Home (plugin) concentrators can 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 respiratory therapist and oxygen super-guru, 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) –William 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 1260 ml or 1.26 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 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 in the next section, which was 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.

YOUR NAME HERE

Oxygen Manifesto 3: Originally printed in Pulmonary Fibrosis News, August 5, 2019

Hell-O2 U, my fellow Oxygen Aficionados! This is the third installment of our “Oxygen Manifesto” series.

For this segment, I have enlisted the help of one of my cardiopulmonary physical therapy heroes, mentors, friends, and the mother of modern-day chest physical therapy and pulmonary rehabilitation, Dr. Donna Frownfelter, and one of my 28-year colleagues, friends, and chest physical therapy/secretion clearance guru, Marion Mackles. When I was a physical therapy student in 1992, we used the second edition of Donna’s textbook Chest Physical Therapy and Pulmonary Rehabilitation in our cardiopulmonary class; we are currently working on the sixth edition.

I hope that through this series, Donna, Marion, Mark Mangus, Ryan Diesem, and I have succeeded in providing you with valuable information in a clear, easy-to-understand format you can now use to help make the best oxygen decisions for you.

In these final segments, we want to tie everything together by discussing some basic concepts that are often overlooked, underestimated in their importance, or even unknown, as a way to further deepen your perspective on supplemental oxygen use, and give you a few simple “oxygen hacks” and insider tricks of the trade that can make a huge difference with respect to oxygen use and efficiency as well as your overall health and wellness. Let’s begin.

Pulmonary Anatomy and Physiology

Air can enter the body through either the nose or the mouth. When you breathe in through your nose, three important functions are performed. First, the air is filtered by tiny hair-like structures; called cilia, trapping particles of dust and debris in the mucus membranes. Second and third, the air is warmed and humidified by tiny blood vessels called capillaries.

From the nose, air continues into the nasopharynx, the uppermost part of the throat. When you breathe in through your mouth, air passes through the oropharynx, the middle part of the throat. The nasopharynx and oropharynx meet in the back of the throat, or pharynx, and continue down through the laryngopharynx, the lowest part of your throat and the larynx (also known as the voice box).

From the larynx, air enters the trachea, or windpipe, through the epiglottis, a flap of cartilage that opens during breathing and closes during swallowing to prevent solids and liquids from entering the trachea, airways, and lungs.

The trachea then splits into the right and left mainstem bronchi, going to the right and left lung, respectively. The bronchi then continue to divide, getting smaller and smaller, branching into secondary and tertiary bronchi and even smaller bronchioles. After approximately 20 to 23 divisions, the air finally reaches the alveoli, the tiny air sacs in the lungs where gas exchange occurs.

Efficiency, Effectiveness, and Miles Per Gallon

If you think of your body like a car, the efficiency with which your body uses oxygen is like how many miles you get per gallon of gas (mpg). If you are out of gas, even the most beautiful car will sit idle without fuel to power it. If your engine is run down, your oil badly needs changing, or your tires don’t have the proper amount of air in them, your car will be less efficient and get fewer miles per gallon. The same is true when it comes to your body.

Good News!

Here is the good news, though, and again, we are completely biased. But in our experience, we have found that the right combination and type of exercise and breathing techniques can significantly improve the effectiveness of the respiratory, cardiovascular, and muscular systems, thereby improving your body’s overall efficiency at using oxygen.

In addition, despite a large body of scientific literature stating the opposite, we firmly believe that under the right conditions, your pulmonary function can also improve. In the Exercise chapter of Ultimate Pulmonary Wellness, I explain what makes our training methods so different, so effective, and what we believe is the key to improving pulmonary function. Understanding these principles will hopefully allow you, the patient, as well as other rehabilitation professionals and programs, to benefit from what we at the Pulmonary Wellness & Rehabilitation Center know to be true.

Ventilation and Respiration

The mechanical act of moving air in and out of the lungs, i.e., inhalation and exhalation, is called ventilation. Ventilation is an active process, meaning it requires the contraction and relaxation of the respiratory muscles for it to occur.

The chemical exchange of oxygen (O2) and carbon dioxide (CO2) between the external environment and the cells of the body is called respiration or gas exchange. Respiration is a passive process and occurs constantly, regardless of muscle activity or phase of ventilation. In other words, it occurs at the cellular level, during both inhalation and exhalation, as well as during any pauses in between.

Breathing Pattern is Still King (or Queen)

Regardless of whether you use supplemental oxygen or not, breathing pattern will play the greatest role in how well or how poorly we breathe. When we are talking about breathing pattern, we are referring to variables such as your respiratory rate, rhythm, and depth, as well as which muscles are being used. Our breathing pattern can be affected by many factors including our anatomy (i.e., “normal chest wall” versus a scoliosis, or pectus excavatum, or asymmetry, which can occur in a person who has had a stroke), physiology and pathophysiology, pain, environment, and even our emotions, among many others.

Respiratory Rhythm

Normal, unlabored breathing (also sometimes called quiet breathing) is known as eupnea and should be regular or steady. Abnormal, irregular, or labored breathing is called dyspnea, and is closely related to a person’s shortness of breath (SOB) or perception of breathlessness.

Musculature and Symmetry

During normal breathing, the chest and abdomen should rise and fall together as the diaphragm, the main inspiratory muscle, contracts, and the lungs fill up with air. The initial movement is seen in the upper abdomen just below the xiphoid process, the lateral lower chest moves up and out to the sides, and if the breath is large, the upper chest will move. In quiet breathing, basically the upper abdomen and rib cage move. It is when we take deeper breaths, we see the upper chest move. The same is true for when the diaphragm relaxes, and the lungs expel air.

During labored breathing, accessory muscles of the neck, shoulders, chest, and back can be recruited. Other signs of distress might include nasal flaring or tripod position, in which a person will lean forward with his or her elbows on the thighs when in a seated position, or bending over, leaning forward on the upper extremities (or something else) when standing.

Generally, both sides (right and left) of the chest should move symmetrically or equally. An asymmetrical breathing pattern is abnormal and can indicate a physical or physiological problem.

Respiratory Rate (RR)

Respiratory rate (RR) refers to how many breaths we take per minute, i.e., how fast (or slow) we breathe. In adults, normal respiratory rate is 12 or in some references, 10–20 breaths per minute. A respiratory rate of greater than 20 breaths per minute is called tachypnea and a respiratory rate of less than 12 breaths per minute is called bradypnea.

Depth or Tidal Volume (TV or Vt)

Depth of breathing refers to how shallow or deep we are breathing and represents the inspiratory, or tidal volume (TV or Vt), i.e., the amount of air we breathe in and out with each breath.

Minute Volume (MV)

Minute ventilation can be described as the amount of air we breathe in and out in one minute and can be represented as RR x TV, in other words, the number of breaths we take per minute multiplied by the amount of air we breathe in and out with each breath.

Overcoming the Trachea

 The trachea, or windpipe, is known as anatomical dead space because, as opposed to being able to perform gas exchange, it is simply a conduit and does not allow oxygen to enter the blood where it can be used by the body. Think of it like a jet bridge, the corridor at the airport that takes you from the waiting area at the gate to the plane. You can be anywhere along that 150-foot tunnel, but unless you make it onto the plane, you’re not going anywhere. It is, in fact, just a conduit that must be passed for our breathing to be effective.

The volume of air in the trachea can very roughly be thought of as approximately as many milliliters as your weight in pounds, so for the purposes of this example, we will use a 150-pound person, and therefore, the trachea will account for 150 milliliters of air.

6 Liters Per Minute

On average, most of us breathe approximately 6–8 liters per minute (6,000–8,000 milliliters). If we use that as our standard to think about the impact of respiratory rate, you will see the following:

If you breathe at a respiratory rate of 12 breaths per minute (low end of normal), each breath would be 500 milliliters. With that in mind, for every 500-milliliter breath, 150 milliliters are used to bypass the trachea and 350 milliliters per breath, or 4,200 milliliters per minute, make it into the lungs where it can be used by the body.

6,000 ÷ 12 = 500 – 150 = 350

If you breathe at a respiratory rate of 20 breaths per minute (high end of normal), each breath would be 300 milliliters. With that in mind, for every 300-milliliter breath, 150 milliliters are used to bypass the trachea and 150 milliliters per breath, or 3,000 milliliters per minute, make it into the lungs where it can be used by the body.

6,000 ÷ 20 = 300 – 150 = 150

If you breathe at a respiratory rate of 40 breaths per minute (high), each breath would be 150 milliliters. With that in mind, for every 150-milliliter breath, 150 milliliters are used to bypass the trachea, and none of that makes it into the lungs where it can be used by the body.

6000 ÷ 40 = 150 – 150 = 0

Is it any wonder you feel so bad or that your oxygen plummets when you are panting like a dog trying to catch your breath? This highlights the importance of trying to take slow deep breaths using controlled breathing techniques, as described in Ultimate Pulmonary Wellness, such as pursed-lip breathing, diaphragmatic breathing, paced breathing, and recovery from shortness of breath methods for those “code red” situations.

This is always true, but even more so if you require supplemental oxygen because as you can see from the above, regardless of what device you use or what setting or liter flow you have it on, if you are breathing at 40 breaths per minute, it’s not going to do you much good because the oxygen won’t get into the lungs where you can use it. And this is especially, especially true in the case of a pulsed-delivery system. Don’t stop the breath as soon as you hear the device trigger. Breathe deeply so that the oxygen makes it into the lungs where your body can use it.

As an adjunct to the above techniques, try this “Donna Frownfelter Special,” which should help you to decrease your respiratory rate and give you greater control of your breathing. Take a short pause (one to two seconds) at the top of inspiration and at the end of exhalation. To be clear, this should not be a breath-holding maneuver, just a slight inspiratory and expiratory pause.

And here is an additional pearl from chest physical therapist extraordinaire, Marion Mackles. During exhalation, instead of just trying to blow the air out or allowing the air to escape gently through pursed lips, place your hands on your knees with your elbows out (bulldog position), and allow your body to slowly collapse forward as you sigh out through pursed lips. As you start to inhale again, push up gently on your arms as you return your upper body to the upright position. By folding the thorax over the abdomen like an accordion, the increased pressure from the abdominal contents assists in expelling the air from your lungs and helps in setting up your next inhalation.