Hyperbaric Oxygen Therapy
Hyperbaric Oxygen Therapy (HBOT) can be defined as a treatment during which a patient breathes 100% oxygen whilst inside a treatment chamber at a pressure higher than at sea level (1 atmosphere absolute).
Current information indicates that pressurization should be at least 1.4 atmospheres absolute (ATA) or higher to an effective treatment for Undersea and Hyperbaric Medical Society (UHMS) approved indications.
Breathing 100% oxygen at increased atmospheric pressure of 2-3 ATA causes oxygen to be dissolved in the blood plasma and greatly increases its availability to the body's tissues and cells. In this way the oxygen concentration can be increased to 10-15 times the amount achieved on breathing air.
Oxygen Administration
Oxygen is administered to the patient using either a breathing mask or a hood. The hoods are made of a clear soft plastic and are sealed at the neck. Whilst in the chamber the patients may read, listen to music, or watch television/movies.
Physiological Effects of HBOT
Hyper oxygenation and increasing oxygen tension
Oxygen breathed at increased atmospheric pressure causes the oxygen to enter into solution in the blood plasma, bypassing erythrocytes and haemoglobin as the primary method of oxygen transport. Areas of the body compromised by poor circulation or injury then have an increased amount of oxygen available at a tissue/cellular level.
Angiogenesis /Neovascularisation
Increased oxygen stimulates the growth of new blood vessels in compromised areas.
Osteogenesis
HBOT may stimulate the production of new bone cells in compromised sites and osteoclast removal of dead bone is oxygen dependant.
Microbiological/Bactericidal
High levels of oxygen are toxic to anaerobic bacteria. The action of HBOT on clostridia is based on forming 02 free radicals in the relative absence of free radical degrading enzymes, such as superoxide dismutase, catalases, and peroxidases. In addition, HBOT speeds demarcation of non-viable tissue.
Vasoconstriction
Oxygen causes the constriction of blood vessels which can assist in the rapid reduction of oedema.
Bubble reduction
HBOT is the primary treatment modality treating pressure related conditions such as Decompression Illness (DCI) and Arterial Gas Embolism (AGE) where the physical size of gas bubbles is mechanically reduced by increased pressure.
Applications for HBOT
The uses of hyperbaric oxygen therapy are considerable and vary widely from country to country. HBOT may be used as a primary or adjunctive treatment in many conditions however the Undersea and Hyperbaric Medical Society (UHMS) officially recognizes 13 indications for which hyperbaric oxygen has been accepted to be effective:
- Decompression Sickness/Illness (DCS/DCI)
- Air or Gas Embolism (CAGE/AGE)
- Carbon Monoxide Poisoning
- Cloistridial Myositis and Myonecrosis (Gas Gangrene)
- Crush Injury, Compartment Syndrome and Other Acute Ischemia
- Enhancement of Healing in Selected Problem Wounds
- Exceptional Anaemia
- Intracranial Abscess
- Necrotising Soft Tissue Infections
- Osteomyelitis (Refractory)
- Delayed Radiation Injury (Soft Tissue and Bony Necrosis)
- Skin Grafts and Flaps
- Thermal Burns
Main indications of relevance to the use of HBOT in Christchurch
Diabetic Ulcers
Several prospective randomised trials of HBOT for diabetic ulcers have now been published. 4-8 All show improved healing and in four, a reduction in major amputation rate was reported .Follow-up studies suggest these benefits are maintained in the medium to long term (three to five years).9 Improved healing rates and an approximate halving of major amputation rates has been reported consistently in several other partly or non-randomised clinical studies and case series.9-11 A recent Cochrane review identified the need for further large randomised studies to validate this data, but concluded that, where it is available, HBOT should be administered for diabetic ulcers.
Traumatic Non Healing Wounds
ACC has approved HBOT for selected problem wounds that fail to respond to established medical and surgical management. Their scientific committee found that evidence supports the use of HBOT in vascular insufficiency ulcers, compromised amputation sites, non- healing traumatic wounds and diabetic feet.
Emerging Applications
At O2 Health in Christchurch we are extremely excited about researching the new applications for this new therapy in treating some very difficult conditions such as fibromyalgia, chronic fatigue syndrome and autism.
