Hyperbaric oxygen therapy (HBOT) refers to the medical use of oxygen at a higher pressure and concentration than the standard atmospheric pressure of oxygen. This higher pressure of oxygen provides several therapeutic benefits to treat a wide range of conditions.
How Does Hyperbaric Oxygen Therapy Work?
HBOT often takes place in a hyperbaric chamber, which is an enclosed chamber or room that one patient (referred to as monoplace) or multiple patients (multi-place) can sit or lay down in. The chamber contains 100% oxygen at a pressure generally two to three times higher than normal atmospheric pressure, allowing for greater oxygen uptake by the blood and body tissues. There are three mechanisms by which the increased oxygen provided by HBOT works to treat conditions:
- Reducing formation of air bubbles and increasing gas return into solution. The increase in oxygen pressure aids in dissolving large air bubbles into the blood, helping to relieve dangerous acute conditions such as nitrogen bubbles in the blood or air embolisms.
- Favorable gas gradients between lungs/blood/tissue. The 100% concentration oxygen provided by the high-pressure chamber helps to increase oxygen diffusion from the lungs into the blood and from blood into tissues and clear other unwanted gasses at a faster rate (ex. carbon dioxide, carbon monoxide, nitrogen). This is useful in clearing poisonous gasses and lessening the effects of decompression sickness.
- Increasing oxygen-carrying capacity. Oxygen saturation of blood plasma increases since the increased pressure of inhaled air causes more oxygen to dissolve into fluid and be exchanged. This aids in improving gas exchange and healing of hypoxic tissues due to conditions such as ischemia, anemia, and necrosis.
The number of HBOT sessions a patient requires will vary depending on the condition being treated. Acute conditions such as carbon monoxide poisoning or decompression sickness may only require a few sessions, while chronic conditions such as poorly healing diabetic ulcers may require up to 40 sessions.
What Conditions Can Hyperbaric Oxygen Therapy Treat?
The FDA has approved HBOT’s use in the treatment of the following conditions:
- Decompression sickness
- Air/gas embolism
- Carbon monoxide poisoning
- Crush injury
- Severe anemia
- Delayed wound healing, especially in diabetic patients
- Brain abscess
- Bone or skin infection resulting in tissue death
- Radiation injury
- Poorly healing wounds/skin grafts/flaps
- Compartment syndrome
- Burns
- Necrotizing fasciitis
- Gas gangrene
- Sudden sensorineural hearing loss or vision loss
Risks and Contraindications of HBOT
HBOT is absolutely contraindicated in patients with untreated pneumothorax, and may worsen patients with inner ear barotrauma. Middle ear barotrauma and lung collapse/pneumothorax are potential risks of HBOT. Oxygen toxicity is another risk, which may lead to seizures. This can be mitigated by ensuring patients leave the chamber to take regular breaks to breathe normal air during their treatment. Patients with diabetes on insulin may experience lowered blood sugar as a result of HBOT. Finally, safety precautions must be taken to prevent risk of fire/combustion due to the increased ambient oxygen. The clinicians overseeing the hyperbaric oxygen therapy must ensure that the patient does not take/wear any flammable or combustible items with them when entering the chamber, such as lighters, batteries, and petroleum-containing products.
Sources
Hyperbaric Physics – StatPearls – NCBI Bookshelf (nih.gov)
