Passengers on U.S. commercial aircraft now may bring any of 11 different portable oxygen concentrators on board and use them, with the approval of the aircraft operator, thanks to an FAA final rule that was published and immediately effective Wednesday.

The rule signed by FAA Administrator Randy Babbitt amended Special Federal Aviation Regulation 106, Use of Certain Portable Oxygen Concentrator Devices on Board Aircraft, to allow the use of DeVilbiss Healthcare Inc.’s iGo, International Biophysics Corporation’s LifeChoice, Inogen Inc.’s Inogen One G2, and Oxlife LLC.’s Oxlife Independence Oxygen Concentrator.

POCs are small, FDA-regulated machines that separate oxygen from nitrogen and other gases contained in ambient air and dispense it in concentrated form to the user, with an oxygen concentration of about 90 percent. They can use rechargeable batteries or, if the aircraft operator obtains FAA approval, aircraft electrical power, and the Pipeline and Hazardous Materials Safety Administration has determined the four POCs are not hazardous materials. That means they do not require the same level of special handling as compressed oxygen and are safe for use on board aircraft, provided certain conditions for their use are met.

SFAR 106, originally published in July 2005, already allowed passengers to carry on and use AirSep Corporation’s LifeStyle and FreeStyle; Inogen’s Inogen One; SeQual Technologies’ Eclipse; Philips Respironics Inc.’s EverGo; Delphi Medical Systems’ RS-00400; and Invacare Corporation’s XPO2.

The contact for more information about this rule is David Catey of the Air Transportation Division, FAA Flight Standards Service, at 202-267-8166.

In the rule, FAA said it still intends to develop a performance-based standard for all future POC devices but wants to ensure such a standard does not hamper innovative technologies by the manufacturers. “This process is time-consuming and we intend to publish a notice in the Federal Register and offer the public a chance to comment on the proposal when it is complete. In the meantime, manufacturers continue to create new and better POCs, and several have requested that their product also be included as an acceptable device in SFAR 106,” the agency explained.

Hidden from sight, our cells battle challenges such as their environment, bacteria, viruses, too much or too little oxygen, and physiological stressors. Molecular systems protect cells under assault, but those systems can break down, especially with age.

To better understand how cells are protected from stress and damage, a team led by Northwestern University researchers studied the effect of resveratrol, a beneficial chemical found in red wine, on human cells in tissue culture.

The findings may help explain what happens in neurodegenerative diseases, which are age-related, when cell protection fails, proteins misfold, lots of damage accumulates and the system falls apart.

The researchers discovered a new molecular relationship critical to keeping cells healthy across a long span of time: a protein called SIRT1, important for caloric restriction and lifespan and activated by resveratrol, regulates heat shock factor 1 (HSF1), keeping it active. HSF1 in turn senses the presence of damaged proteins in the cell and elevates the expression of molecular chaperones to keep a cell’s proteins in a folded, functional state. Regulation of this pathway has a direct beneficial effect to cells, the research shows.

This role of SIRT1 — a protein already of great interest to pharmaceutical companies — was not previously known. The results will be published in the Feb. 20 issue of the journal Science.

“When SIRT1 levels are high, you are in a high-protection mode,” said Richard I. Morimoto, Bill and Gayle Cook Professor of Biochemistry, Molecular Biology and Cell Biology in Northwestern’s Weinberg College of Arts and Sciences. He led the research team.

“Ironically, triggering the stress response and perhaps maintaining the cell in a protective state over a long period of time can keep cells healthy,” said Morimoto. “The cell is protected against an accumulation of damage when HSF1 is more active.”

SIRT1 levels decrease as humans age, Morimoto explains. Cells can’t respond to stress as well. This decrease in SIRT1 may help explain why protein misfolding diseases, such as Alzheimer’s, Parkinson’s, Huntington’s and adult-onset diabetes, are diseases of aging.

“We now have a powerful way to think about addressing neurodegenerative diseases,” said Morimoto. “We have identified a pathway that can be manipulated to alter lifespan. Discovering this new basis for therapeutics is very exciting.”

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.

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.

Several therapeutic principles are made use of in HBOT:

* The increased overall pressure is of therapeutic value when HBOT is used in the treatment of decompression sickness and air embolism.
* For many other conditions, the therapeutic principle of HBOT lies in a drastically increased partial pressure of oxygen in the tissues of the body. The oxygen partial pressures achievable under HBOT are much higher than those under breathing pure oxygen at normobaric conditions (i.e. at normal atmospheric pressure).
* A related effect is the increased oxygen transport capacity of the blood. Under atmospheric pressure, oxygen transport is limited by the oxygen binding capacity of hemoglobin in red blood cells and very little oxygen is transported by blood plasma. Because the hemoglobin of the red blood cells is almost saturated with oxygen under atmospheric pressure, this route of transport cannot be exploited any further. Oxygen transport by plasma, however is significantly increased under HBOT.

Uses

The United States, the Undersea and Hyperbaric Medical Society, known as UHMS, approved for reimbursement diagnoses for application of HBOT in hospitals. The following indications are approved uses of hyperbaric oxygen therapy as defined by the UHMS Hyperbaric Oxygen Therapy Committee.

* Air or gas embolism
* Carbon monoxide poisoning
o Carbon Monoxide Poisoning Complicated by Cyanide Poisoning
* Clostridal Myositis and Myonecrosis (Gas gangrene)
* Crush Injury, Compartment syndrome, and other Acute Traumatic Ischemias
* Decompression sickness
* Enhancement of Healing in Selected Problem Wounds
* Exceptional Blood Loss (Anemia)
* Intracranial Abscess
* Necrotizing Soft Tissue Infections (Necrotizing fasciitis)
* Osteomyelitis (Refractory)
* Delayed Radiation Injury (Soft Tissue and Bony Necrosis)
* Skin Grafts & Flaps (Compromised)
* Thermal Burns

In the United States, HBOT is recognized by Medicare as a reimbursable treatment for 14 UHMS “approved” conditions. An HBOT session costs anywhere from $100 to $200 in private clinics, to over $1,000 in hospitals. U.S. physicians may lawfully prescribing HBOT for “off-label” conditions such as Lyme Disease, stroke and migraines. Such patients are treated in outpatient clinics. In the United Kingdom most chambers are financed by the National Health Service, although some, such as those run by Multiple Sclerosis Therapy Centres, are non-profit.

Other reported applications include:

* Diabeticaly derived illness, such as diabetic foot, diabetic retinopathy, diabetic nephropathy
* Epidural abscesses
* Certain kind of hearing loss
* Radiation-induced hemorrhagic cystitis
* Inflammatory bowel disease

HBOT is controversial and health policy regarding its uses is politically charged. Both sides of the controversy on the effectiveness of HBOT is available in the form of Cochrane Library reviews.

Structure

Traditional

The traditional type of hyperbaric chamber used for HBOT is a hard shelled pressure vessel. Such chambers can be run at absolute pressures up to 600 kilopascals or 85 PSI (lbf/in²), nearly six atmospheres.

Navies, diving organizations and hospitals typically operate these. They range in size from those which are portable and capable of treating just one patient to those which are fixed, very heavy and capable of treating eight or more patients.

The chamber may consist of:

* a pressure vessel that is generally made of steel and aluminium with the view ports (windows) or hull made of acrylic.
* one or more human entry hatches—these could be small and circular or wheel-in type hatches for patients on trolleys
* an airlock allowing human entry—a separate chamber with two hatches, one to the outside world and one to the main chamber, which can be independently pressurized to allow patients to enter or exit the main chamber while it is still pressurized
* an airlock allowing medicines, instruments and food to enter the main chamber
* glass ports or closed-circuit television allowing the technicians and medical staff outside the chamber to monitor the inside of the chamber
* an intercom allowing two-way communications inside and outside the chamber
* a carbon dioxide scrubber—consisting of a fan that passes the gas inside the chamber through a soda lime canister
* a control panel outside the chamber is used to open and close valves allowing air to enter or leave the chamber and oxygen to be supplied to oxygen helmets or masks

Oxygen breathing

Breathing 100% oxygen from an aviators’ oxygen mask.
A recompression chamber for a single diving casualty

In today’s larger “multiplace” chambers, both patients and medical staff inside the chamber breathe from “oxygen helmets”, flexible, transparent soft plastic helmets with a seal around the neck similar to a space suit helmet, or tightly fitting aviators oxygen masks, which supply pure oxygen and remove the exhaled gas from the chamber. During treatment patients breathe 100% oxygen most of the time but have periodic air breaks to minimize the risk of oxygen toxicity. The exhaled gas must be removed from the chamber to prevent the build up of oxygen, which could provoke a fire. Medical staff may also breathe oxygen to reduce the risk of decompression sickness. Administration of 100% breathing oxygen maximizes the patient’s treatment. The pressure inside the chamber is increased by opening valves allowing high-pressure air to enter from storage cylinders, similar to diving cylinders. A gas compressor is used to fill these cylinders.

Smaller “monoplace” chambers can only accommodate the patient. No medical staff can enter. The chamber is flooded with pure oxygen or compressed air. The cost of using pure oxygen in a monoplace chamber is much higher than using compressed air. If pure oxygen is used no oxygen breathing mask or helmet is needed. If compressed air is used then an oxygen mask or helmet is needed as in a multiplace chamber. In monoplace chambers that are compressed with pure oxygen a mask is available to provide the patient with “air breaks,” periods of breathing normal air, in order to reduce the risk of hyperoxic seizures.

Effects of Pressure

Patients inside the chamber will notice discomfort inside their ears as a pressure difference develops between their middle ear and the chamber atmosphere. This can be relieved by the Valsalva maneuver or by “jaw wiggling”. As the pressure increases further, mist may form in the air inside the chamber and the air may become warm. When the patient speaks, the pitch of the voice may increase to the level that they sound like cartoon characters.

To reduce the pressure, a valve is opened to allow gas out of the chamber. As the pressure falls, the patient’s ears may “squeak” as the pressure inside the ear equalizes with the chamber. The temperature in the chamber will fall.

Home treatment

There are portable HBOT chambers, which are used for home treatment. These are usually referred to as “mild chambers”, which is a reference to the lower pressure of soft-sided chambers. Those commercially available in the USA go up to 4 PSI (1.27 ATA 8.92 FSW). International portable chambers can go to 7.35 psi (1.5 ATA 16.38 FSW) or higher. These chambers are operated with oxygen concentrators (typically 95% oxygen) or with 100% oxygen as the breathing gas. Total concentration of oxygen should not exceed 25% as this can increase the risk of fire.

These chambers are often used in a clinical settings, but are also used in homes. Mild hyperbaric chambers use standard 120 volt outlets and can also be configured for 220 volt use. Ranging in size from 21″ up to 40″ in diameter these chambers measure between 84″ to 120″ in length. The soft chambers are FDA approved only for the treatment of altitude sickness but are commonly used off label primarily for the treatment of autism and other neural conditions though there is no proof that it is effective and hospitals refuse to allow their chambers to be used for this purpose. The FDA has a specific warning that supplemental oxygen is not to be used.

Treatments

Initially, HBOT was developed as a treatment for diving disorders involving bubbles of gas in the tissues, such as decompression sickness and gas embolism. The chamber cures decompression sickness and gas embolism by increasing pressure, reducing the size of the gas bubbles and improving the transport of blood to downstream tissues. The high concentrations of oxygen in the tissues are beneficial in keeping oxygen-starved tissues alive, and have the effect of removing the nitrogen from the bubble, making it smaller until it consists only of oxygen which is then re-absorbed into the body. After elimination of bubbles, the pressure is gradually reduced back to atmospheric levels.

Protocol

The slang term for a cycle of pressurization inside the HBOT chamber is “a dive”. An HBOT treatment for longer-term conditions is often a series of 20 to 40 dives.

Emergency HBOT for diving disorders typically follows one of two forms. For most cases, a shallow “dive” to a pressure the equivalent of 18 meters / 60 feet of water for 3 to 4.5 hours with the casualty breathing pure oxygen with air breaks every 20 minutes to reduce oxygen toxicity. For extremely serious cases, a deeper “dive” to a pressure the equivalent of 37 meters / 122 feet of water for 4.5 hours with the casualty breathing air.

In Canada and the United States, the U.S. Navy Dive Charts are used to determine the duration, pressure and breathing gas of the therapy. The most frequently used tables are Table 5 and Table 6. In the UK the Royal Navy 62 and 67 tables are used.

The Undersea and Hyperbaric Medical Society[57] (UHMS) publishes a report which compiles the latest research findings and contains information regarding the recommended duration and pressure of the longer-term conditions.

Possible complications

There are risks associated with HBOT, similar to some diving disorders. Pressure changes can cause a “squeeze” or barotrauma in the tissues surrounding trapped air inside the body, such as the lungs[58], behind the eardrum[59][60], inside paranasal sinuses[59], or trapped underneath dental fillings[61]. Breathing high-pressure oxygen for long periods can cause oxygen toxicity. Temporarily blurred vision can be caused by swelling of the lens, which usually resolves in two to four weeks.[62][63]

There are reports that cataract may progress following HBOT.[64] Also a rare side effect has been blindness secondary to optic neuritis (inflammation of the optic nerve).[citation needed]

Contraindications

The only absolute contraindication to hyperbaric oxygen therapy is untreated pneumothorax.[65] Also, the treatment may raise the issue of Occupational safety and health (OHS), which has been encountered by the therapist.[66][clarification needed]

Patients should not undergo HBO therapy if they are taking or have recently taken the following drugs:

* Doxorubicin (Adriamycin) – A chemotherapeutic drug.
* Disulfiram (Antabuse) – Used in the treatment of alcoholism.
* Cis-platinum – A cancer drug.
* Mafenide acetate (Sulfamylon) – Suppresses bacterial infections in burn wounds

The following are relative contraindications:

* Upper respiratory infections – These conditions can make it difficult for the patient to clear their ears, which can result in what is termed sinus squeeze.
* High fevers – In most cases the fever should be lowered before HBO treatment begins.
* Emphysema with CO2 retention – This condition can lead to pneumothorax during HBO treatment.
* History of thoracic (chest) surgery – This is rarely a problem and usually not considered a contraindication. However, there is concern that air may be trapped in lesions that were created by surgical scarring. These conditions need to be evaluated prior to considering HBO therapy.
* Malignant disease: Since cancers both thrive in blood rich environments and may be suppressed in high oxygen environments, cancer and HBO poses a dilemma since HBO both increases blood flow via angiogenesis and also raises oxygen levels. Taking an anti-angiogenic supplement may provide a solution to this problem.
* Middle ear barotrauma (MEBT) is always a consideration in treating both children and adults in a hyperbaric environment, but most children currently being treated with HBOT are being pressurized to 1.3 ATA which reduces the risks of potential side effects.

Neuro-rehabilitation
The Collet (Quebec) trial that was published in the Lancet in 2001 was the largest randomized trial of Hyperbaric Oxygen Therapy (HBOT) for children with cerebral palsy (CP); it followed the McGill pilot study on the same subject.

The evidence showed both groups of children treated with two very different hyperbaric treatment dosages improved significantly. The motor improvements that were seen and measured with the gross motor function measure were greater, more generalized, and were obtained in a shorter period of time than most of the changes found in any other studies of recognized conventional therapies in the treatment of children with cerebral palsy. The children in both groups improved an average of ten times more during the two months of HBOT (whilst all other therapies and medication were stopped) than during the three months follow-up (when medication and all the ancillary treatments were restarted). This impressive change in the rate of improvements clearly indicates the probable effectiveness of hyperbaric treatment. Both the Lancet commentary and the tech report by the Agency for Healthcare Research and Quality (AHRQ) concluded that the hypothesis of both treatments being equally effective should be retained.

Since the Quebec study of HBOT for children with CP, many reports have been made on the possible efficacy of a low pressure hyperbaric treatment and all the trials conducted with HBOT in CP have demonstrated positive results.

An editorial on CP published by the Undersea and Hyperbaric Medical Society in 2007 called for further research that will include “basic science research to determine a reasonable mechanism of action” for hyperbaric oxygenation as well as “clinical studies of the highest possible methodological rigor”.

Some medical practitioners recommend the use of HBOT for the treatment of acute tinnitus but this treatment has not been verified by independent evidence and the treatment was withdrawn from support by the German health insurance. There is evidence that the therapeutic effects could be greatly due to psychological mechanisms triggered by the patients attitude towards therapy prior to the treatment.

The earliest randomized, placebo-controlled, double-blind study on multiple sclerosis patients treated with HBOT suggested the therapy could improve balance and bladder function. However, by 2004 a Cochrane review assessing ten trials and 21 analyses “found no consistent evidence to confirm a beneficial effect of hyperbaric oxygen therapy for the treatment of multiple sclerosis and do not believe routine use is justified.

For more informaton on Hyperbaric Chambers

Oxygen first aid specifically refers to the use of oxygen in a first aid setting. Oxygen will assist patients with myocardial infarction and hypoxia (low blood oxygen levels). Care needs to be exercised in patients with chronic obstructive pulmonary disease, especially in those known to retain carbon dioxide (type II respiratory failure) who lose their respiratory drive and accumulate carbon dioxide if administered oxygen in moderate concentration. However the risk of the loss of respiratory drive are far outweighed by the risks of withholding emergency oxygen, and therefore emergency administration of oxygen is never contraindicated.

Home or domiciliary oxygen therapy

This refers to the administration of oxygen as ongoing therapy, either continuously or intermittently. Most commonly patients on home oxygen therapy have severe chronic obstructive pulmonary disease caused by smoking. High concentration (approaching 100%) oxygen is used as home therapy to abort cluster headache attacks, due to its vaso-constrictive effects.[1] It is indicated in COPD patients with PaO2 ≤ 55mmHg or SaO2 ≤ 88% and has been shown in a Medical Research Council study to increase survival.

Oxygen sources and delivery
Gas canisters containing oxygen to be used at home. When in use a pipe is attached to the top of the can and then to a mask that fits over the patient’s nose and mouth.
A home oxygen concentrator in situ in an Emphysema patient’s house. The model shown is the DeVILBISS LT 4000.

There are three typical sources of oxygen used therapeutically:

1. Liquid oxygen is contained in thermally insulating tanks. The liquid has to boil changing into a gas for breathing. Large tanks are used by hospitals. Small tanks can be used domestically. Liquid oxygen tanks are refilled by liquid oxygen suppliers.

2. Cylinders contain compressed gaseous oxygen. Small cylinders are used for first aid and for home oxygen patients when mobility is required. Cylinders are refilled by a gas supplier.

3. Oxygen concentrators are electrically powered devices which remove nitrogen from air. They are most commonly used in a domestic situation, because they do not need refilling. However, a number of manufacturers have introduced portable oxygen concentrators. These have replaced[2] the need to use liquid or gas cylinders for mobility for many patients. Portable Oxygen Concentrators allow patients to freely travel without the need of gas or liquid. The FAA has approved portable oxygen concentrators for the use on many commercial airlines. Most major airlines allow the three major portable oxygen concentrators; it is necessary to check in advance if a particular brand or model is permitted on a particular airline. These can typically use AC, DC, or battery power. Some portable concentrators have only pulse or demand flow capabilities, while continuous flow portables are available. Pulse or demand flow is similar to the way an oxygen conserving device delivers oxygen from liquid oxygen or a gas cylinder only during inhalation, but on a concentrator, the oxygen made in between pulses is stored for the next pulse. Where a conserving device can make a liquid or gas container last longer, pulse or demand settings on oxygen concentrators can make a certain flow appear as a higher effective flow, or reduce power consumption and/or extend battery life.

First aid kits have been produced that create oxygen gas as the result of a chemical reaction between lightweight or widely available substances such as sodium percarbonate and water, although the rate and duration of oxygen supply is not high.

Oxygen is most often delivered as continuous gaseous flow, measured in litres per minute (lpm).

Low-Flow Devices

Low-flow systems deliver oxygen at flows that are less than the patient’s inspiratory flowrate (ie, the delivered oxygen is diluted with room air) and, thus, the oxygen concentration inhaled may be low or high, depending on the specific device and the patient’s inspiratory flowrate.

1. The nasal cannula (NC) is a thin tube with two small nozzles that protrude into the patients nostrils. It can only comfortably provide oxygen at low flow rates, 0.25-6 litres per minute (LPM), delivering a concentration of 24-40%. Flow rates greater than 4 liters per minute can cause discomfort and dry out the nasal passages and should also be used with a humidifcation system.

2. The simple face mask (SFM) is a basic mask used for non-life-threatening conditions but which may progress in time, such as chest pain (possible heart attacks), dizziness, and minor hemorrhages. It is often set to deliver oxygen between 5-15 LPM. The final oxygen concentration delivered by this device is dependent upon the amount of room air that mixes with the oxygen the patient breathes. The general oxygen concentration is between 35% and 50%

1. The Partial rebreathing mask is a simple mask with a reservoir bag. Oxygen flow should always be supplied to maintain the reservior bag at least one third to one half full on inspiration, usually 5-15 LPM. At a flow of 6-10 L/min the system can provide 40-70% oxygen.

High-Flow Devices

High-flow systems deliver a prescribed gas mixture — either high or low FDO2 at flowrates that exceed patient demand.

1. The non-rebreather mask (NRB) is similar to the partial rebreathing mask except it has a series of one-way valves. One valve is placed between the bag and the mask to prevent exhaled air from returning to the bag. There should be a minimum flow of 10 L/min. The delivered FIO2 of this system is 60-80%, depending on the oxygen flow and breathing pattern.

1. Air-entrainment masks, also known as Venturi masks, can accurately deliver predetermined oxygen concentration to the trachea up to 40%. Jet-mixing masks rated at 35% or higher usually however do not deliver flowrates adequate to meet the inspiratory flowrates of adults in respiratory distress. Aerosol masks, tracheostomy collars, T-tube adapters, and face tents can be used with high-flow supplemental oxygen systems. A continuous aerosol generator or large-volume reservoir humidifier can humidify the gas flow. Some aerosol generators however, cannot provide adequate flows at high oxygen concentrations.

Filtered Oxygen Masks

Filtered oxygen masks have the ability to prevent exhaled, potentially infectious particles from being released into the surrounding environment. These masks are normally of a closed design such that leaks are minimized and breathing of room air is controlled through a series of one-way valves. Filtration of exhaled breaths is accomplished either by placing a filter on the exhalation port, or through an integral filter that is part of the mask itself. These masks first became popular in the Toronto (Canada) healthcare community during the 2003 SARS Crisis. SARS was identified as being respiratory based and it was determined that conventional oxygen therapy devices were not designed for the containment of exhaled particles. Common practices of having suspected patients wear a surgical mask was confounded by the use of standard oxygen therapy equipment. In 2003, the HiOx80 oxygen mask was released for sale. The HiOx80 mask is a closed design mask that allows a filter to be placed on the exhalation port. Several new designs have emerged in the global healthcare community for the containment and filtration of potentially infectious particles. Other designs include the ISO-O2 oxygen mask,the Flo2Max oxygen mask, and the O-Mask. The use of oxygen masks that are capable of filtering exhaled particles is gradually becoming a recommended practice for pandemic preparation in many jurisdictions.

Because filtered oxygen masks use a closed design that minimizes or eliminates inadvertent exposure to room air, delivered oxygen concentrations to the patient have been found to be higher than conventional non-rebreather masks, approaching 99% using adequate oxygen flows. Because all exhaled particles are contained within the mask, nebulized medications are also prevented from being released into the surrounding atmosphere, decreasing the occupational exposure to healthcare staff and other patients.

Resuscitation/Specialized Devices

1. The bag-valve-mask (BVM) is used for patients in critical condition who are either breathing extremely inefficiently, or not breathing at all (respiratory arrest). An oxygen reservoir bag is attached to a central cylindrical bag, attached to a valved mask that administers almost 100% concentration oxygen at 8-15 lpm. The central bag is squeezed manually to deliver a “breath” to the patient, or assist them in inspiration by overcoming airway resistance or thoracic constriction. This is the standard administration method for acute respiratory distress or respiratory arrest.

2. The pocket mask is a small device that can be carried on one’s person. It is used for the same patients who the BVM is indicated for, but instead of delivering breaths by squeezing a reservoir, the care provider must exhale into the mask. Exhaled air from the provider can provide up to 16% oxygen to the patient, or higher if used with supplemental oxygen.

3. The anaesthetic machine is a machine used during anesthesia that allows a variable amount of oxygen to be delivered, along with other gases including air, nitrous oxide and inhalational anaesthetics.

4. Aviator type and other specialized tight fitting oxygen masks are used in hyperbaric oxygen chambers and to provide oxygen to carbon monoxide victims.

Related devices

1. A pressure regulator is used to control the high pressure of oxygen delivered from a cylinder to a low pressure controllable by the flowmeter.

2. A flowmeter is used to control and indicate the flow of oxygen. Typiclal flow range is 0-15 lpm.

3. A nebulizer can be used deliver nebulizable drugs such as albuterol or epinephrine into the airways by creating a vapor-mist from the liquid form of the drug. Nebulizers are also commonly used with room air in the home with an electric air pump.

Negative effects

Although most EMS jurisdictions hold that oxygen should not be withheld from any patient, there are certain situations in which oxygen therapy can have a negative impact on a patient’s condition.

Oxygen has vasoconstrictive effects on the circulatory system, reducing peripheral circulation and was once thought to potentially increase the effects of stroke. However, when additional oxygen is given to the patient, additional oxygen is dissolved in the plasma according to Henry’s Law. This allows a compensating change to occur and the dissolved oxygen in plasma supports embarrassed (oxygen-starved) neurons, reduces inflammation and post-stroke cerebral edema. Since 1990, hyperbaric oxygen therapy has been used in the treatments of stroke on a worldwide basis. In rare instances, hyperbaric oxygen therapy patients have had seizures. However, because of the afformentioned Henry’s Law effect of extra available dissolved oxygen to neurons, there is usually no negative sequel to the event. Such seizures are thought to be caused by hypoglycemia and the risk can be eradicated or reduced by carefully monitoring the patient’s nutritional intake prior to oxygen treatment.

Some jurisdictions require that oxygen should not be given to children or people suffering from certain long-term lung conditions by first-responders without medical consultation.

Oxygen first aid has been used as an emergency treatment for diving injuries for years. The success of recompression therapy as well as a decrease in the number of recompression treatments required has been shown if first aid oxygen is given within four hours after surfacing. There are suggestions that oxygen administration may not be the most effective measure for the treatment of DCI/DCS and that Heliox may be a better alternative. Recompression in a hyperbaric chamber with the patient breathing 100% oxygen is the standard hospital and military medical response to decompression illness and decompression sickness.

Oxygen should never be given to a patient who is suffering from paraquat poisoning unless they are suffering from severe respiratory distress or respiratory arrest, as this can increase the toxicity. (Paraquat poisoning is rare – for example 200 deaths globally from 1958-1978).

Oxygen therapy while on aircraft

In the United States, most airlines restrict the devices allowed on board aircraft. As a result passengers are restricted in what devices they can use. Some airlines will provide cylinders for passengers with an associated fee. Other airlines allow passengers to carry on approved portable concentrators. However the lists of approved devices varies by airline so passengers need to check with any airline they are planning to fly on. Passengers are generally not allowed to carry on their own cylinders. In all cases, passengers need to notify the airline in advance of their equipment.

“For me, the bottom line is now I can travel to Germany to visit my grandkids,” said Trixie Robinson, an oxygen patient in Carlsbad. “Before the Eclipse, I had to arrange for oxygen tanks wherever I was going. Now I just buy a plane ticket and go.”

Developed over five years at a cost of $12 million, the Eclipse weighs 17 pounds, has a retractable handle and wheels for mobility, and is about the size of a student’s backpack. It was designed to fit easily under standard airplane seats. Prior to the Eclipse, patients needing continuous flow oxygen were required to make arrangements for the delivery of multiple oxygen cylinders or to ship large stationary concentrators to their destination and pay extra fees for oxygen onboard the airplane.

In addition to oxygen patients, oxygen providers also stand to benefit from the FAA decision.

“Now, when we have a patient going on a long trip, we just give them an Eclipse,” said Jim Karls, President of Halprin, Inc., a provider in upstate New York. “The Eclipse gives us a simple solution to what used to be a very complicated logistical problem.”

The new Special Federal Aviation Regulation (SFAR 106) ruling that allows airline passengers to use their Eclipse onboard became effective on September 12, 2006.

“This is also good news for the airlines because of the light weight, portability and safety of the Eclipse when compared to cylinders,” said Jim Bixby, SeQual CEO. “The Eclipse runs on battery power and is the only portable concentrator with continuous-flow capability, the standard for long-term oxygen therapy patients. Also, it’s much quieter when compared to other concentrators – an important attribute for travelers.”

Vernon Pertelle, a member of the SeQual board who has more than 20 years experience in the field, most recently as corporate director of respiratory care and HME services at Apria Healthcare, said the approval marks a significant step in improving the quality of life for oxygen patients.

“They can be un-tethered from old technology and have their therapeutic needs met wherever they go — from home, to car, to RV, to train or airplane,” said Pertelle. “They now have a portable with both continuous and pulse flow – integral to meeting their needs.”

About SeQual Technologies Inc. Founded in 1991, SeQual offers a family of innovative products ranging from the 3 LPM (liter-per-minute) continuous flow portable Eclipseâ„¢ to its popular, compact, easy-to-use bedside 10 LPM unit. More than 80,000 oxygen systems in use today rely on SeQual’s proven technology. SeQual’s air separation systems are used for industrial applications such as water purification, oxygenation for aquaculture, producing feed gas for ozone generators, or for any other processes needing high-purity, dry oxygen or nitrogen on site. SeQual is a private company based in San Diego. For information on the Sequal Eclipse Portable Oxygen Concentrator