Analysis
Decompression Sickness
Decompression sickness is due to nitrogen bubble formation in tissue, usually associated with rapid ascent from diving depth without proper subsurface decompression stops. The mechanism of bends formation (caused by decompression sickness) is reviewed below.
- Nitrogen gas tissue loads with depth and on-gassing occurs with the set. Off gassing on ascent.
- If there is Ascent from depth faster than bubble-free tissue off gassing will allow — bubbles will form.
- Resultant Bubble formation is in veins and soft tissues.
- Endothelial (vessel wall) damage occurs with clots, ischemia, and more. HBO is the treatment of choice.
- HBO results include pressure bubble reduction & O2/N2 gradient for gas defusion. HBO also prevents reperfusion injury (white blood cell adherance to blood vessel walls).
Arterial Gas Embolism
Arterial Gas Embolism (AGE) is caused by gas bubbles in the circulatory system. AGE or arterial gas embolism is a common complication of two divergent conditions:
Post Diving in which there is rapid ascent. Air expands in the pulmonary alveoli. If air expands faster than can be ventilated the alveolar wall will expand forcing air directly into the capillaries surrounding the alveoli. Gas forms bubbles that travel in the systemic circulation where they will eventually occlude the vessel when the arteries/arterioles narrow. This will cause an area of occlusion and stroke symptoms if it occurs in the brain. Common presentation of CNS or brain AGE is stroke and seizure.
Iatrogenic or Medical procedure complications. The mechanism here is arterial gas which is associated frequently with arterial lines and arterial procedures such as angiography. . Arterial gas emboli are associated with medical procedures which include the procedures of laparoscopy, cardiac bypass surgery, fine needle lung biopsy, angiography, and the use of pressure cement guns and hip surgery.
Central nervous system AGE is far more common than the average medical practitioner recognizes. A stroke occurring during a medical procedure should be considered a possible arterial gas embolism until proven otherwise. A CT scan may show air or gas in the arteries of the brain. Treatment for this condition is HBO compression therapy for bubble reduction and gas diffusion.
Diabetic Foot Wounds
Diabetes is the leading cause of limb amputation in the world. Diabetic foot wounds are usually complicated by infection and low oxygen tensions. Hyperbaric oxygen attacks these problems directly, providing the necessary substrate (O2) to enhance the body’s ability to fight infection and provide the oxygen necessary for limb salvage. Amputations can be reduced by 95%.
Thermal Burns
Thermal burns are a major injury. Larger burns have a very high mortality. Death from burns is related to infection, respiratory failure, wound sepsis. Therapy of burns is directed toward reducing edema, preserving marginable viable tissue in the zone of stasis, protecting the microvasculature, enhancing host defenses, and providing the essential substrate to maintain viability (oxygen). The goals of burn therapy include survival of the patient, rapid wound healing, minimization of scarring and abnormal pigmentation, and cost effectiveness. Optimal outcome is restoration, as nearly possible, to the pre-burn quality of life. Hyperbaric oxygen attacks these problems directly and results in a reduced need for grafting, reduced need for hospital stay, and reduction of scarring.
Necrotizing Soft Tissue Infections
Necrotizing fasciitis and gas gangrene are both characterized by low oxygen tensions. Hyperbaric oxygen can provide a barrier to extension of these wounds and prevent loss of limbs or disfiguring surgery.
Acute Peripheral Ischemia
Caused by interruption of circulation in a number of medical conditions that result in low oxygen tensions and potential acute loss of limb.
Central Retinal Artery Occlusion
Interruption of blood flow to the retinal arteries can cause acute blindess. This is a true medical emergency and hyperbaric, oxygen as an adjunct to traditional care is warranted.
Compromised Flaps and Grafts
In tissue compromised by radiation or in other cases where there is decreased perfusion or hypoxia, hyperbaric oxygen therapy has been shown to increase flap salvage.
Crush Injuries
Crush injuries result from trauma and typically result in injury to multiple tissues from skin and subcutaneous tissue to muscle and tendons, bones and joints. Predictable compliciations are osteomyelitis, nonunion fractures, failed flaps, and amputations; and these occur in about 50% of patients using usual and standard medical interventions. Hyperbaric oxygen can support hypoxic tissue, reduce swelling, and mitigate reperfusion injury resulting in less tissue damage and limb salvage.
Radiation Soft Tissue and Bony Necrosis
More than 600,000 patients receive radiation for malignancy. Serious radiation complications occur in up to 16% of survivors. Radiation injury is characterized by low oxygen tensions and subsequent loss of vascularity. Hyperbaric oxygen provides a stimulus to new vessel formation and the provision of oxygen to these compromised tissues. An additional benefit is migration of stem cells to the area of involvement resulting in healing and enhancement of the safety of surgery in previously irradiated tissues. It should be considered in cases of radiation injury.
Carbon Monoxide Poisoning
One of the leading causes of death from poisoning throughout the world. Carbon monoxide can damage the brain, the heart, or any organ system. It’s rapid removal from the red blood cells and plasma can limit damage and prevent long-term problems or death. Any period of unconsciousness is cause to consider hyperbaric oxygen therapy.
This is not a complete list of disease entities that benefit from hyperbaric oxygen therapy. For further information consult the Undersea and Hyperbaric Medical Society, www.uhms.org.