23 June 2006

Hyperbaric Oxygen Therapy

This article gives detailed information on Hyperbaric Oxygen Therapy.

Hyperbaric Oxygen Therapy (HBOT) is an effective treatment that makes use of increased oxygen concentrations at an elevated atmospheric pressure, to assist in resolving various conditions, by a variety of mechanisms including: reduction of swelling, provision of oxygen for metabolism, fighting bacterial infection and speeding up cell repair.

The maximum pressures that HBOT uses are equivalent of up to three atmospheres. Oxygen becomes too toxic at higher pressures. The average temperature inside a decompression chamber is approximately 26 degrees Celsius.

How treatment is done
Treatment is best carried out in a multi-place chamber, as an attendant can provide full, personal care for the patient. As the chamber is pressurised, patients will experience similar sensations to that of flying, where the ears become blocked. Once the chamber is fully pressurised at the required depth, oxygen is breathed through a mask or hood.

Depending on the pressure, a combination of air, heliox and pure oxygen are used. In many cases, for example, decompression sickness, 100% oxygen is used intermittently during treatment.

Treatment increases total blood oxygen pressure to over 50 times normal. This to a great extent improves the delivery of oxygen to damaged tissues.

HBOT is not painful or unpleasant. Treatment is given in a friendly and relaxed environment. Depending on the size of the chamber, there are armchairs available for patients in which to relax. There may also be wheelchairs and hospital trolley beds available in the chamber.

In order to receive HBOT, a patient needs to be referred by their GP, specialist or healthcare professional. There are certain concerns with regards to patients who have cerebral palsy, brain injury, or those who have suffered a stroke. The reason for this is due to lack of scientific evidence of the effectiveness of HBOT with such patients.

HBOT and decompression sickness
In the case of decompression sickness (The Bends), divers enter the chamber and are treated according to a table of developed diving schedules. HBOT mimics the underwater environment (high pressures) by returning the diver to below surface level, and resuming the ascent to normal atmospheric pressure in stages, by slowly decreasing the pressure, thereby forcing nitrogen bubbles to be reabsorbed into bodily tissues, and then slowly allowing it to seep out.

Treating decompression sickness is a long and complicated process if performed underwater, due to restrictions that are placed on effective supervision and monitoring of the patient. Treatment is done according to preset diving tables, with systematic time and gradual depth changes until the diver is equalised.

During treatment, the patient breathes 100% oxygen with a mask. The oxygen speeds up the process whereby the body will flush out nitrogen bubbles. The oxygen will also saturate the damaged areas of the body to accelerate cell repair. Treatment lasts several hours, and requires qualified and experienced staff, and a diving medical practitioner to ensure the best results.

Treatment for decompression sickness can be anything between a four hour session, to several days of continuous treatment in unusual circumstances. Follow up therapy is essential.

With regards to diving, the problem with HBOT is that many a time, treatment is situated far from the location where incidents take place. If a diver is suffering with decompression sickness, they need to be taken to a treatment facility as soon as possible. Due to the pressure laws, flying an aeroplane could be detrimental to the diver as the high altitudes could create more nitrogen bubbles in the diver’s body.

Other conditions treated with HBOT
HBOT is not only used to treat diving injuries, but many other ailments as well. It is internationally recognised by healthcare funders and the South African Hyperbaric and Undersea Medical Association (SAHUMA) as an effective treatment for the following conditions:

  • Barotrauma and Decompression sickness
  • Carbon monoxide poisoning
  • Gas gangrene
  • Crush injury, compartment syndrome and other acute traumatic ischaemias
  • Brain abscess
  • Anaemia (acute blood loss)
  • Specific bone infections
  • Problem wounds
  • Delayed radiation injury (soft tissue and bony necrosis)
  • Thermal burns
These conditions have good supporting data, an understood mechanism of action and a positive cost-benefit ratio (for the man/woman in the street). Conditions such as acceleration of sports injuries may still be effective, but would only have beneficial cost-benefit ratios for a professional sport person.

Carbon monoxide poisoning and HBOT
Many patients who have suffered carbon monoxide poisoning as a result of an accident involving a fire, or inhaling smoke at factories, can also be treated by means of HBOT. The treatment has been clinically proven to be one of the most effective treatments for the condition, leading to outstanding results.

Carbon monoxide attaches to the haemoglobin of cells and mutates them by starving the cells of oxygen, often leading to coma, brain damage, and in many cases, death. HBOT is used to force off carbon monoxide molecules from the haemoglobin.

The treatment also helps by speeding up the production of new cells, and accelerating the healing process of damaged cells and growth of new blood vessels.

(Health24, June 2006)

Source: Jos Beer, Safety and Training Manager, Cape Diving (Pty) Limited

Source: Dr Jonathan Rosenthal, Hyperbaric Physician, Diving Medical Examiner

Source: National Hyperbarics, Kingsbury Hospital, Claremont, Cape Town

Reviewed by Dr Jonathan Rosenthal, Hyperbaric Physician, Diving Medical Examiner

Read more:
Decompression sickness
10 tips for diving survival


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