Oxygen may be classified as an element, a gas, and a drug. Oxygen therapy is the administration of oxygen at concentrations greater than that in room air to treat or prevent hypoxemia (not enough oxygen in the blood). Oxygen delivery systems are classified as stationary, portable, or ambulatory. Oxygen can be administered by nasal cannula, mask, and tent. Hyperbaric oxygen therapy involves placing the patient in an airtight chamber with oxygen under pressure.
The body is constantly taking in oxygen and releasing carbon dioxide. If this process is inadequate, oxygen levels in the blood decrease, and the patient may need supplemental oxygen. Oxygen therapy is a
Arterial blood gas test— A blood test that measures oxygen and carbon dioxide in the blood.
Atelectasis— Partial or complete collapse of the lung, usually due to a blockage of the air passages with fluid, mucus or infection.
Breathing rate— The number of breaths per minute.
Cannula— Also called nasal cannula. A small, light-weight plastic tube with two hollow prongs that fit just inside the nose. Nasal cannulas are used to supply supplemental oxygen through the nose.
Cyanosis— Blue, gray, or dark purple discoloration of the skin caused by a deficiency of oxygen.
Ductus arteriosis— A fetal blood vessel that connects the aorta and pulmonary artery.
Flow meter— Device for measuring the rate of a gas (especially oxygen) or liquid.
Hypoxemia— Oxygen deficiency, defined as an oxygen level less than 60 mm Hg or arterial oxygen saturation of less than 90%. Different values are used for infants and patients with certain lung diseases.
Oxygenation— Saturation with oxygen.
Peak expiratory flow rate— A test used to measure how fast air can be exhaled from the lungs.
Pulmonary function tests— A series of tests that measure how well air is moving in and out of the lungs and carrying oxygen to the bloodstream.
Pulmonary rehabilitation— A program that helps patients learn how to breathe easier and improve their quality of life. Pulmonary rehabilitation includes treatment, exercise training, education, and counseling.
Pulmonologist— A physician who specializes in caring for people with lung diseases and breathing problems.
Pulse oximetry— A non-invasive test in which a device that clips onto the finger measures the oxygen level in the blood.
Residual volume— The volume of air remaining in the lungs, measured after a maximum expiration.
Respiratory failure— The sudden inability of the lungs to provide normal oxygen delivery or normal carbon dioxide removal.
Respiratory therapist— A health care professional who specializes in assessing, treating, and educating people with lung diseases.
Total lung capacity test— A test that measures the amount of air in the lungs after a person has breathed in as much as possible.
Vital capacity— Maximal breathing capacity; the amount of air that can be expired after a maximum inspiration.
key treatment in respiratory care. The purpose is to increase oxygen saturation in tissues where the saturation levels are too low due to illness or injury. Breathing prescribed oxygen increases the amount of oxygen in the blood, reduces the extra work of the heart, and decreases shortness of breath. Oxygen therapy is frequently ordered in the home care setting, as well as in acute (urgent) care facilities.
Some of the conditions oxygen therapy is used to treat include:
- documented hypoxemia
- severe respiratory distress (e.g., acute asthma orpneumonia)
- severe trauma
- chronic obstructive pulmonary disease (COPD, including chronic bronchitis, emphysema, and chronic asthma)
- pulmonary hypertension
- cor pulmonale
- acute myocardial infarction (heart attack)
- short-term therapy, such as postanesthesia recovery
Oxygen may also be used to treat chronic lung disease patients during exercise.
Hyperbaric oxygen therapy is used to treat the following conditions:
- gas gangrene
- decompression sickness
- air embolism
- smoke inhalation
- carbon monoxide poisoning
- cerebral hypoxic event
Helium-oxygen therapy is a treatment that may be used for patients with severe airway obstruction. The combination of helium and oxygen, known as heliox, reduces the density of the delivered gas, and has been shown to reduce the effort of breathing and improve ventilation when an airway obstruction is present. This type of treatment may be used in an emergency room for patients with acute, severe asthma.
Oxygen delivery (other than mechanical ventilators and hyperbaric chambers)
In the hospital, oxygen is supplied to each patient room via an outlet in the wall. Oxygen is delivered from a central source through a pipeline in the facility. A flow meter attached to the wall outlet accesses the oxygen. A valve regulates the oxygen flow, and attachments may be connected to provide moisture. In the home, the oxygen source is usually a canister or air compressor. Whether in home or hospital, plastic tubing connects the oxygen source to the patient.
Oxygen is most commonly delivered to the patient via a nasal cannula or mask attached to the tubing. The nasal cannula is usually the delivery device of choice since it is well tolerated and doesn’t interfere with the patient’s ability to communicate, eat, or drink. The concentration of oxygen inhaled depends upon the prescribed flow rate and the ventilatory minute volume (MV).
Another delivery option is transtracheal oxygen therapy, which involves a small flexible catheter inserted in the trachea or windpipe through a tracheostomy tube. In this method, the oxygen bypasses the mouth, nose, and throat, and a humidifier is required at flow rates of 1 liter (2.1 pt) per minute and above. Other oxygen delivery methods include tents and specialized infant oxygen delivery systems.
TYPES OF OXYGEN DELIVERY SYSTEMS. The types of oxygen delivery systems include:
- Compressed oxygen—oxygen that is stored as a gas in a tank. A flow meter and regulator are attached to the oxygen tank to adjust oxygen flow. Tanks vary in size from very large to smaller, portable tanks. This system is generally prescribed when oxygen is not needed constantly (e.g., when it is only needed when performing physical activity).
- Liquid oxygen—oxygen that is stored in a large stationary tank that stays in the home. A portable tank is available that can be filled from the stationary tank for trips outside the home. Oxygen is liquid at very cold temperatures. When warmed, liquid oxygen changes to a gas for delivery to the patient.
- Oxygen concentrator—electric oxygen delivery system approximately the size of a large suitcase. The concentrator extracts some of the air from the room, separates the oxygen, and delivers it to the patient via a nasal cannula. A cylinder of oxygen is provided as a backup in the event of a power failure, and a portable tank is available for trips outside the home. This system is generally prescribed for patients who require constant supplemental oxygen or who must use it when sleeping.
- Oxygen conserving device, such as a demand inspiratory flow system or pulsed-dose oxygen delivery system— uses a sensor to detect when inspiration (inhalation) begins. Oxygen is delivered only upon inspiration, thereby conserving oxygen during exhalation. These systems can be used with either compressed or liquid oxygen systems, but are not appropriate for all patients.
A physician’s order is required for oxygen therapy, except in emergency use. The need for supplemental oxygen is determined by inadequate oxygen saturation, indicated in blood gas measurements, pulse oximetry, or clinical observations. The physician will prescribe the specific amount of oxygen needed by the patient. Some patients require supplemental oxygen 24 hours a day, while others may only need treatments during exercise or sleep. No special patient preparation is required to administer oxygen therapy.
SELECTING AN OXYGEN SYSTEM. A health care provider will meet with the patient to discuss the oxygen systems available. A system recommendation will be made, based on the patient’s overall condition and personal needs, as well as the system’s ease of use, reliability, cost, range of oxygen delivery, and features. The health care provider can give the patient a list of medical supply companies that stock home oxygen equipment and supplies. The patient can meet with home care representatives from these companies to evaluate the product lines that best fit his or her needs. Patients in the home setting are directed to notify the vendors when replacement oxygen supplies are needed.
OXYGEN SAFETY. Patients will receive instructions about the safe use of oxygen in the home. Patients must be advised not to change the flow rate of oxygen unless directed to do so by the physician.
Oxygen supports combustion, therefore no open flame or combustible products should be permitted when oxygen is in use. These include petroleum jelly, oils, and aerosol sprays. A spark from a cigarette, electric razor, or other electrical device could easily ignite oxygen-saturated hair or bedclothes around the patient. Explosion-proof plugs should be used for vaporizers and humidifier attachments. The patient should be sure to have a functioning smoke detector and fire extinguisher in the home at all times.
Care must be taken with oxygen equipment used in the home or hospital. The oxygen system should be kept clean and dust-free. Cylinders should be kept in carts, or have collars for safe storage. If not stored in a cart, smaller canisters may be lain on the floor. Knocking cylinders together can cause sparks, so bumping them should be avoided. In the home, the oxygen source must be placed at least 6 ft (1.8 m) away from flames or other sources of ignition, such as a lit cigarette. Oxygen tanks should be kept in a well–ventilated area. Oxygen tanks should not be kept in the trunk of a car. “No Smoking—Oxygen in Use” signs should be used to warn visitors not to smoke near the patient.
Special care must be given when administering oxygen to premature infants because of the danger of high oxygen levels causing retinopathy of prematurity, or contributing to the construction of ductus arteriosis. PaO2 (partial pressure of oxygen) levels greater than 80 mm Hg should be avoided.
Patients who are undergoing a laser bronchoscopy should receive concurrent administration of supplemental oxygen to avoid burns to the trachea.
The patient should check with his or her insurance provider to determine if the treatment is covered and what out-of-pocket expenses may be incurred. Oxygen therapy is usually fully or partially covered by most insurance plans, including Medicare, when prescribed according to specific guidelines. Usually test results indicating the medical necessity of the supplemental oxygen are needed before insurance clearance is granted.
Traveling with oxygen requires advanced planning. The patient needs to obtain a letter from his or her health care provider that verifies all medications, including oxygen. In addition, a copy of the patient’s oxygen prescription must be shown to travel personnel. Home health care companies can help the patient make travel plans, and can arrange for oxygen when the patient arrives at his or her destination. Patients cannot bring or use their own oxygen tanks on an airplane; therefore the patient must leave his or her portable oxygen tank at the airport before boarding. Oxygen suppliers can pick up the oxygen unit from the airport if necessary, or a family member can take it home.
Once oxygen therapy is initiated, periodic assessment and documentation of oxygen saturation levels is required. Follow-up monitoring includes blood gas measurements and pulse oximetry tests. If the patient is using a mask or a cannula, gauze can be tucked under the tubing to prevent irritation of the cheeks or the skin behind the ears. Water-based lubricants can be used to relieve dryness of the lips and nostrils.
Oxygen is not addictive and causes no side effects when used as prescribed. Complications from oxygen therapy used in appropriate situations are infrequent. Respiratory depression, oxygen toxicity, and absorption atelectasis are the most serious complications of oxygen overuse.
A physician should be notified and emergency services may be required if the following symptoms develop:
- frequent headaches
- cyanotic (blue) lips or fingernails
- slow, shallow, difficult, or irregular breathing
Oxygen delivery equipment may present other problems. Perforation of the nasal septum as a result of using a nasal cannula and non-humidified oxygen has been reported. In addition, bacterial contamination of nebulizer and humidification systems can occur, possibly leading to the spread of pneumonia. High-flow systems that employ heated humidifiers and aerosol generators, especially when used by patients with artificial airways, also pose a risk of infection.
A normal result is a patient that demonstrates adequate oxygenation through pulse oximetry, blood gas tests, and clinical observation. Signs and symptoms of inadequate oxygenation include cyanosis, drowsiness, confusion, restlessness, anxiety, or slow, shallow, difficult, or irregular breathing. Patients with obstructive airway disease may exhibit “aerophagia” (air hunger) as they work to pull air into the lungs. In cases of carbon monoxide inhalation, the oxygen saturation can be falsely elevated.
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Hyatt, Robert E., Paul D. Scanlon, Masao Nakamura,. Interpretation of Pulmonary Function Tests: A Practical Guide, 2nd ed. Philadelphia: Lippincott Williams and Wilkins Publishers, 2003.
Wilkins, Robert, et al. Egan’s Fundamentals of Respiratory Care, 8th ed. St. Louis: Mosby, 2003.
Yutsis, Pavel I. Oxygen to the Rescue: Oxygen Therapies and How They Help Overcome Disease, Promote Repair, and Improve Overall Function. Basic Health Publications, Inc., 2003.
American Association for Cardiovascular and Pulmonary Rehabilitation (AACVPR). 7600 Terrace Avenue, Suite 203, Middleton, Wisconsin 53562. (608) 831-6989. E-mail: [email protected] http://www.aacvpr.org.
American College of Chest Physicians. 3300 Dundee Road, Northbrook, Illinois 60062-2348. (847) 498-1400. http://www.chestnet.org.
National Heart, Lung and Blood Institute. Information Center. P.O. Box 30105, Bethesda, Maryland 20824. (301) 251-2222. http://www.nhlbi.nih.gov/nhlbi/.
National Jewish Medical and Research Center. Lung-Line. 14090 Jackson Street, Denver, Colorado 80206. http://www.nationaljewish.org.
Daily Lung. http://www.dailylung.com. A full-feature magazine covering lung disease and related health topics.
National Lung Health Education Program. http://www.nlhep.org.
Pulmonary Paper. P.O. Box 877, Ormond Beach, Florida 32175. (800) 950-3698. http://www.pulmonarypaper.-¥org. Not-for-profit newsletter supporting people with chronic lung problems.
Maggie Boleyn, R.N., B.S.N.
Angela M. Costello
Rosalyn Carson-DeWitt, MD
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