- Critical Care Associates
Shea, M.D., F.C.C.P.
Blood oxygen levels can vary from day to day
depending upon your lung condition and other medical problems. In the hospital setting,
oxygen measurement is often done on several occasions when someone is quite ill. For home
oxygen, measurement is often is made after recovery from any acute medical problem when
medical treatment is stable and no infection is present. The amount of oxygen is expressed
as a flow rate, in liters per minute (usually between one and four liters per minute). It
will also be recommended the number of hours per day during which the oxygen should be
Taking arterial blood, usually from an artery in the wrist does measurement of blood oxygen. If the oxygen level (PO2) or the oxygen saturation is low, home oxygen may be prescribed. A repeat blood sample may also be taken while oxygen is being given.
Who Benefits? Oxygen is an essential part of life. Normal healthy people usually have a blood oxygen level above 85 units (mmHg). In people with lung problems, the level may fall to low levels even though the body can continue to perform normally. When oxygen levels fall below 55-60 units, added oxygen may be helpful. Chronic obstructive pulmonary disease (COPD) is the term used most commonly to describe smoke-related conditions such as emphysema and chronic bronchitis. Patients with these problems may have severe shortness of breath with a normal oxygen level. In the later stages of COPD, low oxygen levels become more common. Supplemental oxygen in patients with severe COPD and low oxygen levels of 55-60 units or below, prolongs life and in some cases also improves the quality of their life. Patients who use their added oxygen for 24 hours a day show a longer life span than those who use it for 15 hours; and these people in turn do better than those who use it only during sleeping hours.
The same criteria are used for giving oxygen to people with other diseases such as cystic fibrosis and pulmonary fibrosis. Oxygen may also be used for relief of breathlessness in patients who have lung cancer when the blood oxygen is low. Oxygen is supplied for emergency use to patients who have had severe acute life-threatening attacks of asthma, or for severe angina heart disease when these patients have a low oxygen level, when maximal medical treatment has been given and heart surgery is not possible.
Does Oxygen Help Every Cause of Breathlessness?People with lung disease suffer from shortness of breath, particularly on physical exertion. In some cases this may mean a low blood oxygen level, but there are many other causes of breathlessness. These include fatigue of the breathing muscles, fluid on the lungs, blockage of the airways (mucus, sputum). Many patients notice that they have received oxygen for treatment of shortness of breath while being in the hospital. This has generally been combined with other treatments for the underlying causes of shortness of breath. The fall in blood oxygen, which may occur during a flare-up of a lung condition, improves after treatment, and in many cases further oxygen is not required.
Although the use of oxygen in these cases may also relieve shortness of breath, in many cases it does not. It is important to know that the reason for giving oxygen in COPD is to improve quality of life and not to relieve shortness of breath.
Many people with lung disease feel short of breath during physical exertion, but not all will have a fall in their oxygen levels. To find out if your blood oxygen falls with exercise, the oxygen level is measured at rest, and then during exercise. The amount of exercise you can perform and the level of oxygen at the end of exercise when breathing room air is then compared with that while breathing oxygen. Some people definitely benefit from oxygen during exertion. If a benefit is demonstrated, it is recommended that you use your oxygen "as needed", which means during any activity which normally causes you to become short of breath. If no benefit is demonstrated with oxygen, remember that there are many other causes of breathlessness besides a low oxygen level.
How Is Oxygen Given?The most common method for home oxygen delivery is the oxygen concentrator. It is about the size of a TV and is an electrically driven machine that concentrates oxygen from the air through a fine sieve (mesh). Electricity is used for many hours in the day from a standard power outlet. These machines provide the amount of oxygen needed to reverse the low blood oxygen levels. They do not remove oxygen from a room any more than an adult would by simple breathing from the same room air. Cost rebates may be available through your local electricity supplier if you are a pensioner or a veteran.
Added oxygen is usually delivered into the nose through soft plastic prongs attached to tubing which fits onto the outflow port of the concentrator. Long lengths of tubing are also available to allow you to move around your house more freely while wearing the prongs. Nasal prongs also enable you to use your oxygen while eating or drinking.
Most people have no problems with nasal prongs. Occasionally some people may notice discomfort or drying of the nasal membranes, but this can be improved by applying a water-based lubricant (NOT OIL-BASED) to the nose several times per day. At the most common flow rates (up to 4 liters per minute), added water humidification is not usually required to keep the nose moist. If needed, humidification can be added by using a "bubble bottle" containing water, through which oxygen is bubbled.
People whose exercise capacity is increased a lot by additional oxygen benefit from lightweight portable oxygen cylinders or liquid oxygen. They are available in a holder with wheels. Even smaller cylinders may be carried in a holster over the shoulder, or in backpack. In order to get these small cylinders to last longer before needing a refill, they are generally fitted with a conservation device. These simple battery-operated devices control the flow of oxygen from the cylinder to the nasal prongs. They conserve oxygen be delivering a short pulse of oxygen only when breathing in, rather than continuously as with normal oxygen supply systems. This keeps oxygen from being wasted while breathing out. This prolongs the time each oxygen cylinder lasts by at least 3 to 5 times.
Larger oxygen cylinders are also provided in the home to serve as back up to the concentrator in case of mechanical or power failure for those requiring oxygen 24 hours a day.
Oxygen SafetyOxygen use in the home is safe. Oxygen does not explode; however, it does support combustion.
This means that you must not smoke while wearing oxygen, and you should not wear your oxygen while close to gas stoves, lighted fireplaces, or any other sources of heat or open flame. There have been cases where nasal prongs have caught fire as the wearer was smoking during oxygen use.
Traveling With OxygenThe oxygen concentrator is transportable and may be taken in the car if you are planning to be away from home for any long periods of time. It must remain in an upright position and may be carried in the trunk of you vehicle (if large enough), or standing up on the back seat, with a rear seat belt to hold it in place. Keep your oxygen cylinders secured in your vehicle (not rolling around). Some airlines and buslines will carry concentrators, so check before traveling. Safety regulations forbid the use of patients own compressed oxygen equipment in flight. However, airlines can provide such equipment and arrangements are in place to encourage people with lung disease to carry out air travel.
SummaryThere are many positive benefits from home oxygen treatment. Most people report that with a few changes to their lifestyle, a good quality of life can be maintained. Complaints including "being addicted to oxygen", "being tied to a machine", and "living on the end of a plastic tube", prove to be quite wrong. When compared to being in the hospital, living at home with added oxygen treatment allows control of daily life and generally improves the way people feel.
With the increasing use of portable oxygen equipment, we now see more people out and about at the shops, theatre, or simply walking the dog; people who would otherwise be frightened to leave their front door.
The use of long lengths of tubing at home with the concentrator close to the external doorway allows time in the garden or simply sitting outside.
Most people find being "self-conscious" with oxygen equipment is short-lived, and once confidence improves the positive benefits quickly outweigh any embarrassment.