(See also Overview of Pulmonary Rehabilitation.)
Some people with chronic lung disease need only a brief period of oxygen therapy during an acute flare up (exacerbation) of their lung disease. Others, in whom oxygen levels in the blood are consistently low (such as people with cystic fibrosis or alpha-1 antitrypsin deficiency), may require oxygen therapy on a daily basis. In these people, oxygen use increases survival time. The more hours a day the oxygen is used, the better the result. People survive longer when 12 hours of oxygen are used than when no oxygen is used. People survive even longer when oxygen is used continuously (24 hours per day). Long-term oxygen use decreases shortness of breath and reduces the strain on the heart that lung disease causes. Both sleep quality and the ability to exercise tend to improve.
Some people with chronic lung disease have low levels of oxygen only when they physically exert themselves. These people can limit their oxygen use to periods of exertion. Other people have low oxygen levels only when they are sleeping. These people can limit their oxygen use to overnight hours.
Once the critical level of oxygen is determined, oximetry may be used to adjust oxygen flow settings (how much oxygen the person needs per minute) over time. Oximetry is painless and uses a simple device that is attached to a finger or ear to measure the concentration of oxygen in the blood.
Oxygen for long-term home use is available from three different delivery systems:
An oxygen concentrator is an electrically powered device that separates the oxygen from the nitrogen in the air, allowing a person with lung disease to receive purified oxygen. Because the system pulls oxygen from the room air, the person does not need to receive deliveries of oxygen. Although many of the devices also operate by battery as well, people should have a supply of oxygen available in case of a power or battery failure.
With a liquid oxygen system, oxygen is stored as a liquid under very cold conditions. As the oxygen is released, it turns back into a gas, and the person can breathe it in.
With a compressed gas system, oxygen is stored in a metal tank under pressure and is released as the person breathes in.
Inside the home, liquid and compressed gas systems use large tanks to store oxygen. These tanks are periodically refilled by a home care company. Small, portable tanks of compressed or liquid oxygen or a portable oxygen concentrator may be used outside the home. Each system has advantages and disadvantages.
Oxygen sources should be closed tightly when not in use. Because oxygen is flammable and can cause an explosion, it is also important to keep tanks away from any sources of ignition, such as matches, heaters, or hair dryers. No one in the house should smoke when oxygen is in use.
Oxygen is typically administered through a two-pronged nasal tube (cannula) with either continuous flow or a demand-type system. To improve efficiency and increase mobility in people requiring high amounts of supplemental oxygen, several devices, including reservoir cannulas and transtracheal catheters, can be used.
When a person exhales, a reservoir cannula stores oxygen in a small chamber, and then returns the oxygen when the person inhales.
Demand-type systems deliver oxygen only when triggered by the machine's user (such as when a person inhales or presses on the device). They do not deliver oxygen continuously. Some have small reservoirs.
A transtracheal catheter is a small tube that is inserted through the skin directly into the windpipe. Oxygen is then delivered directly to the windpipe. Usually, a respiratory therapist or physician instructs the person about proper oxygen use.