What is Hyperbaric Oxygen Therapy?

Hyperbaric oxygen therapy refers to the treatment of the entire body with 100% oxygen at greater than normal pressure. Patients sit in a pressurised chamber and breath oxygen through a mask or hood.

How does HBOT work?

Hyperbaric Oxygen works in the following ways:

  • Pressure effects of Oxygen
  • Vasoconstrictive effects of Oxygen
  • 100% oxygen concentration effects on the diffusion gradient
  • Hyperoxygenation of ischaemic tissue
  • Up regulation of growth factors
  • Antibacterial effects

Pressure Effects Of Oxygen


Any free gas trapped in the body will decrease in volume as the pressure on it increases. With a threefold increase in pressure, a bubble trapped in the body is reduced by two-thirds. This reduction in gas volume has been successfully applied to air embolism and decompression sickness. At elevated pressures the harmful effects of gas bubbles in the tissues are minimised.

Vasoconstrictive effects of oxygen

The vasoconstrictive effects of HBOT can be used to good effect to treat patients. HBOT causes significant reduction in swelling and oedema, which has been shown to be beneficial in reperfusion injury, crush injury, compartment syndrome, burns, wound healing and failing flaps.

Oxygen diffusion effects

The diffusion of nitrogen out of the tissues in decompression sickness is facilitated by the use of 100% oxygen. In wound healing the beneficial effects of oxygen are primarily related to the concentration of oxygen molecules in the tissues, rather than by diffusion kinetics. However the rate of oxygen entry into the wound environment is affected by the rate of diffusion from the capillaries. Oedema adversely affects the achievement of high oxygen concentrations in the wound and increases the intercapilliary diffusion distance. Even a small increase in tissue oedema can dramatically slow the rate of entry of oxygen into the tissues and can cause tissue hypoxia

Hyperoxygenation of tissues

The hyperoxygenation of hypoxic tissue is one of the key mechanisms by which HBOT accelerates wound healing. Numerous studies have shown a dose response curve for the provision of oxygen in the wound healing environment. Chronic wounds are normally hypoxic and the provision of HBOT reverses this. It then allows for the acceleration of the wound healing processes which continue long after the HBOT session has ended and tissue oxygen levels have returned to pre-treatment values. Over time the oxygenation of the chronic wounds improves with HBOT. It has been shown that for irradiated wounds, HBOT induces neovascularisation, which becomes significant after fourteen treatments and continues years after the HBOT has ceased.

Oxygen and Infection

Oxygen is the key to the phagacytosis and killing of bacteria by elements of the immune system. Increasing the concentration of oxygen over normal levels has been shown to reduce infection.

Side effects of HBOT

HBOT has a very good safety record, and the only side effects of note are ear and sinus barotrauma and reversible myopia.

We would not treat people with the following conditions:

  • Congestive heart failure
  • Untreated pneumathorax