UHMS Approved indications for Hyperbaric Oxygen AIR OR GAS EMBOLISM Air or gas embolism occurs when gas bubbles enter arteries, veins and/or capillaries. This results in reduced blood flow and oxygen delivery. If not fatal, gas embolism can result in severe, long-standing and irreversible physical and emotional disabilities. HBO2 has been shown to reduce the size of bubbles, push bubbles through capillaries into the veinous return to the  lungs, dissolve bubbles and reduce swelling from obstructed vessels that leak fluid into surrounding tissues. HBO2 treatment is the primary treatment for gas embolism and a major review of reported cases clearly indicates superior outcomes with its use compared to non-recompression treatment. CARBON MONOXIDE Carbon monoxide (CO) is a colorless, odorless gas produced as a byproduct of combustion. Poisoning occurs by inhalation, either accidentally or intentionally (suicide attempt). CO poisoning is responsible for an estimated 40,000 emergency department visits and 1,000 accidental deaths in the United States annually. Approximately 5-6% of patients evaluated in emergency departments for CO poisoning are treated with HBO2. CO binds to hemoglobin in red blood cells. HBO2, accelerates the clearance of CO from the body, restoring oxygen to sensitive tissues such as brain and heart. Research published in the past few years has demonstrated   other mechanisms of CO toxicity. Blood vessel injury from CO has been demonstrated to result from CO-induced production of nitric oxide-derived oxidants and cellular injury from activated white blood cells (neutrophils). CO also causes direct central nervous system cellular injury through mechanisms that include disturbance of energy metabolism and intracellular production of oxygen free radicals. In animal experiments, HBO2, but not normobaric oxygen (NBO2), has been demonstrated to block each of these mechanisms of toxicity. CLOSTRIDIAL MYOSITIS & MYONECROSIS (GAS GANGRENE) Clostridial myositis and myonecrosis is an acute, rapidly progressive infection of the soft tissues commonly known as “gas gangrene.”  The infection is caused by one of several bacteria in the group known as “clostridium.”  While over 150 species have been identified, only a few commonly cause gas gangrene.  The infection typically spreads from a discrete focus of clostridium within the body.  The source can actually be within the body, as clostridium normally live in the gastrointestinal tract.  Alternatively, the infection can originate outside the body, such as contamination of wounds during trauma (e.g. motor vehicle accidents). Gas gangrene is severe and can advance quickly.  Besides replicating and migrating, the organisms produce poisons known as exotoxins.  Exotoxins are capable of liquefying adjacent tissue and inhibiting local defense mechanisms.  Clostridium bacteria are “anaerobic,” meaning that they prefer low oxygen concentrations.  If clostridium are exposed to high amounts of oxygen, their replication, migration, and exotoxin production can be inhibited.  This is the rationale for the use of HBO2 in the treatment of gas gangrene.  Repeated treatment in the hyperbaric chamber has the potential to slow the progress of the infection while the two primary therapies, antibiotics and surgical resection of infected tissue, control it. The advantages of HBO2 are two-fold.  First, it may be life-saving because exotoxin production is rapidly halted and less heroic surgery may be needed in gravely ill patients.  Second, it may be limb and tissue-saving, possibly preventing amputation. CRUSH INJURY Crush injuries occur when tissues are severely traumatized such as in motor vehicle accidents, falls, and gun shot wounds.  When crush injuries are severe, the complications such as infection, non-healing of fractures, and amputations range up to 50%. When used as an adjunct to surgery and antibiotics, HBO2 therapy is a way to reduce these complications.  HBO2 treatments should be started as soon after injury as possible.  They are usually continued for 5 to 6 days.  A number of related conditions, including compartment syndromes, thermal burns, and threatened replantations are also benefited by HBO2. DECOMPRESSION SICKNESS and ARTERIAL GAS EMBOLISM When scuba diving, additional oxygen and nitrogen dissolve in tissues.  The additional oxygen is consumed, but the excess nitrogen must be breathed out during decompression. During or after ascent excess nitrogen can form bubbles, analogous to the carbon dioxide bubbles that form when a carbonated beverage container is opened.  These bubbles if large enough can cause decompression sickness (“DCS” or “the bends”).  Trapping of gas within the lungs during ascent, either because the lung is diseased or because of breath-holding, can force bubbles into the bloodstream (“arterial gas embolism” or “AGE”), where they can block the flow of blood or damage the lining of blood vessels supplying critical organs such as the brain. Symptoms of DCS or AGE can include joint pain, numbness, tingling, skin rash, extreme fatigue, weakness of arms or legs, dizziness, loss of hearing, and in serious cases, complete paralysis or unconsciousness. ENHANCEMENT OF HEALING IN SELECTED PROBLEM WOUNDS Problem wounds fail to respond to established medical and surgical management. Such wounds usually develop in compromised hosts with multiple factors contributing to inhibition of tissue repair. These include diabetic feet, compromised amputation sites, non-healing wounds, and ulcers due to poor circulation. All share the common problem of low tissue oxygen, usually related to impaired circulation. Diabetic foot wounds are one of the major complications of diabetes and an excellent example of the type of  wound which can be treated with HBO2. Fifty percent of all lower extremity amputations in the United States are due to diabetes, at a cost of more than one billion dollars per year. EXCEPTIONAL BLOOD LOSS - ANEMIA Exceptional blood-loss anemia is the loss of enough red blood cells to compromise oxygen delivery to tissues in patients who cannot be transfused for medical or religious reasons.  Medical reasons include the threat of blood product incompatibility or concern for transmissible disease.  Religious beliefs may prohibit the receipt of transfused blood products. Red blood cells (RBCs) contain hemoglobin (Hb).  Hemoglobin accepts oxygen as RBCs pass through the lungs. If plasma were the only vehicle to deliver dissolved oxygen, each 100 ml of blood would carry 0.3 ml of gaseous oxygen.  The consumption of oxygen by human tissues far exceeds this.  For instance, the kidney extracts 2 ml of oxygen for every 100 ml of blood.  From the same 100 ml of blood, the brain extracts 6.5 ml and the heart 10.5 ml. In most instances, humans average 15 grams of hemoglobin per 100 cc of blood.  Each gram of hemoglobin transports 1.34 ml of oxygen.  This is in addition to the oxygen carried by plasma.  So, 100 ml of blood, by containing 15 grams of hemoglobin, can carry about 20 ml of gaseous oxygen. In the 1960s, the Dutch thoracic surgeon Boerema demonstrated that one could exchange transfuse piglets with a simulated plasma mixture of buffered normal saline (Ringer’s Lactate solution), dextrose and dextran.  In this process, blood was removed from the blood vessels and the substitute liquid (without hemoglobin) replaced.  He then pressurized the piglets in a chamber while the animals breathed 100% oxygen.  By this means enough oxygen could be dissolved in the simulated plasma to meet tissue oxygen requirements.  This was enough to sustain the animal, as evidenced by the fact that the animals survived and could be brought out of the chamber to be successfully re-exchange transfused with their previously extracted blood. As oxygen administered for long periods can become toxic, intermittent administration of HBO2 is essential. The American thoracic surgeon, George Hart, in 1974, reported a series of 26 severe blood loss patients who were treated with HBO2 as an alternative to red blood cell transfusion.  The survival rate was 70%. INTRACRANIAL ABSCESS Abscess formation in the brain can be a devastating complication of sinus infections or bone infections (osteomyelitis) of the skull. Occasionally, abscesses are seeded from infection occurring in other parts of the body. Brain abscesses are frequently multiple. One of the problems in treatment relates to the fact that surgically drainage is often required. Unfortunately, normal brain tissue surrounding the abscess may be unavoidably damaged by such surgery. Fine needle aspiration of the abscesses is being performed with greater frequency to avoid this problem. Antibiotics may not penetrate well into brain abscesses. Furthermore, white blood cells, which kill infecting bacteria, may not have enough oxygen to eliminate the infection when functioning at a distance from the blood supply. Most intracranical abscesses are caused by anaerobic bacteria (bacteria that function optimally in low oxygen concentrations). HBO2 raises the environmental oxygen level in the region of the abscess, exposing the bacteria to levels which may inhibit or kill them. The average mortality from intracranial abscess reported in six large series was 20% when HBO2 was not used. Among the 48 known cases treated with HBO2 to date, the mortality has been only 2% with less apparent brain damage. NECROTIZING SOFT TISSUE INFECTIONS A number of  infections of soft tissue may benefit from adjunct treatment with HBO2 and are included in the category of “necrotizing infections.”  Names of such clinical syndromes include crepitant anaerobic cellulitis, progressive bacterial gangrene, necrotizing fasciitis, and nonclostridial myonecrosis.  Gas gangrene (Clostridial myositis and myonecrosis) is considered a separate entity. Necrotizing soft tissue infections may result from either a single strain or a mixed population of bacteria, typically occurring after trauma, surgery, and/or around foreign bodies.The individual affected is frequently compromised by conditions such as diabetes or vascular disease. The infections commonly lower tissue oxygen levels, impairing the ability of the white blood cells (neutrophils) to fight infection.  Toxins may also inhibit neutrophil activity. The primary treatments for necrotizing soft tissue infection are surgical excision and appropriate antibiotics.  In selected cases, addition of HBO2 may be lifesaving.  HBO2 may be beneficial in several ways.  Some of the bacteria involved are “anaerobic,” growing most rapidly in a low oxygen environment.  In the hyperbaric chamber, tissue oxygen levels may be raised sufficiently to inhibit bacterial growth.  In addition, HBO2 may enhance the ability of neutrophils to kill bacteria, by a number of different mechanisms. The use of HBO2 for treatment of necrotizing soft tissue infections should be individualized.  In specific instances where risk of morbidity and mortality are high, adjunct HBO2 should be considered. REFRACTORY OSTEOMYELITIS  Refractory osteomyelitis is a bone infection which has not responded to treatment.  HBO2 increases the oxygen concentration in infected bone.  HBO2 directly kills or inhibits the growth of organisms which prefer low oxygen concentrations (strict anaerobes).  Conversely, HBO2 has no direct effect on organisms which prefer high oxygen concentrations (aerobes).   When HBO2 increases the oxygen tension in infected tissue, however, the oxygen-dependent killing mechanisms of the polymorphonuclear leukocyte are provided sufficient oxygen to function.  Thus, HBO2 treatment provides the necessary substrate (oxygen) for the killing of aerobic organisms by white blood cells. HBO2 also augments the efficacy of bacterial killing by certain antibiotics (aminoglycosides, vancomycin, quinolones and certain sulfonamides).  HBO2 provides adequate oxygen for fibroblast activity, cells which promote healing in hypoxic tissues.  Finally HBO2 prevents polymorphonuclear leukocytes from adhering to damaged blood vessel linings.  This decreases the degree of inflammation which may accompany the surgical treatment of refractory osteomyelitis.             HBO2 is adjunctive therapy and is used with appropriate antibiotics, surgery and nutrition.   HYPERBARIC OXYGEN TREATMENTS FOR COMPLICATIONS OF RADIATION THERAPY One-half of the estimated 1.2 million new cases of invasive cancer will receive radiation therapy as a part of their treatment. Radiation is very toxic, especially when combined with chemotherapy. Some people are more sensitive to radiation than others, and there are no reliable tests available as yet to identify those patients who will experience the worst side effects. Most radiation specialists or oncologists design their treatments to give the best tumor control and still have no more than 5% of patients develop severe reactions to treatment. Radiation side effects are generally divided into two categories. First, there are those that happen during or just after the treatment, called acute reactions. Second, there are those that happen months or even years after the treatment, called chronic complications. The acute side effects almost always resolve with time and are treated in such a way as to address the patient’s symptoms. Fortunately, normal tissue cells have excellent repair abilities and within a few weeks after the completion of radiation, this damage is repaired. In the meantime, the patient is supported with pain medicine and supplemental nutrition. Chronic complications are likely to get worse. Almost all chronic radiation complications result from scarring and narrowing of blood vessels. If this process progresses death or necrosis of these tissues can occur. Chronic radiation damage is called "osteoradionecrosis" when the bone is damaged and "soft tissue radionecrosis" if it is muscle, skin or internal organs which have been damaged by the radiation. Since the 1970’s, surgeons of the head and neck region have come to recognize the value of HBO2 in treating damage of the jaw bone due to radiation. HBO2 has had some of its most dramatic successes in treating or preventing damage to the jaw bone as a result of radiation treatments. It has now also been applied to damage of the brain, damage of muscle and other soft tissues of the face and throat, damage to the chest wall, abdomen and pelvis as a result of radiation treatment. Papers in medical journals also report success in treating damage to the bladder and intestines due to radiation. The high dose oxygen provided in the hyperbaric chamber is carried in the patient’s circulation to the site of injury to be available for repair of the damage done by the narrowing and scarring of the blood vessels. Each treatment typically takes one to two hours, and usually 30-40 daily treatments are needed for healing radiation damage.  SKIN GRAFTS AND FLAPS (COMPROMISED) Reconstructing complex wounds is accomplished by shifting or transferring tissues to the wound from a different part of the body.  A “skin graft” is the transfer of a portion of the skin (without its blood supply) to a wound.  A “flap” consists of one or more tissue components including skin, deeper tissues, muscle and bone.  Flaps are transferred with either their own blood supply (pedicle flap) or with detached blood vessels which are attached at the site of the wound (free flap). Skin grafts survive as oxygen and nutrients diffuse into them from the underlying wound bed.  Long-term survival depends on a new blood supply forming from the wound to the graft.  When the wound bed does not have enough oxygen supplied to it, the skin graft will fail.  Common causes for this are previous radiation to the wound area, diabetes mellitus, and certain infections.  In these situations, the availability of oxygen in the wound bed can be increased with HBO2 in preparation for skin grafting.  Additionally, HBO2 can be used after skin grafting to increase survival. THERMAL BURNS In closed space fires, thermal and smoke (products of combustion) damage to the lungs can occur, requiring in intubation and use of a mechanical ventilator. Burn injuries characteristically progress to become deeper and more extensive with time. Peak damage occurs within 3-4 days, and can be 10 times worse than the initial burn. In more severe and/or extensive burns (deep second, third and fourth degree burns), multiple aggressive surgeries are necessary to excise the burned tissue and later perform skin grafts to cover these areas. Adjunctive HBO2 has been shown to limit the progression of the burn, reduce swelling, reduce the need for surgery, diminish lung damage, shorten the hospitalization, and save money. These benefits are more apparent if therapy is initiated within 6-24 hours of the burn. Ideally, the patient should have 3 sessions in the first 24 hours, twice daily treatments until the process stabilizes, then continued therapy as indicated for healing enhancement and to support grafts. Indications for HBO2 typically include deep second-degree and third-degree burns that involve greater than 20% of the total body surface area, and less extensive burns that involve the face, hands or groin area. Best results are realized when HBO2 is used as an integral part of a multidisciplinary approach.