In the 17th century bridge construction demanded workers dive to great underwater depths with the introduction of caissons (a chamber, usually of steel but sometimes of wood or reinforced concrete, used in the construction of foundations or piers in or near a body of water). The air in the chamber is kept under pressure great enough to prevent the entrance of water, while shafts through the bulkhead permit the passage of workers, equipment, and excavated material between the bottom and the surface. Workers frequently suffered from caisson’s disease (the “bends”) and were treated in metallic vessels large enough to hold people and strong enough to hold air under pressure. These vessels, combined with newly-developed air compressors, resulted in the enabled treatment of patients with hyperbaric air decompression. This represented the first reports of decompression sickness; the caisson workers assumed a bent posture (the “bends”) to help relieve the pain caused by nucleation of accrued nitrogen in their joints as they emerged from depths of up to 70 feet.

Conventional western medicine uses HBOT to treat the following:

Uncontrolled Decompression during Diving: results in one of two types of decompression sickness (DCS).

*DCS I involves only the extremities (arms/legs) and the joints
*DCS II involves the central nervous system (brain/spinal cord)

Treatment involves recompressing the patient in 100% oxygen, followed by controlled decompression using data developed by the U.S. Navy.

Carbon Monoxide Poisoning: This colorless, odorless gas passes readily through alveoli (lung tissue air sacs) into the blood where it binds tightly to oxygen-carrying proteins in the blood (hemoglobin). Carbon monoxide also locks up the energy factory machinery (cytochrome system) inside each cell’s mitochondria. This prevents our bodies from being able to use oxygen. The use of HBOT to treat carbon monoxide poisoning is controversial. It is used to prevent/treat the development of neurologic injury in patients with severe exposure to this deadly gas. Usually, patients undergo one or two 90-minute treatments at 2-3 atmospheres (2-3 times the atmospheric pressure at sea level).

Difficult Wounds: Chronic, non-healing wounds are found in a variety of clinical patients. Recent data has supported the use of HBOT in the treatment of non-healing wounds caused by irradiation. There is less data to support the use of HBOT in other clinical settings. However, HBOT is often recommended in patients with difficult clinical problems. For example, diabetes mellitus and vascular disease are notorious for late complications of non-healing wounds. Amputation of an infected lower leg is the end result in many unfortunate cases. These patients have been shown, recently, to benefit from HBOT. One study showed decreased major amputation rate in diabetic patients who underwent HBOT (30 daily 90-minute treatments at 2-3 atmospheres).

Soft Tissue Infections: with anaerobic bacteria had a lower mortality rate in patients who underwent hyperbaric oxygen therapy, according to one study. Another study showed HBOT to have no benefit in these infections. According to one author (Sheridan), HBOT seems a reasonable adjunct to surgery, if it can be safely administered without delaying standard treatment (surgery and antibiotics). Treatment would consist of 90-minute treatments at 2-3 atmospheres once or twice daily.

Alternative Medicine

Stroke: Although HBOT is used conventionally in the United States, its use is reportedly higher in other countries. Stroke patients in Germany may undergo this form of treatment according to David Hughes, D.Sc. of the Hyperbaric Oxygen Institute. Hughes states that HBOT has decreased the aftercare costs for stroke patients in Germany by as much as 71%. As recent as 1995, one French study (Nighoghossian) showed that HBOT may be helpful in the treatment of ischemic stroke. But more recent investigations (Rusyniak et al) have shown that HBOT “does not appear to be beneficial and may be harmful in patients with acute ischemic stroke”.

Peripheral Vascular Disease and Chronic Wounds: Hughes also claims that HBOT is used in France for peripheral vascular disease (PVD); which can be caused by atherosclerosis, arteriosclerosis, and diabetes, and others. PVD oftentimes results in poor wound-healing and chronic ulcers (most often on/around the foot and ankle). HBOT is not part of routine, conventional wound care for diabetic foot ulcers. It may, however, be considered for some patients. The American Diabetes Association recognizes HBOT as a potential adjunctive therapy for complex limb-threatening diabetic foot wounds unsuitable for revascularization procedures.

Multiple Sclerosis: Dr. Hughes also states that HBOT is used in Great Britain to treat Multiple Sclerosis (MS). Based on an unpublished article from 1993 by D. Perrin, Hughes cites that more than 25,000 MS patients have benefited from HBOT. But, according to Kleijnen, patients who have chronic progressive or chronic stable multiple sclerosis showed no consistent positive effects to HBOT (results based on Expanded Disability Status Score [EDSS] and the Functional Status Score). An earlier study by Kindwall (1991) treated patients in accordance with protocols that reported to produce a benefit in multiple sclerosis. Investigators were unable to substantiate any useful long-term effect of hyperbaric oxygen therapy.

The French surgeon Fontaine built a mobile compressorized operating suite in 1879. Patients reportedly had better outcomes because of improved oxygenation and decreased postoperative vomiting and cyanosis. Easier reduction of hernias was noted. Corning introduced the therapeutic compression chamber to the US in 1891 to treat nervous and mental afflictions. This chamber was the first operated by electric power.

Orville Cunningham noted 25 years later that patients with certain cardiovascular disorders improved when moved from high altitudes to sea-level altitudes. He discovered this during the Spanish flu epidemic in 1918, which resulted in more than 500,000 deaths. Many of these victims died in a cyanotic state. Under the care of Dr Cunningham, a rather sick resident physician was treated in the compression chamber and recovered completely. Cunningham subsequently built an 88-ft long and 10-ft wide chamber to treat numerous patients, with remarkable success. The credibility of the compression chamber was reinforced during treatment of flu patients. One night when the chamber’s power accidentally was shut off, all patients died. At the time, the interpretation credited hyperbaric therapy with keeping the patients alive. When the compression stopped, these patients died. However, the deaths were likely the result of rapid ascent from the compression rather than the secondary effects of the Spanish flu.

In 1928, Mr Timkin, an appreciative patient whose uremic state was resolved after receiving hyperbaric therapies, constructed for Cunningham an enormous 60-ft tall, 6-story hyperbaric hospital that looked like a steel sphere. Conditions such as hypertension, diabetes, syphilis, and cancer were treated here until 1930, when the local medical society closed the hyperbaric hospital for lack of scientific evidence or merit. After 1930, much of the medical or scientific community did not look favorably upon the use of hyperbaric medicine.

Supplemental use of oxygen increased with availability after this time. The military soon had an increased interest in underwater activities, and this promoted the use of oxygen and hyperbaric medicine for diving and decompression sickness. Hyperbaric medicine treatments had sound physiologic principles based on known physics of mixed gas when treating decompression sickness.

A flurry of interest in therapeutic hyperbaric medicine was fostered by Dr I. Boerema, who, while in Amsterdam in 1956, reported hyperbaric oxygen (HBO) as an aid in cardiopulmonary surgery, particularly for congenital conditions such as tetralogy of Fallot, transposition of great vessels, and pulmonic stenosis. A colleague of Boerema’s, W. H. Brummelkamp, also interested in hyperbaric medicine, discovered in 1959 (and subsequently published in 1961) that anaerobic infections were inhibited by hyperbaric therapy. Meanwhile, Boerema had published an article, “Life without blood,” a report of fatally anemic pigs treated successfully with volume expansion and pressurized hyperoxygenation. Boerema often is credited as the father of modern-day hyperbaric medicine.

In 1962, Smith and Sharp reported the enormous benefits of HBO in carbon monoxide poisoning. International interest thus was rekindled, and HBO therapy was thrust into the modern era. Hyperbaric units subsequently were built at Duke University, New York Mount Sinai Hospital, Presbyterian Hospital and Edgeworth Hospital in Chicago, Good Samaritan in Los Angeles, St. Barnaby Hospital in New Jersey, Harvard Children’s Hospital, and St. Luke’s Hospital in Milwaukee. Further chambers were installed in numerous international sites.

The benefits of hyperbaric medicine subsequently were observed for split-thickness skin graft acceptance, flap survival and salvage, wound re-epithelization, and acute thermal burns. These studies lent credibility to the therapeutic employment of HBO therapy. This fostered the establishment of organized scientific congresses and societies such as the International Congress on Hyperbaric Oxygen and the Undersea Medical Society. Unfortunately, as the availability of hyperbaric medicine chambers increased, the indiscriminate and inappropriate use of the chamber for a variety of medical conditions by practitioners searching for a “cure-all” therapy resulted in a backlash from the scientific society, once again tarnishing the credibility of hyperbaric medicine. As a result, by the late 1970s, the Undersea Medical Society had formulated guidelines for the use of hyperbaric therapy.

Researchers conducting wound-healing studies continued to try to take advantage of the angiogenic properties of increasing oxygen gradients resulting from hyperbaric therapy. Foot wounds from diabetes, radiation ulcers, and other ischemic wounds have been manipulated and successfully treated with HBO. Prospective blinded randomized trials and well-executed laboratory studies continue to further define the role of hyperbaric therapy in medical therapeutics.

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.

Purpose

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 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 or pneumonia)
* 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 post-anesthesia 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.

Description
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.

Preparation

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.

Patient education

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.

Insurance clearance

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.

Travel guidelines

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.

Aftercare

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.

Risks

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
* anxiety
* cyanotic (blue) lips or fingernails
* drowsiness
* confusion
* restlessness
* 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.
Normal results

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.

More and more people are using oxygen therapy outside the hospital, permitting them to lead active, productive lives. People with asthma, emphysema, chronic bronchitis, occupational lung disease, lung cancer, cystic fibrosis, or congestive heart failure may use oxygen therapy at home.

The Prescription
A physician must write a prescription for oxygen therapy. The prescription will spell out the flow rate, how much oxygen you need per minute — referred to as liters per minute (LPM or L/M) — and when you need to use oxygen. Some people use oxygen therapy only while exercising, others only while sleeping, and still others need oxygen continuously. Your physician will order a blood test that will indicate what your oxygen level is and help determine what your needs are.

The Equipment
There are three common ways of providing oxygen therapy. Oxygen can be delivered to your home in the form of a gas in various-sized cylinders or as a liquid in a vessel. The third way to provide oxygen therapy is by using an oxygen concentrator. Each method is examined in more detail below.

Compressed Gas – Oxygen is stored under pressure in a cylinder equipped with a regulator that controls the flow rate. Because the flow of oxygen out of the cylinder is constant, an oxygen-conserving device may be attached to the system to avoid waste. This device releases the gas only when you inhale and cuts it off when you exhale. Oxygen can be provided in a small cylinder that can be carried with you, but the large tanks are heavy and are only suitable for stationary use.

Liquid Oxygen – Oxygen is stored as a very cold liquid in a vessel very similar to a thermos. When released, the liquid converts to a gas and you breathe it in just like the compressed gas. This storage method takes up less space than the compressed gas cylinder, and you can transfer the liquid to a small, portable vessel at home. Liquid oxygen is more expensive than the compressed gas, and the vessel vents when not in use. An oxygen conserving device may be built into the vessel to conserve the oxygen.

Oxygen Concentrator – This is an electrically powered device that separates the oxygen out of the air, concentrates it, and stores it. This system has a number of advantages because it doesn’t have to be resupplied and it is not as costly as liquid oxygen. Extra tubing permits the user to move around with minimal difficulty. Small, portable systems have been developed that afford even greater mobility. You must have a cylinder of oxygen as a backup in the event of a power failure. You should advise your electric power company in order to get priority service when there is a power failure.

Oxygen Delivery Devices
There are three common means of oxygen delivery. A nasal cannula is a two-pronged device inserted in the nostrils that is connected to tubing carrying the oxygen. The tubing can rest on the ears or be attached to the frame of eyeglasses.

People who need a high flow of oxygen generally use a mask. Some people who use a nasal cannula during the day prefer a mask at night or when their noses are irritated or clogged by a cold.

Transtracheal oxygen therapy requires the insertion of a small flexible catheter in the trachea or windpipe. The transtracheal catheter is held in place by a necklace. Since transtracheal oxygen bypasses the mouth, nose, and throat, a humdifier is absolutely required at flow rates of 1 LPM or greater.

Safety
You should never smoke while using oxygen. Warn visitors not to smoke near you when you are using oxygen. Put up no-smoking signs in your home where you most often use the oxygen. When you go to a restaurant with your portable oxygen source, ask to be seated in the nonsmoking section. Stay at least five feet away from gas stoves, candles, lighted fireplaces, or other heat sources. Don’t use any flammable products like cleaning fluid, paint thinner, or aerosol sprays while using your oxygen.

If you use an oxygen cylinder, make sure it is secured to some fixed object or in a stand. If you use liquid oxygen, make sure the vessel is kept upright to keep the oxygen from pouring out; the liquid oxygen is so cold it can hurt your skin. Keep a fire extinguisher close by, and let your fire department know that you have oxygen in your home. If you use an oxygen concentrator, notify your electric company so you will be given priority if there is a power failure. Also, avoid using extension cords if possible.

Care of Equipment
The home medical equipment and services company that provides the oxygen therapy equipment you use should provide you with instructions on user care and maintenance of your particular equipment. Here are some general guidelines for your cleaning procedures. You should wash your nasal prongs with a liquid soap and thoroughly rinse them once or twice a week. Replace them every two to four weeks. If you have a cold, change them when your cold symptoms have passed.

Check with your health care provider to learn how to clean your transtracheal catheter. The humidifier bottle should be washed with soap and warm water and rinsed thoroughly between each refill. Air dry the bottle before filling with sterile or distilled water. The bottle and its top should be disinfected after they are cleaned.

If you use an oxygen concentrator, unplug the unit, then wipe down the cabinet with a damp cloth and dry it daily. The air filter should be cleaned at least twice a week. Follow your home medical equipment and services company’s directions for cleaning the compressor filter.

Do’s and Don’ts

* Don’t ever change the flow of oxygen unless directed by your physician.
* Don’t use alcohol or take any other sedating drugs because they will slow your breathing rate.
* Make sure you order more oxygen from your dealer in a timely manner.
* Use water-based lubricants on your lips or nostrils. Don’t use an oil-based product like petroleum jelly.
* To prevent your cheeks or the skin behind your ears from becoming irritated, tuck some gauze under the tubing. If you have persistent redness under your nose, call your physician.

Trouble
Call your physician if you experience frequent headaches, anxiety, blue lips or fingernails, drowsiness, confusion, restlessness, anxiety, or slow, shallow, difficult, or irregular breathing. Also, call your physician if you feel any symptoms of illness.

Medicare, Medicaid, and Commercial Insurance
Certain insurance policies may pay for all your oxygen, but payment is based on laboratory results, diagnosis, and other information. Your physician or medical equipment and services provider may be able to answer your questions about coverage.