Hyperbaric Medicine
Technical Information

About Hyperbaric Oxygen Therapy
Hyperbaric oxygen (HBO2) therapy is a medical treatment for specific indicated conditions, in which 100 percent oxygen is administered at a pressure greater than sea level.

HBO2 is a currently accepted therapy in the resolution of certain critical care situations such as carbon monoxide poisoning, decompression sickness, gas embolism, clostridial myonecrosis and other necrotizing infections involving mixed organisms. The use of adjunctive hyperbaric oxygen therapy in treatment of chronic refractory infections and radiation necrosis of either bone or soft-tissue is well accepted. Early adjunctive HBO2 therapy has also been found to be of benefit in preparation and preservation of compromised skin grafts or flaps.

Primary Mechanisms of Action

HYPEROXYGENATION: Increased oxygenation provides immediate support to poorly perfused tissue in areas with compromised blood flow. During a treatment, arterial pO2 of 2,200 mm Hg and tissue pO2 of 250 mm Hg can be achieved. This is an interim measure until angiogenesis occurs and/or vascular surgery can re-establish adequate tissue perfusion. In the event of carbon monoxide poisoning, hyperoxygenation causes the rapid dissociation of CO molecules from hemoglobin and cytochrome A3 oxidase, while delivering dissolved oxygen to hypoxic tissue.

VASOCONSTRICTION: HBO2 acts as a potent vasoconstrictor without significantly reducing oxygenation. This effort is useful in reducing interstitial edema in skin flaps and grafts, and controlling compartment pressures in crush injuries. HBO2 involvement in burn therapy has shown up to a 30 percent decline in fluid requirements, faster healing of ischemic tissue, a decreased need for skin grafting and a reduction in hospital length of stay.

ANTIMICROBIAL EFFECT: Hyperbaric oxygen is bacteriocidal to strict anaerobic organisms and seems to also be effective against many microaerophilic organisms. Polymorphonuclear cells in low oxygen tensions (e.g., five to 15mm Hg) show diminished ability to kill organisms through the peroxidase system (an oxygen-dependent mechanism). The killing ability of white blood cells can be greatly enhanced by increasing tissue oxygen tensions. Other bacteriologic effects of HBO2 are due to toxin exhibition or inactivation, which has been demonstrated in treatment of gas gangrene.

DIRECT PRESSURE: HBO2 is used for reduction in gas bubble size, which makes it primary treatment for decompression illness from diving accidents and air embolism resulting from iatrogenic causes in the clinical setting.

Secondary Mechanisms of Action(These effects are indirect and delayed.)

FIBROBLAST PROLIFERATION: Nonhealing tissues are often hypoxic. Raising the tissue oxygen tension will stimulate fibroblast activity. Tissue oxygen tensions of 30 to 40mm Hg are necessary for fibroblast proliferation, collagen synthesis and development of a collagen matrix to support capillary budding into avascular areas.

NEOVASCULARIZATION: The restoration of low pO2 to physiological levels will result in capillary proliferation. This can aid in the preparation of a vascular bed for skin or bone grafting in osteoradionecrosis, the infected open amputation stump and refractory osteomyelitis.

OSTEOGENESIS: The osteoclastic function is critical in the removal of necrotic bone and has been found to be oxygen dependent. HBO2 therapy has been shown to be a principle factor in promoting effective osteoclastic stimulation. This can achieve valuable results in managing osteomyelitis and osteoradionecrosis.

THE HYPERBARIC MEDICINE DEPARTMENT
As part of PMCC's Level 3 Trauma Center, we are available for emergencies 24 hours a day, seven days a week. Standard hours of operation for the department are from 7a.m. until 5:30 p.m.(cst). Monday through Friday. The department is under the medical direction of physicians trained in hyperbaric medicine and operations. Our department is also staffed with critical care nurses and certified hyperbaric technologists specifically trained in the medical, physical and technical aspects of HBO2.

We have a computer controlled, air pressurized, 18 person, walk-in hyberbaric chamber. For most treatments, the chamber is pressurized to 2.4 atmospheres absolute. The patient breathes 100 percent oxygen via a head hood, mask or endotracheal tube. A single person, oxygen pressurized, monoplace chamber is also available for certain cases and educational purposes.

TREATMENT PROTOCOL
Treatment times vary according to condition, but most therapies are for one to two hours once or twice daily. In some cases, treatments are every eight hours until the acute process is resolved. Generally, acute conditions are treated less than 10 days and chronic conditions may require 30 or more treatments.

CONSULTATION
HBO2 therapy is provided on an inpatient or outpatient basis, depending on the patient's condition. HBO2 therapy is offered as a referral and consultation service only. While undergoing treatments, the patient remains under the primary care of the referring physician. Out-of-town patients may be referred to an appropriate local physician at the discretion of the attending physician. Follow-up and evaluation reports, including photographs when appropriate, will be provided to all referring physicians.

INTEGRATED RESOURCES
The Carraway wound treatment program is dedicated to management of chronic non-healing wounds. Their team consists of surgeons, infectious disease and emergency medicine physicians. Along with skilled nurses and technicians, they provide a comprehensive approach to care which includes:

> Debridement
> Non-invasive Vascular Studies
> Growth Factors (Procuren®)
> Infection Control
> Grafting
> Compression Therapy
> Hyperbaric Oxygen Therapy

Physicians Medical Center Carraway provides home health care which is consistent with its case management and managed care modules.

ACCEPTED INDICATIONS/INSURANCE COVERAGE
The following conditions have been identified as accepted indications for primary or adjunctive use of HBO2 by the Hyperbaric Oxygen Therapy Committee of the Undersea and Hyperbaric Medical Society. In most cases, insurance coverage is provided by Medicare, Medicaid, Blue Cross and other third party carriers.

1. Air or gas embolism.
2. Carbon monoxide poisoning and smoke inhalation. Carbon monoxide complicated by cyanide poisoning.
3. Clostridial myonecrosis (gas gangrene).
4. Crush injury, compartment syndrome and other acute traumatic ischemia.
5. Decompression sickness.
6. Enhancement of healing in selected problem wounds.
7. Exceptional blood loss (anemia).
8. Necrotizing soft tissue infections (subcutaneous tissue, muscle, fascia).
9. Osteomyelitis (chronic refractory). Unresponsive to conventional medical and surgical management.
10. Radiation tissue damage (osteoradionecrosis and soft tissue radionecrosis).
11. Skin grafts and flaps (preparation and preservation of compromised tissue).
12. Thermal burns.
13. Adjunctive hyperbaric oxygen in intercranial abscess.

Contraindications

Absolute
Untreated Pneumothorax

Relative
Upper Respiratory Infection
Chronic Sinusitis
Ear Surgery
Seizure Disorders
Emphysema (CO2 Retention)
History of Spontaneous
Pneumothorax
History of Thoracic Surgery
Viral Infections
High Fever
Congenital Spherocytosis
Optic Neuritis
Cataracts

Side Effects (potential)
Ear & Sinus Barotrauma
Visual Changes
Grand Mal Seizures
Pulmonary Toxicity

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