Portable Oxygen: A User's Perspective

Options for the Active High-Flow User

Portable Oxygen: A User's Perspective

Options for the Active High-Flow User

The information here provided is for educational purposes only and it is not intended nor implied to be a substitute for professional medical advice. Always consult your own physician or healthcare provider with any questions you may have regarding a medical condition.   

High-flow users belong to an exclusive club representing about five percent of all oxygen users. Users who require more than 4 Lpm are automatic club members.

Club members understand that they will not have access to any of the many nice inventions of the past decade. Manufacturers of portable oxygen equipment have focused their attention on the other 95 percent of users, leaving club members with the technology of the 1980s.

For this older technology, club members are charged no more than their low-flow counterparts are charged for the newer technology. My oxygen provider charges Medicare the same $96.00 a month that it charged when my flow rate was below 4 Lpm and I pay the same $7.19 per month copay. If you are not on Medicare, check with your insurance company. You may find they also do not discriminate against club members.

Club members are no different from other oxygen users. They live happy, active, and fun filled lives. Listen to what some club members have to say about their life styles.

Charlie from Illinois writes
Stay at home??  BS... I fish--I hunt-- I ride my ATV--I work my Weimaraner-- I visit friends in other states.--I shop with my better half--AND-- I am at 6 LPM  (10 LPM when doing strenuous activity).

Pete of Spotsylvania, VA writes
Most days are like today. I spent more than an hour at pulmonary rehab at the hospital followed by a dentist appointment. I serve my church as its Senior Warden during its $1.3M building program, am a board member of NHOPA, and am president of my homeowners' association.

My wife and I attend events in both Richmond and DC, each an hours drive away. We take RV trips at least twice a year. In May 2003 we will be on a 20-day trip that will take us through Oklahoma and Michigan. I do all the long distance driving.

Club members just need a lot of oxygen to enjoy their active life. For example, let's compare two users who use portable oxygen 8 hours a day. One is an 8 Lpm club member and the other a typical 2 Lpm user whose portable system includes a conserver.
  • The 2 Lpm user uses 14 E cylinders  (image) in a typical month, changing cylinders every other day.

  • The 8 Lpm user uses 170 E cylinders in a typical month, changing cylinders more than 5 times a day.
Club members have little in common with their low-flow user counterparts when it comes to oxygen equipment and supplies.  High-flow users need to be aware of the following.
  • pulse systems. There are no conservers, and therefore, no pulse systems with settings greater than 6. High-flow users prescribed 6 Lpm or more must use continuous flow from either compressed or liquid oxygen systems.
  • regulators. The regulator, some with settings from 0 to 15 Lpm and others with settings from 0 to 25 Lpm, replaces the conserver on both compressed and liquid oxygen systems.

  • cannulas. Cannulas are generally not recommended at flow rates of 6 Lpm or higher. Alternatives include a mask or a transtracheal catheter.

  •  liquid oxygen. For portable use, liquid oxygen is more efficient than compressed oxygen. Liquid oxygen is stored under less pressure (21 psi) than compressed oxygen (2,000 psi), meaning that liquid oxygen does not need the extensive and weighty physical protection that compressed oxygen requires. The liquid oxygen container is simply a thermos type container that minimizes warming and evaporation. 
The efficiency of liquid oxygen becomes clear when one compares the weight and duration of liquid and compressed oxygen. A liquid portable, which weighs about the same as an E cylinder, lasts a third longer. To better understand the relative merits of compressed and liquid oxygen, see Liquid vs. Compressed.
I have four liquid High-Flows (image) , manufactured by Caire. One gets me through a two-hour grocery shopping trip, two covers me for a doctor's visit, and four gets me through a day's visit to DC, a 60 mile drive away. Having been stuck in traffic on more than one occasion and having a full High-Flow once fail me, I carry a couple of  D cylinder with a regulator in the back of my minivan for such emergencies.

The source of liquid oxygen for my portables is three reservoirs (image) that sit in my garage and one in my minivan. Since I use about one each week, my provider comes by and fills them every three weeks. A fourth reservoir is my emergency backup to my concentrator.

When we had an RV,  we have a neighbor load my concentrator and or provider loaded a full  reservoir into it. I also take my portables. When the reservoir is nearly empty, we stop at an Apria branch ( Click here to see Apria's Great Escape program) where I have pre-arrange refill service at no cost to me.

Table 1 provides some of the basic information about four portable options for high-flow users--the D and E compressed oxygen cylinders and two high-flow liquid oxygen portables. In this table you see the following:
  • At 23 inches in length, an E cylinder is too awkward to carry.
  • The weight of a filled E cylinder is about the same as the weight of a liquid portable.
  • The gas capacity of a liquid portable is one and a half times that of an E cylinder.
  • At an evaporation rate of one pound a day, the oxygen in a liquid portable will deplete in three days.
Table 1
High-Flow Portable Systems

Oxygen System

Oxygen System



Puritan Bennett's
Companion T

Width & Depth
8 x 4.5'

5.3 lbs.
7.9 lbs.
6.5 lbs.
5.6 lbs.
6.5 lbs.
9.9 lbs.
9.5 lbs.
8.7 lbs.

1.23 L.
1.27 L
425 L
680 L
1,025 L
1,058 L
Evaporation Rate
1 lb./day
1.3 lb./day

Compressed Oxygen System
A high-flow compressed oxygen system requires a regulator. Typical of the regulators is American Healthcare's CGA 870 Pin Index regulator (image) available through your oxygen provider and from Med-WorldWide. Its yoke slides over the cylinder's neck where it is tightened with a T handle. It has a rotary positive click selection switch with 11 settings between 0 and 15 Lpm or, optionally, with settings between 0 and 25 Lpm.

At 6.5 lbs., a full D cylinder can be carried, but, because of its length (23 inches), an E cylinder cannot. Either can be pulled on a cart or transported in some other way. Your oxygen provider can provide you with carts for a single D or E cylinder (image) or two such cylinders (image). These carts weigh about 5 pounds each.

Liquid Oxygen Systems
The two portable liquid oxygen systems for high-flow users are the High-Flow (image) , manufactured by Caire Medical , and the Companion T (image) , manufactured by Puritan Bennett . Each weighs about 9 lbs. when full and has settings as high as 15 Lpm. Both systems have a cannula port, rotary selection switch, a contents gauge, and a carry strap.
  • The cannula port of the High-Flow is on the side. Both the selection switch and contents gauge are on the top, each under a separate covering lid. The selection switch has 11 settings from 0 to 15 Lpm. The contents gauge is electronic. Push its button and indicator lights tell you how much oxygen remains.
 NOTE. The indicator lights run on a 9 volt battery whose compartment is in the base of the tank. Replace the battery only when the tank is empty by turning it on its side and removing the two screws in its base to expose the battery compartment.

There is a warning light at one side of the gauge. When it flashes, it is time to replace the battery. I have rarely seen this indicator flashing. On two of my units,  when the gauge acted erratically, I replaced the battery and the gauge recovered and acted normally.
You, like I, may find it inconvenient to lift a lid each time you want to check the contents gauge or change the flow setting. This inconvenience can be easily remedied by removing the lids. Just remove two screws between the lids with an Allen wrench. Save the lids and screws in a plastic bag so they can be returned to your oxygen provider when you return the unit.
  • The selection switch of the Companion T is on the side. Both the contents gauge and the cannula port are on the top. The selection switch has 11 settings from 0 to 15 Lpm. The contents gauge which is very large and readable, operates like a spring-mounted fish scale. Lift the unit an inch or two above the floor by the front strap and the gauge's needle indicates the remaining contents.
The selection switches on both units are very similar.
  • The switches of both are in a small indentation of the unit, requiring the user to use fingertips to adjust the flow rate. Adjusting the flow rate could be a problem for those users with severe arthritis.

  • The selection numbers are visible when viewed directly above the switch. This is more difficult to do when the switch is located on the side, as it is on the Companion T.  Fortunately, the switches on both are positive click--that is, you can feel each new position as you turn the switch. Learn your settings by counting the clicks.
The High-Flow is a "side filler," meaning it is filled from the valve on the side of every reservoir, the same valve used to fill the reservoir. The Companion T is a "top filler," meaning it is filled while sitting on top of the reservoir, like the Helios™. Only Puritan Bennett reservoirs are top-fill equipped. Filling effort  favors the top filler slightly, but  not enough to be important in selecting one portable over the other. Those who carry a reservoir in a vehicle may choose the side-filler because there is insufficient headroom to fill a top-filler portable.

Both units have a carry strap so the unit can be carried over the shoulder. The Companion T is contoured, so it fits against your side. The High-Flow is not. The Companion T also has a shorter strap for carrying the unit in the hand.

Both liquid systems can be carried for short distances or pulled in a cart like the one used for the E cylinder. Because I need to sit and rest on walks of 10 yards or longer, I use a wheeled walker  which will carry two or three liquid portables and still give me a place to sit and rest.

In Table 2, shows the duration of the four systems of Table 1. Dual D cylinders vs. a single E cylinder is an option you might consider. You may find that dual Ds have several advantages.
  • Dual Ds on a cart have a lower center of gravity, making them easier to navigate than a single E cylinder.

  • An E cylinder cannot be easily transported on a wheeled walker, whereas, as many as four Ds can be so transported. Two D cylinders can be placed in the basket of the walker. Two more can be placed on the seat and secured with a shock cord, leaving half the seat for resting.
Notice that Table 2 shows that a pair of D cylinders last about 20 percent longer than an E cylinder--2.2 hours instead of 1.8 hours for the 6 Lpm user. As Table 3 shows, dual Ds weigh only 3 pounds more than an E cylinder. Consider dual Ds among your options.

Table 2
Duration Estimates (in hours)

Oxygen Systems
Oxygen Systems
Settings* (Lpm)
Dual D

Puritan Bennett's
Companion T

1.3 1.1
* All also have these settings: 0 (Off), 0.5, 1, 2, 2.5, and 3

The estimates shown in Table 2 assume normal operating conditions. Your results many vary for one of several reasons.
  • When left overnight, a liquid portable will lose about a half pound of its liquid (see the evaporation rate in Table 1), or as much as 1/6th of its contents.

  • If you, like me, set the regulator to 15 Lpm while walking and drop it to 4 Lpm when at rest, the High-Flow will have a duration of about 3.25 hours or less, depending on how far you walk.
Table 3 shows system weights under several configurations. Notice that the weights of the E cylinder and the two liquid portables are about the same. Compare the duration of these three at any flow rate shown in Table 2. You will discover that the liquid portables provide a third more oxygen for the same weight.

Table 3
System Weight (in lbs.)

Oxygen Systems
Oxygen Systems

Dual (2) D

Companion T

Weight, when filled

 If you would like to find a nearby liquid oxygen provider, you might try one of two national liquid oxygen providers. Both list their branches by state at their websites. One is Apria (1-800-647-5484), who advertises that they have a branch within 75 miles of your home, and the other is Lincare (1-800-284-2006).

If compressed oxygen works well for you, there is some good news. Currently, most
compressed oxygen is stored in aluminum cylinders (image) , but Luxfer Gas Cylinders has introduced new technology that will dramatically reduce the weight of your oxygen package.  Using space-age materials, Luxfer’s new carbon-wrapped composite cylinders (image) are just as strong and dependable as their aluminum counterparts, but much lighter in weight.  This type of cylinder is already being used with great success by firefighters, who need the lightest-weight breathing cylinder possible while doing strenuous work in smoke filled environments.  These ultra-lightweight cylinders can truly enhance the lifestyle of a high-flow oxygen user. 

If you are able to talk your oxygen provider into getting you carbon-wrapped cylinders, you can go to
  • Table 3 and cut in half the weight of the D and E cylinders. That's right, an E cylinder would weigh less than five pounds when filled.

  • Table 2 and increase the duration of D and E cylinders by a third. The carbon-wrapped cylinders are stronger and can be pressurize to 3,000 psi, a third higher than the 2,000 psi of the aluminum cylinders.
It is your job to convince your provider to get the composite cylinders and to give them to a high-flow user.

I am highly concerned about the safety of using an oxygen cart for transporting a single cylinder (image) or dual cylinders (image). I discuss oxygen carts above only because they are options. But understand they are options with safety issues. Please heed the following warnings.
  • If you physically cannot easily control a cart, don't use one.
  • Carts are not designed to be used on slopes or uneven surfaces.

  • Carts should not be used on stairs or in unpaved areas.

  • Pay attention to traffic when placing a cart in or removing it from your vehicle.
When a cart tips, one of two things can happen. The cart can hit and injure your leg. You canl injure your hand or arm while trying to keep it from falling. If you currently use a cart to transport your oxygen and are concerned about your safety, discuss other options with your physician and oxygen provider.

Consider the terrain you will be covering before you take a trip and have an alternate plan should trailing a cart be risky. At the very least, you should have smaller cylinders that you or a companion can carry.

Whether you use compressed or liquid oxygen, there are a few cautions about handling and storing oxygen containers.
  • Secure all cylinders and tanks in the vehicle when traveling.

  • Keep liquid oxygen tanks and reservoirs vertical.

  • Never transport oxygen containers in the trunk of a car.

  • Liquid oxygen containers vent and increase the oxygen concentration in the air around them. Always keep the space around these containers well ventilated. When traveling, keep a window slightly opened.

  • Do not permit smoking in a vehicle that is transporting oxygen.
For more information about safety, see Oxygen Safety.

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© 2003 Copyright 
Peter M. Wilson, Ph.D. 
Founder of PortableOxygen.org

You have permission to print this document for your personal use. You also have permission to print, copy, and distribute this document to oxygen users and their caregivers.

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