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Why Do I Need Oxygen Therapy?

To answer the questions about why you might need oxygen you need to understand what oxygen is, what it does in your body, who needs it in general and many other questions that will be answered on this webpage.

What is oxygen?

Air is a mixture of gases. Oxygen and nitrogen are the two main gases in the air we breathe. Oxygen accounts for about 21% of gas in air. The abbreviation for oxygen is O2. Every cell in our body needs oxygen to live. In order for oxygen to get to these cells, it must be transported through the airways of the lungs. If there is a blockage in the airways from mucus or narrowing of the airways from swelling or constriction, air may not reach enough alveoli to deliver oxygen. In some COPD patients, adequate air is brought into the alveoli, but the oxygen contained in the air is not able to pass into the capillaries surrounding the alveoli. This results in low oxygen levels and is called hypoxemia. By breathing even small amounts of additional oxygen, the oxygen level in the air rises above 21% to 23 or 24%. This small amount is enough to help "push" the oxygen into the capillaries. Since the body cannot store oxygen, oxygen needs to be given whenever the body is low on oxygen. In some instances, this means that the COPD patient must use oxygen 24 hours a day. The need for continuous oxygen is called long term oxygen therapy (LTOT). Oxygen therapy is important to understand because oxygen is not useful for everyone with COPD. In fact, oxygen is probably one of the least understood and misused therapies for people with COPD.

How do I know I need oxygen?

The need for oxygen is found by measuring the amount of oxygen in your blood stream. If your oxygen level is below a critical level at rest, then you need oxygen close to 24 hours a day. Some people with COPD do not need oxygen when they are inactive, such as when sitting, but need oxygen when exercising, such as walking, or with eating and/or sleeping. Breathlessness is not a reliable way of determining if you need oxygen. Sometimes, you can be very short of breath and not need oxygen; other times your breathing may feel okay, but you are not getting enough oxygen. Oxygen is not given to treat breathlessness. Although some patients feel some relief in their breathlessness from the flow of oxygen on their face, less expensive ways of getting this same relief can be obtained with a fan.

Your healthcare provider will find out if you need oxygen therapy by taking a blood sample from your artery. This test is called an arterial blood gas (ABG) and it measures carbon dioxide and pH in addition to oxygen. This can be done in the office, clinic or hospital, wherever the arterial blood equipment is available. When making an important decision, such as who needs oxygen, the best evaluation is with an ABG. Measuring oxygen levels can also be done with a pulse oximeter. Oximetry is performed by attaching a clip to your finger that shines a light through it. A tiny computer in the oximeter then determines your oxygen level by the color of the light that shines through from the other side. Oximetry only measures one characteristic of the oxygen in your body and, since it is not as precise as an ABG, should only be used as a guide to oxygen therapy.

How much oxygen should I take?

Oxygen is a medication prescribed by your healthcare provider. Optimally, the amount is carefully decided based on an ABG and then guided by oximetry. Once the amount of oxygen you need is decided, your provider will advise you of the rate at which the oxygen should be set. It is very important that you only use the amount that your doctor or nurse has prescribed, no more or no less. The treatment goal is to keep your oxygen at a level that meets your body’s need for oxygen, usually above 89%. Taking too much oxygen sends a message to your brain to slow your breathing. Whereas too little may deprive the tissue in your brain and heart of oxygen and result in memory loss or changes in your heart.

How many hours a day will I need oxygen?

In some cases, you may only need to use oxygen when you are exercising or sleeping. However, in most cases, oxygen should be used as close to 24 hours a day as possible. If your oxygen level is found to be low, using less than 15 hours a day has not been shown to provide a benefit, and does not protect your heart, brain and other organs of the body. If you are instructed to use continuous oxygen and choose to go off oxygen temporarily, it is best to do so only while resting quietly, not while sleeping, walking or exerting yourself.

During exercise you use more energy and therefore need more oxygen. To find out how much oxygen is needed during exercise, an exercise stress test or a timed walk test is usually done. It is important that the test be performed while using the type of delivery device that is going to be used at home.

The immediate benefits of using oxygen during exercise may be relief of breathlessness (also called dyspnea) and an improvement in your ability to walk or do activities.

Will I need oxygen when I sleep?

During sleep, you slow down your breathing. People have low oxygen levels while awake are usually also lacking oxygen during sleep. In some cases, people that may not require oxygen while awake may require extra oxygen while sleeping. Your healthcare provider will determine if and how much oxygen you should take at night. Your needs may be determined by using an oximeter that will record your oxygen level while you sleep in your home or you may be asked to sleep at a sleep laboratory.

What kind of devices provide oxygen?

There are several types of oxygen devices. The type of device you are given will depend on where you live and on the purpose of your oxygen. Oxygen can be delivered by three types of devices: oxygen concentrator, liquid system or oxygen in a metal cylinder.

What are oxygen concentrators?
 A concentrator draws in air from the room/environment (which contains 21% oxygen) and passes the air through a special filter collecting only the oxygen into a reservoir. When the machine is turned on, this process of collection takes place. The reservoir and the concentrator have limited storage, so virtually all the oxygen saved is released into the oxygen tubing for delivery to the patient. The concentration of oxygen delivered by a concentrator is 90-95%. The concentrator is run by electricity. The concentrator weighs about 50 pounds (23 kg) and is usually on wheels so that it can be easily moved in the home from room to room. The machine should be located where there is good circulation and away from furniture and walls. There is a compressor inside the machine that makes a regular noise that can be distracting to some. The device is not intended to be portable, however, recently, a new type of concentrator has been developed that makes it possible to fill portable cylinders from a concentrator. Also in development is a concentrator that weighs less than 10 pounds (5 kg) and runs off of a battery.

What maintenance do oxygen concentrators require?
Concentrators have an air inlet and a filter in front of the air inlet. Make sure that the air inlet is not covered and that it allows fresh air into the concentrator. This filter should be washed once a week in dishwasher detergent. After washing it should be thoroughly rinsed and completely dried before re-inserting. The instruction manual will outline how many filters your concentrator has and how often each of these should be changed. Your concentrator should be serviced after approximately 10,000 hours of use or annually. At that time it should be checked to assure that it is producing the right amount of oxygen. Improper maintenance may result in low concentrations of oxygen being delivered.

What is liquid oxygen?
Liquid oxygen is oxygen that is cooled to -183° C (-297°F), at which point it becomes a liquid. When in liquid form, the oxygen takes up much less room and can be stored in specially designed containers. The concentration of oxygen delivered from liquid oxygen is 100%.  Most hospitals use oxygen in liquid form. The gas molecules in the container are in constant movement, allowing for the liquid to slowly turn into a gaseous form. This results in a build up of pressure in the container, which is either delivered to the patient or released by a ventilation valve. Liquid oxygen is stored in the home in large storage reservoirs. The patient uses a smaller tank to fill for portability. You will need to be instructed on how to fill the smaller tank from the larger storage tank. Your oxygen delivery service will routinely fill the larger tank, every 1-2 weeks, depending on the flow rate you use.

What maintenance do liquid oxygen devices require?
The stationary tank should be placed on a level surface so there is minimal chance of the tank tipping. Little maintenance is required. If a bottle is attached to the tank for collecting condensed water, it must be emptied and cleaned regularly. The outside of the tank can be cleaned with a damp cloth when necessary. In addition to instructions for transferring the oxygen from the large tank to the smaller tank, instruction should be received in what should be done if any part of the system should freeze.

What are oxygen cylinders?
 This is the oldest method for delivering oxygen. Oxygen is compressed into a steel cylinder under high pressure, often a pressure of about 200 atmospheres. Like liquid oxygen, the concentration of oxygen delivered from cylinders is 100%. Oxygen is stored in large or small cylinders. Large cylinders are very heavy and have to be changed often as the contents are quickly used. Smaller cylinders are therefore emptied more quickly than larger cylinders, but are portable. Smaller aluminum cylinders are also available for portability. When using oxygen-sparing tubes or oxygen-conserving devices, these small cylinders can last for up to 8 hours. The small cylinders are usually used for portability when an oxygen concentrator is the main source of oxygen in the home.

What maintenance do oxygen cylinders require?
The pressure valves must be checked frequently. When the cylinders are empty, the regulator must be removed and placed on a full cylinder.

What about hoses or tubes attached to the oxygen device?

The main tubing attached to the different systems can be up to 15 meters/50 feet long to allow for mobility. The length of the tubing should only be as long as necessary in order to be mobile, for example long enough to get from one end of the house to the other. Having excess tubing may become a hazard to yourself and others. Long tubing also increases chances of knotting and cutting off the flow of oxygen. The tubes should be changed every 6-12 months. The tubing must be the right dimension. The inner diameter should be at least 5 mm to ensure the resistance is minimal.

What is a nasal cannula?
A nasal cannula is a dual-pronged tube attached to the oxygen device for delivering oxygen through the nose. These tubes come in different sizes and lengths. Make sure that the one you have fits you well. The typical length of the tubing is about 2 meters (6 feet). The nasal cannula should be changed approximately once a month due to the plastic nasal cannula becoming hard and stiff. The part of the cannula that is situated in the nose may be washed and the rest of the cannula may be wiped with a damp cloth.

What are oxygen sparing/conserving devices?
Oxygen-sparing/conserving devices are devices used to reduce the amount of oxygen needed from the oxygen source (liquid, concentrator or cylinder). These devices improve the efficiency of the delivery of oxygen, reducing the amount of oxygen that is used. This is accomplished by increasing the flow of oxygen on inhalation and limiting the flow of oxygen on exhalation. By increasing the delivery of oxygen when you breathe in, and reducing or stopping the delivery when you are breathing out, less of the oxygen is wasted. This makes it possible to use smaller and lighter ambulatory systems or standard systems. In addition, the delivery systems (liquid or cylinders) last longer. There are three types of oxygen-sparing/conserving devices: the on-demand device, reservoir cannula and transtracheal oxygen.

What is an on-demand device?
On-demand oxygen delivery devices deliver a small amount of oxygen, usually when you begin to take a breath in through your nose. The delivery device is connected to the oxygen source by the nasal cannula. The device senses the start of inhalation (through the nasal cannula) and immediately gives a short pulse of oxygen.

Nose congestion and mouth breathing may make it hard for the delivery device to sense inhalation. If the level of inspiration through the nose is very low, no oxygen may be delivered. Some types of devices have an alarm that goes off if no breathing activity is detected. Most of the on-demand devices are battery driven and the batteries need to be replaced every couple of weeks.

What are reservoir cannulas?
A reservoir cannula operates by storing oxygen in a small chamber. Storage of oxygen takes place while you are breathing out. This stored oxygen is available when you breathe in. This may allow you to require lower oxygen flow rates while still receiving the same amount of oxygen. There are two types of reservoir devices, the Oxymizer and the Pendant Oxymizer. The differences in the two devices are the location where the storage chamber is located.

What is transtracheal oxygen?
Transtracheal oxygen is oxygen delivered through a catheter placed directly through the neck into the trachea (windpipe). Delivery of oxygen directly into the trachea provides higher amounts of oxygen to be delivered because little is wasted. Flow rates of oxygen can often be reduced by close to 50% at rest and 30% during exercise, as compared with oxygen delivered via a standard nasal cannula. A cosmetic advantage of transtracheal oxygen therapy is that the tubing is not as visible as with standard devices.

Not everyone is a candidate for transtracheal oxygen delivery (TTOD). Candidates must be evaluated, educated and monitored by a trained team of healthcare providers. Complications from TTOD are not frequent, but can be serious.

Do I need a humidifier on my oxygen system?

If you use transtracheal oxygen, humidification of the oxygen is important. With other delivery systems at less than 4 liters per minute, humidification is not usually necessary or beneficial. If you have dryness in your nose, you can use a saline (salt water) spray. If this does not help, a humidifier can be attached to the oxygen system. The humidifier is a bottle filled with sterile or distilled water. The oxygen passes through the water to gather moisture. Water from the humidifier should be changed every 1-2 days.

What should I watch for while I am on oxygen?

In some cases too much oxygen may lead to an increase of carbon dioxide in your blood. This can give symptoms like drowsiness and difficulty keeping awake. Receiving too much oxygen while sleeping can also result in a morning headache. A sign of receiving too little oxygen is a general feeling of fatigue. If any of these problems occur, contact your healthcare provider.

What safety precautions should I use when on oxygen?

Oxygen used properly is safe. DO NOT SMOKE NEAR OXYGEN! Also, stay away from open flames. It is important that no oil or grease is used on any of the oxygen equipment. Oxygen cylinders should be secured and placed in an area where they will not fall. Cylinders are under high pressure and a crack in the cylinder can be lethal. Remember to turn off all equipment when not in use. Oxygen containers should not be stored near water heaters, furnaces, or other sources of heat or flame. Oxygen containers and the storage room should be properly marked/labeled. There should be good ventilation around oxygen equipment. Your oxygen supplier should provide you with a complete list of instructions and safety precautions.

Do I have to worry about oxygen exploding or burning?

  • Oxygen alone will not explode and does not burn but oxygen will feed a flame.
  • Keep oxygen at least 2 meters or 6 feet away from an open flame.
  • Do not smoke while using oxygen, as clothing and hair can easily be ignited.
  • Stabilize all cylinders by placing carts in a safe area or by securing them to a wall.

In case of an accident what should I do?

In case of fire, evacuate immediately. Contact the fire department. Understand your oxygen system and what you need to do if there is a problem. Also, you should always have emergency telephone numbers in a central location, such as on the refrigerator. Emergency numbers should include 911 (or country code), your healthcare provider and your oxygen supplier.

Can I travel with oxygen?

It is safe to travel with oxygen, however, various transports have different regulations about their use with oxygen. Contact the appropriate business (airport, boat, train, bus) about their regulations well in advance of travel. Make sure that you have plenty of oxygen with you in case of delays or emergencies. Carry the contact numbers of your healthcare provider and oxygen supplier; you never know when you might need them. General information is listed below. More specific information on traveling with oxygen is available at www.oxygen4travel.com.

When traveling by car, oxygen equipment must be fastened securely in an upright position so that the equipment is stable during the trip.

When traveling by boat, ferry, train or bus take the same considerations as traveling by car. Contact the boat, ferry, train or bus company a few weeks before traveling to find out which rules apply.

When traveling by plane you should plan your trip weeks in advance and inform the airline and check their regulations. Obtain an oxygen prescription from your doctor that provides your diagnosis, your present condition, a statement that it is safe for you to travel and your oxygen prescription. Your oxygen company can help to arrange for oxygen at the airport and travel destinations. You should book a direct flight for several reasons: some airlines charge for oxygen by each leg of the trip, you will be off oxygen during part of your layover and travel is much less tiring when you do not have to make a connection. Make sure you keep a copy of your oxygen prescription, medication prescriptions, know the health facilities and healthcare providers at each travel destination, and take extra medicines on the plane with you, Your oxygen company can be a great source of help for travel.


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