This week we respond to a GP requesting information about hyperbaric oxygen therapy for wound healing. Read on, this is interesting …
Hyperbaric Oxygen Therapy
for
Wound Healing
What’s hyperbaric oxygen therapy
Hyperbaric oxygen therapy (HBOT) delivers oxygen to the body in amounts and pressures greater than normal atmospheric oxygen for the treatment of a range of medical conditions. For example, it is an established treatment for decompression sickness (the bends’). In wound management, HBOT increases oxygen supply to wounds which may speed healing.
What sort of wounds are treated with HBOT?
HBOT is used to treat a range of wounds with diverse underlying causes. This includes chronic wounds which take a long time to heal, do not heal, or heal and recur. Different types of ulcers can be treated. This includes pressure ulcers, venous, arterial or mixed ulcers (poor blood circulation), as well as diabetic or neuropathic ulcers can also be treated. HBOT can be used to treat post-surgical wounds, soft tissue infections, thermal burns, wounds arising from radiation treatment, skin grafts and flaps at risk of tissue death, traumatic wounds such as crush injuries and diabetes-related wounds (eg diabetic foot conditions).
How do wounds heal?
Wound healing consists of three overlapping phases. The first of these, the inflammatory phase occurs 2 to 5 days immediately after a wound occurs. Cellular changes such as increased tissue oxygenation assist healing, white blood cells fight infection and wound repair begins. Next is the proliferative phase, from 2 days to 3 weeks after injury, which involves tissue growth and rebuilding. New tissue grows to cover the wound and the wound gets smaller. The final phase, the maturation and remodelling phase, occurs around 3 weeks to 2 years. At this time, the wound is closed and forms a scar which may disappear completely. Deeper wounds are more likely to have a lasting scar. The extent and duration of the phases is determined by the nature and severity of the wound. Small wounds heal quickly, while larger or deeper wounds take longer to heal.
How does HBOT help wound healing?
Wounds require (cellular) oxygen to heal. Exposing a wound to 100% oxygen assists wound healing in several ways and may speed up healing.
HBOT increases oxygen supply to the body, super-saturating tissues and haemoglobin in a process called hyperoxygenation. HBOT constricts blood vessels, reduces tissue swelling, and concurrently increases oxygen supply to tissues promoting collagen growth and tissue growth. Collagen is an important factor in tissue growth, as it contributes to scar tissue formation and stabilises skin as it grows over wounds. Tissues such as skin, muscles and other soft tissues grow faster in an oxygen rich environment. Oxygen therapy also stimulates white blood cells to kill bacteria and improves antibiotic activity.
How is HBOT delivered?
HBOT is usually an outpatient procedure and takes around two hours. It involves breathing 100% pure oxygen, at a pressure greater than normal atmospheric pressure (usually two to three times normal pressure). The air we normally breathe contains 21% oxygen and breathing 100% oxygen at high pressure results in substantially more oxygen uptake by the lungs.
Are there any side effects?
HBOT is a relatively safe procedure, however as with any treatment, HBOT carries some risk. A minor problem is that increased air pressure may create a temporary feeling of fullness in the ears, similar in sensation to what is felt in an aeroplane or at a high elevation. This is relieved by yawning or swallowing. Other potential risks include temporary vision changes such as near sightedness, due to short-term eye lens changes. Middle ear injuries may occur (eg leaking fluid, eardrum rupture) as a consequence of increased air pressure. A rare side effect is oxygen toxicity or poisoning, caused by too much oxygen in the central nervous system, which may cause lung problems or seizures.
How many HBOT sessions are required?
The number of HBOT sessions required depends on the medical condition being treated. It’s important to remember that in the setting of wound care, HBOT is usually a component of a comprehensive treatment plan, which may include other therapies and drugs.
Who decides HBOT is needed?
A person’s doctor or specialist determines when HBOT is required.
Further Reading
Mayo Clinic. Tests and procedures. Hyperbaric oxygen therapy.
http://www.mayoclinic.org/tests-procedures/hyperbaric-oxygen-therapy/basics/definition/prc-20019167
John Hopkins Medicine. Health library. Complications of hyperbaric oxygen therapy. http://www.hopkinsmedicine.org/healthlibrary/conditions/physical_medicine_and_rehabilitation/complications_of_hyperbaric_oxygen_treatment_134,148/
Booklet designed by staff at the Alfred Hospital (Melbourne, Australia) for patients undergoing HBOT.
https://www.alfredicu.org.au/assets/Documents/Services-Docs/Hyperbaric-Docs/Hyperbaric-Patient-Information-Wound-healing.pdf