well, it’s sad to say, but we need a better supplemental oxygen system for supplemental oxygen systems.

Recently, I received a phone call from a longtime patient named Mrs. M., inquiring about a new portable oxygen concentrator (POC) she was planning to buy with her own money. She was told by one of the company’s sales agents that the device could provide up to 6 liters per minute (lpm) of oxygen. I assured Mrs. M. that this could not possibly be true because no POC exists that is capable of delivering 6 lpm. She was sure this was what the representative told her, so I asked her to have them call me.

I soon received a phone call from that person’s sales manager, who finally and reluctantly conceded that the numbers were actually manufacturer’s settings, not liters per minute. I wondered to myself if this was in fact a light bulb moment for him.

We eventually agreed that on a setting of six, the device would provide 1,260 ml of oxygen (1.26 liters) per minute, which I stated would not be enough for Mrs. M.

To be clear, Mrs. M. has been my patient for a very long time, and I have been a cardiopulmonary physical therapist for a very long time (27-plus years). So, when I stated that the POC in question would not meet my patient’s needs, I wasn’t telling the gentleman what I think. I was telling him what I know.

He then went on to oxygen-splain that that was why there was a 30-day money-back guarantee. Ohhh. We also discussed the “re-stocking fee,” which he assured me would be waived if the machine did not meet Ms. M.’s needs. How generous (yes, while I know you probably find this hard to believe, I am being sarcastic).

Well, guess what? The following week, I tested the device with my patient, and sure enough, it didn’t even come close to meeting her needs (as I knew damn well it wouldn’t).

So now my patient is in the uncomfortable position of having to return the device and, as you can imagine, deeply disillusioned because she was promised a rose garden full of lightweight oxygen that loves you long time.

But there is something even more important that should be considered. We are talking about supplemental oxygen, not a non-stick frying pan, not a mattress, and not a prom dress; oxygen: a crucial life-sustaining substance, without which people can get hurt or die.

Think of it like a parachute or the air bag in your car. If they don’t actually do what they are supposed to do in the way they are supposed to do it, well, that 30-day money-back guarantee really won’t be of much use, will it?

It is for all of these reasons that my goal is now, as it has always been, to help you gain the greatest understanding of your oxygen requirements, as well as how to ensure that these requirements will be met, so you can truly get the best system for you and use it to your maximal advantage. I will explain these concepts using simple terms and descriptions, leaving out the scientific mumbo-jumbo you don’t need to know in order to choose your best device.

The rest of this piece will be composed of concepts that every prospective oxygen user should understand, and you can put them in the bank like money, meaning they are definitely correct. If you don’t believe me, you can ask Mark Mangus. If you don’t believe Mark, you can ask Ryan Diesem. If you don’t believe any of us three, well then just stop reading now because there’s really no hope for you. OK. Here we go.

Oxygen by any other name …

Oxygen can come in one of three basic forms. It can come as a gas, as in a metal tank or cylinder; it can come from a concentrator, which can either be stationary, as in those plug-in home models, or portable (POC); or it can come as a liquid. There are upsides and downsides to each one of these delivery methods, and often, it comes down (or should come down) to making the best choice for you (or availability, as is the case of liquid oxygen, which I will discuss at the end).

As a general rule, oxygen coming from a tank will be purer than that coming from a stationary concentrator, meaning that 2 (or 3 or 4) lpm from a tank will have a slightly to more than slightly higher percentage of oxygen. In the case of most tanks, this should be 100% medical-grade oxygen and, depending upon the regulator used, can go as high as 25 lpm. When it comes to the home stationary plug-in units, some can go as high as 10 lpm, just slightly less pure than the tanks.

It also means that 3 lpm on a tank will likely keep you slightly (or somewhat more than slightly) more saturated than 3 lpm on a stationary concentrator, and although they are supposed to be equal, I can assure you they are not. This is why your oxygen saturation is so much higher on that big, beautiful, green and silver tank you use at rehab compared with your shorter, squatter (think R2-D2), slightly less beautiful concentrator sitting in your living room.

This brings me to my next point, which is why I used 3 lpm as my example. At this moment in time, 3 lpm is the maximum amount of oxygen that can be delivered continuously by any POC. Period.

While this may not be what you want to hear, it is what you need to hear so that if a sales rep tries to tell you that their unit goes up to 6 lpm, you can say without a doubt that 6 refers to a manufacturer’s setting, and not liters per minute. Any higher number than 3 definitely refers to a manufacturer setting that definitely corresponds to a substantially lower liter flow.

At this moment, liquid oxygen provides the closest we can get to having all three wishes granted by the same unit, in that it’s lightweight, has a long duration, and provides high continuous liter flows. In fact, for those reasons, I think a great name for these units would be The Genie. The problem is, for most people, genies don’t really exist.

Due to a lack of adequate reimbursement from the Center for Medicare and Medicaid Services (CMS) and other third-party payers, liquid oxygen has become increasingly difficult for suppliers to provide and, consequently, nearly impossible for many patients to obtain. I am currently working with a team on a new product and a system that will hopefully solve this problem, but it is also crucial for patient advocacy groups to keep the pressure on Washington.

There are other important factors that would be helpful for you to know about liquid oxygen, but I prefer to address those as an independent subject. Yes, it’s that important.

Continuous Versus Pulsed Delivery

As the names imply, continuous oxygen is delivered continuously, meaning it is always flowing. Pulsed-dose oxygen will provide intermittent bursts of oxygen, typically triggered by breathing in through the nose.

All three forms of oxygen (tanks, concentrators, and liquid) can potentially provide both continuous and pulsed oxygen depending upon the device and the accessory equipment used, and if you think about why this is so, it should make perfect sense.

Tanks can run continuously or with the help of a conserving-type regulator. They vary in size and weight, and have the ability to provide high (or at least moderate) liter flows. These two factors will determine how long they will last. In other words, the larger the tank, the longer it will last. The higher the liter flow, the shorter it will last.

Home (plugin) concentrators are able to provide high liter flows (up to 10 lpm on some models) due to the increased size and number of sieve beds, the filter that separates the nitrogen from the oxygen in the air. In addition, they don’t have the same time constraints as portable units since they run on AC electricity as opposed to a battery. As such, they are neither small, lightweight, nor are they very portable, although most are on wheels so you can move them around the house more easily. Two scenarios you need to be prepared for would be either equipment malfunction or a power outage. So if you do rely on a home concentrator, please make sure you have a few tanks on hand as a backup.

The single best source I have found related to portable oxygen concentrators, particular the actual devices themselves, is the Pulmonary Paper’s annual Portable Oxygen Concentrator Guide, written by oxygen super-guru and soon-to-be-respiratory-therapist Ryan Diesem. The guide provides excellent descriptions, as well as specifications, for the vast majority, if not all, available units.

While my goal is never to reinvent the wheel, there are a few points I want to make that will help you use the guide to your maximum advantage in deciding which unit to buy (or not to buy) –Will Shakespeare.

When comparing POCs with one another and with other delivery systems, be sure to check the maximum oxygen production in milliliters (ml) per minute. If you divide this number by 1,000, you will get the maximum amount of oxygen that the unit can produce in liters per minute.  As an example, a unit that can produce 3,000 ml per minute produces 3 lpm, regardless of the number of settings it has. A device that produces 1,050 ml per minute provides 1.05 lpm, and a unit that produces 680 ml produces 0.68 lpm, not even 1 lpm. How is that for perspective? For the 2019 guide, Ryan even did the math for you, which is a super-valuable addition.

So, if you require 6 lpm with a non-rebreather mask to stay saturated during your pulmonary rehab sessions, it is highly unlikely that one of these units will meet your needs. In the case of Mrs. M., even though the unit had six settings, the maximum oxygen delivered was still only 3 lpm, which is one of the reasons why it couldn’t keep her saturated unless she was at rest (which sort of defeats the purpose of a portable unit). We will discuss some of the other reasons in the next installment.

All the above commentary assumes that all other factors are created equal and that they all take place in an ideal world, neither of which is usually the case. For this reason, it is crucial for you to understand the other factors that will either make your device more or less acceptable to you and how to get the maximum effectiveness and greatest bang for your buck, regardless of manufacturer, unit, or delivery method.

These include factors such as whether you use a nasal cannula versus a mask, as well as using the correct breathing techniques to ensure the oxygen makes it into your lungs, regardless of the delivery device. These factors will be discussed next month in the third and final installment of the “Oxygen Manifesto,” along with this piece and “Oxygen Manifesto Part 1.”

Below is an excerpt from a letter I wrote to an unnamed POC supplier on behalf of my patient. I share this (with Mrs. M.’s permission) to help you to navigate the system more effectively and to help you hold companies more accountable.

To whom it may concern:

 Recently, I received a phone call from my longtime patient, Mrs. M. inquiring about your new [insert company and model number here]. She was told by one of your sales agents that the [model] provides up to 6 liters per minute of oxygen. I assured Mrs. M. that this could not possibly be true because there is no POC capable of delivering 6 liters per minute. …

 I then spoke with a manager at your company who began the conversation by stating that the [model] goes up to 6 liters per minute before acquiescing that the numbers were manufacturer’s settings and not actually liters per minute. …

 We eventually agreed that the (model) on setting 6 would provide 1,260 ml of oxygen (1.26 liters) per minute, which I stated would not be enough. … I tested the device with Mrs. M. and sure enough, it didn’t even come close to meeting her needs.

 So, now, what I would like is for Ms. M. to be able to return this device, no questions asked (because I have answered them all here) and with no restocking fee.

 But there is something even more important that I think you should consider. … 

 It is crucial from a safety and ethics perspective that your agents first and foremost know and understand the truth; that the pulsed settings on a POC are just that; settings and NOT lpm.

 Second, it is crucial from a safety and ethics perspective that your agents share that truth … with the patient, even if it means acknowledging that the device will likely be insufficient in meeting their needs and therefore, not shipping (selling) the device. …

 Also, please keep in mind that when patients are living with a chronic illness, especially one that makes it difficult to breathe, they are willing to try almost anything to reclaim their independence and their lives. This makes them particularly susceptible to high, and sometimes even not-so-high-pressure salesmanship. That’s the ethics portion of the equation.

 I understand that sometimes (even though they should), patients are not always properly field-tested or educated on exactly how much oxygen they need under which situations or what device will meet those needs. But if a clinician is telling you that it won’t, please go ahead and believe them and do the right thing by the patient. …  

 Please help Mrs. M. smoothly return her [model] without any glitches. … 

Thank you in advance for your cooperation.


Dr. Noah Greenspan

Dr. Noah Greenspan, DPT, CCS, EMT-B, is a board-certified Clinical Specialist in Cardiovascular and Pulmonary Physical Therapy, with more than 25 years of cardiopulmonary physical therapy and rehabilitation experience. His book “Ultimate Pulmonary Wellness” — a continuing source of pride — was published in 2017, and he has made it available for all to read online free-of-charge using that link or by going to the center’s website, www.PulmonaryWellness.com. His “Ultimate Pulmonary Wellness” Lecture & Webinar Series is also open to attend free-of-charge on the website.

Dr. Greenspan founded the Pulmonary Wellness & Rehabilitation Center, a Manhattan-based physical therapy practice specializing in the care of patients with cardiovascular and pulmonary diseases, in 1998. Under his direction, the Center has conducted over 100,000 exercise sessions and has been named “Best of the United States” in the area of cardiovascular and pulmonary physical therapy.

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  1. Geoff Mason says:

    I live in the UK, and have had PF for 9 years, i wish i had an understanding GP, as about 6 months ago i noticed my breathing was getting quite laboured do i went to see my GP, and asked about oxygen as sometimes it is difficult to get “air in”…I know this is a progressive disease but she (my doctor) said Oh you don’t want to go on oxygen your lungs will not work without it. As my consultant signed me off because she told me she could do no more for me, anyway its getting difficult to move about now, the easy tasks are now hard work. Anyone with yourself as their doctor is very lucky

    • Noah Greenspan says:

      I am sorry to hear this. In my opinion, a huge disservice by not recommending oxygen earlier. Now, need to get on it (if not already) and get moving.

  2. Donna Pioli says:

    I have had PF for going on16 years. I’ve gone to Dr Raghu since the beginning. I am 75 years old.. I have an Inogen3 and from what I read it only goes to 3lpm, no matter what it says. It is POC and I have 2 batteries which run for 5 hrs each. I am on 2lpm My question is how do I know what number? Or do those “papers” you mention tell me?

    • Noah Greenspan says:

      Hi Donna: Although I don’t know Dr. Raghu, I have heard many good things. What I tell people quite simply is “rely on your instruments,” meaning check your saturation and act accordingly, meaning use the lowest EFFECTIVE dose. This means the lowest setting that keeps you in the 90’s with 93%-plus being my personal preference. The issue with most concentrator is that many people need the maximum amount or more than the POC can produce. In this scenario, you have to keep it turned all the way up or get a more powerful device like a tank or liquid oxygen. My opinion.

  3. Jane Garrett says:

    Thank you for the informative article.
    I hope you answer a question for me. Say a continuous feed concentrator puts out 4 lpm, but we are only inhaling during half of that minute, exhaling the other. Wouldn’t it be the same (as far as o2 we get) ,as 2 lpm on pulse which is only put out by the machine when we inhale?

  4. Jan Riche says:

    I need more than 10 liters to move about. This means I spend most of my time in bed. I tried to get liquid o2 but could not even find a source. It is particularly galling as I have no other conditions, I am fully functional except for my IPF. Not having access to liquid 02, I believe, condemns me to invalid status.
    Is there anyone I can phone, write, or message to advocate for IPF patients that are coming after me. I just started hospice so any change in Medicare will come too late for me but IPF will still be affecting others.

    • Noah Greenspan says:

      Hi, Jan: I am so sorry to hear this. There are many advocacy groups currently working on making liquid oxygen more available including the Pulmonary Fibrosis Foundation among others.

      One thing I will say is that using 10 liters per minute, you should be able to get around using a tank. Ideal? Definitely not but doable. You will also be helped by using a non-rebreather mask which will allow you to use a lower liter flow. This and other suggestions will be discussed in detail in part 3.

      Please let me know if you have any additional questions or comments.


  5. Steve Dragoo says:

    Hey Dr. Greenspan,

    Thank you fro this clear and terrific article! It is a gift to have such advocates on our side such as yourself.

    Knowing the unit’s maximum ml seems like a complete definition on an individual patient’s needs to help determine the right equipment.

    Your article is timely. I am in the Philippines for a while and see a pulmonologist Wednesday as I would like his recommendation on a concentrator over here.

    Years ago in the corporate world I had to write a response that needed to shake the roots of a client or lawyer from time-to-time and would always add a C.C. to my favorite attorney. Always received a fast response…

    Thanks again,

  6. Lynette Francisco says:

    Thanks for excellent timely article. I have copd n lung cancer (in remission). I am on continuous oxygen 2l. I had pulse poc n it was not enough for me so doctor prescribed continuous poc which weigh 10 lbs no heavy to maneuver alone so I went back on tanks recently dr n supplier said they are getting away from tanks n trying to get patient accustomed to poc. I am now using poc setting 3l. It is ok saturation stays in 90’s. What is your take on this. I am stage 4. Thanks

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