Oxygen is quintessential for our being. When one has a respiratory condition and breathing is adversely affected, a doctor prescribes supplemental oxygen to aid the oxygen intake. When we think of supplemental oxygen solutions, a traditional bulky oxygen tank often comes to the mind. Nonetheless, oxygen delivery technology is ever evolving and has made several advances in the last few years. The two widely used oxygen delivery mechanisms at home are oxygen tanks and oxygen concentrators. We’ll discuss below what they are and how they differ so that you can make an informed decision about your choice of oxygen delivery.
How Do Oxygen Tanks Work?
Oxygen tank is the most prevalent way to deliver medical-grade oxygen to the patients. Oxygen tanks or cylinders are generally made of steel or aluminum. There are two kinds of oxygen tanks – one contains compressed oxygen, and another contains liquid oxygen.
The oxygen is extracted from the air and compressed at a very high-pressure of 2,200 PSI to be stored in tanks. Since these tanks are high pressured, the oxygen is delivered through a regulator to maintain the required oxygen flow rate.
Whereas to create liquid oxygen, the gaseous form of oxygen is cooled at -297°F. It is stored in special vacuum insulated containers to maintain the liquid state of the oxygen. Liquid oxygen takes up significantly less amount of storage space. One liter of liquid oxygen is equivalent to 860 gaseous liters. When the liquid oxygen is exposed to the room temperature it quickly converts to its gaseous form, ready to be consumed.
Per the United States Pharmacopoeia (USP) standards, oxygen tanks or cylinders must not have less than 99% oxygen purity. Usually, the compressed oxygen and the liquid oxygen are stored at a 99.5% purity level.
How Do Oxygen Concentrators Work?
Oxygen concentrators (or oxygenators) differ significantly from traditional oxygen tanks since they do not store oxygen. Regular air is made up of 78% nitrogen, 21% oxygen and 1% other gases. An oxygen concentrator receives the ambient air, filters out nitrogen to retain oxygen, and then supplies it through the nozzle. Oxygen concentrators are usually capable of delivering 90 to 95 percent pure oxygen.
They deliver air in a continuous or intermittent flow. Continuous flow oxygen concentrators provide a consistent amount of oxygen regardless of how many times a patient breathes per minute. In contrast, intermittent flow (also known as pulse flow) delivers oxygen in periodic air bolus. Pulse-flow capable oxygen concentrators detect the user’s breath and deliver oxygen right when they inhale.
Size and Weight
Oxygen cylinders and tanks vary in size and capacity. The commonly used E type cylinder can deliver 680 liters of oxygen when full (at 2015 PSI). With this capacity, the tank is capable of delivering oxygen for over five hours at a flow rate of 2 liters per minute. This cylinder is over two feet in length and weighs almost 8 pounds.
The most critical factor that determines which size of an oxygen tank to go for is the user’s oxygen requirement. On a high oxygen flow requirement, H or M250 tanks are advised. These large tanks are stationary and weigh around 120 pounds.
In the case of liquid oxygen, specially designed oxygen reservoirs are required since oxygen in liquid form is very cold. A nasal cannula can be hooked to the reservoir to fulfill the oxygen need at home. The liquid oxygen reservoirs are big and not mobile. Besides, liquid oxygen can be delivered at a higher rate of flow for a much longer period than a compressed gas system. However, liquid oxygen is much more expensive than gas.
Portable Oxygen Concentrators are considerably small and light. The smallest portable device is Inogen One G4 and it weighs 2.8lbs only. At a setting of 2, it can last over 4 hours on a double battery. These devices are made by keeping in mind the active lifestyle needs of the patients.
Home oxygen concentrators are meant for in-house usage and can provide oxygen at up to 10 liters per minute on a continuous flow. Therefore, these devices are larger than portable oxygen concentrators and weigh around 30 pounds. Nevertheless, they have wheels at the bottom and can be moved easily to any room in your house. These units are as loud as a humming refrigerator. If it bothers you, the device can be set up in a separate room with a length of tubing that allows the patient mobility around the home.
Oxygen tanks such as type A, B, C, D, JD, and E are portable. They can be carried around in and out of your house. Some of these tanks come with a cart to carry around.
Liquid oxygen can be used outside the house with the help of a portable liquid oxygen container. Liquid oxygen can be transferred to this smaller container from the storage tank. Many of these smaller portable containers can deliver oxygen for up to 10 hours, depending on the capacity and consumption.
Portable oxygen concentrators (POC), as the name suggests, are highly portable. They run on battery and make their own oxygen, so they can be taken anywhere. Of course, not in water and at extreme temperatures. POC comes with a DC charger that means you can charge the unit in your car, RV, or boat using the cigarette lighter. POC can be slid into a messenger-bag style carrying case or carried around in a tailor-made backpack or a cart.
Not only that, portable oxygen concentrators are TSA and FAA approved, allowing them to be used on a flight. They are allowed on airplanes as long as they are FAA approved, have sufficient battery, and can fit under a seat or in an overhead compartment. Oxygen concentrators can be rented for travel use.
Flying with a Portable Oxygen Concentrator
Oxygen tanks need to be refilled or exchanged from the provider weekly or biweekly, depending on the consumption. This not only means you have to be at the home when the provider visits but also that it’s a recurring expense.
Home Oxygenators do not require refilling. This is a major advantage because the user doesn’t have to be concerned with changing the tank when the oxygen runs out. They do, however, require a power source. Learn how much a concentrator add to your electricity bill. Patients who require continuous oxygen or a high flow rate will find concentrators advantageous because they never run out of oxygen.
Portable oxygen concentrators also do not require refilling or calling the provider regularly. You don’t have to be home at a fixed time or worry about carrying the tanks in and out. POCs are battery-powered and come with adapters so that they can be plugged into an AC or DC power source when the battery is low.
Some Other Important Points
Compressed Oxygen Tanks
- Oxygen tank needs to be handled with care and kept upright
- Oxygen tanks have to be changed multiple times in a day, when empty
- The pressure valve attached to oxygen tanks must be checked consistently
- Pressurized oxygen is a fire hazard and appropriate measure must be taken for safe storage
- Like gas, liquid oxygen containers need to be kept level
- The bottle attached to the reservoir to collect condensed water needs to be emptied regularly
- When mishandled while filling the portable tank, it can cause frostbite burns to the skin
- Oxygen concentrators feature several alerts to make sure you get the required oxygen
- They are more expensive up-front but in the long term they cost less than oxygen tanks
When choosing between a traditional oxygen tank and oxygen concentrator, there are many things to take into consideration. These include how much oxygen the patient has been prescribed, how often he or she will leave home and what types of activities will be engaged in. You should also consider how much the unit weighs and balance that with personal strength so that the oxygen tank or concentrator can be moved with ease when necessary. Finally, you may want to choose a system that can grow with you if you anticipate that your oxygen needs may increase in the future.
- How Does an Oxygen Concentrator Work?
- 11 Critical Safety Precautions For Oxygen Therapy
- Pulse vs. Continuous Flow
Updated: March 18, 2020
Published: May 11, 2016