Hyperbaric oxygen therapy

What is Hyperbaric Oxygen therapy?

Hyperbaric oxygen therapy (HBOT) is a treatment that employs the use of saturated oxygen at an elevated atmospheric pressure to enhance the natural healing process. At pressure twice or thrice the normal atmospheric pressure, HBOT is a reimbursed treatment for several conditions. It is proposed that the delivery of hyperbaric (high-pressure) pure oxygen not only boosts the body’s ability to recuperate quickly but also stimulates the cellular defences to actively fight infectious agents.

It is a well-established treatment modality for decompression sickness, that is a potential risk of scuba diving. HBOT is carried out in a hyperbaric oxygen chamber that can either be a Monoplace, i.e. can facilitate a single patient or a Multiplace, i.e. house two or more patients at the same time. Depending on the pathology, tolerability of the treatment, and the treatment responses, HBOT duration and frequency can vary from a few sessions to multiple sessions daily or weekly, for usually a period over 4-6 weeks. As this is a non-invasive treatment modality, it is a relatively painless and safe alternative to multiple invasive procedures that carry a high complication risk.

How does Hyperbaric Oxygen therapy work?

Under normal conditions, the majority of the oxygen inhaled enters the bloodstreams and binds to a protein called the haemoglobin. Only a small percentage of this oxygen dissolves in the blood itself. Under hypoxic conditions that are situations where blood cannot deliver adequate oxygen to tissues, such as brain injuries, the need for a measure which increases oxygenation of the blood is essentially therapeutic. HBOT comes handy in such a situation as it readily exposes the blood to high-pressure oxygen that readily dissolves in blood and improves cellular functions.

Similarly, for the natural process of wound healing to occur, a higher level of oxygen is required to fuel the increased metabolic demands. It is estimated that increasing the atmospheric pressure to 0.5-1.5 times can raise the oxygen levels in blood up to 700% to 1200%. At this concentration oxygen acts as a drug itself, accelerating the process of healing by stimulating the mitochondria, that are the energy stores of the cell. 

Figure A shows the circulatory system (red), lymphatic system (green), and brain and spinal
cord (orange) under normal conditions.
O2 is transported only by red blood cells. 

Figure B shows the body under hyperbaric conditions. All body fluids carry O2 and saturate the body with oxygen.

What are the indications of Hyperbaric Oxygen therapy?

The use of hyperbaric oxygen therapy has been frequently employed to treat the following conditions:

1. Carbon monoxide poisoning

2. Cyanide poisoning

3.  Severe anaemia

4.  Crush injuries

5.  Burns

6.  Brain abscess

7.  Traumatic brain injury

8.  Osteomyelitis

9.  Delayed radiation injury

10.  Frostbite

11.  Skin grafts and flaps at risk of tissue death

12.  Decompression sickness: seen in scuba divers that surface too quickly

13.  Gas gangrene; a form of gangrene in which gas collects in tissues

14.  Necrotizing fasciitis: flesh-eating bacterial soft tissue infections

15.  Air embolism: air bubble entrapment in blood vessels

16.  Non Healing diabetic wounds: such as diabetic foot ulcers.

What are the benefits of Hyperbaric Oxygen therapy?

The benefits of hyperbaric oxygen therapy can be appreciated due to the following reasons:

HBOT prevents cell death:

Any trauma or insult that damages the walls of the blood vessels leads to leakage of blood in tissue spaces resulting in swelling. Together these two deprive the cells of oxygenation, and the tissue starves to death. Introducing hyperbaric oxygen in this situation not only improves the oxygenation of tissue but also reduces the swelling thus preventing cell death. Hyperoxygentaion is also found to increase the rate of wound closure up to 70% in cases of chronic wounds.

HBOT reduces the risk of infections:

HBOT can essentially decrease the risks of infection by detoxifying the body of harmful toxins produced by infectious agents. Alongside, as it also increases the oxygen concentration in the tissues, it helps them resist infection. Lastly, it strengthens the activity of leukocytes, that are the white blood cells to fight any developing infections or free radicals.  

HBOT encourages tissue growth:

HBOT stimulates angiogenesis that is the formation of new blood vessels by encouraging the release of growth factors from existing cells. It also enhances the production of collagen that is essential for strengthening newly formed skin and blood vessels. HBOT is also found associated with recruiting the stem cells, which are special cells that have the potential to divide and replicate.

What are the potential side effects and complications associated with Hyperbaric Oxygen therapy?

Hyperbaric oxygen therapy is generally a safe procedure if protocols are properly followed. Complications and side effects are rare and may include:

1. Injuries to sinuses and middle ear including fluid leak and eardrum rupture, due to changes in air pressure.

2. Temporary nearsightedness (myopia): caused by a temporary change in eye lens position.

3. Lung collapse: may occur due to the air pressure changes (barotrauma) or excessive fluid buildup in the lungs (pulmonary edema) can be found.

4. Seizures: secondary to oxygen toxicity of the central nervous system. As prevention, short breaks are often regularly taken in between each session.

5. Lowered blood sugar: in people who have diabetes managed with insulin

6. In certain circumstances, the chamber is at risk of catching fire due to the oxygen-rich environment.

7. Some patients may experience claustrophobia or anxiety to sit or lay in a confined high-pressure chamber.

HBOT should, therefore, be avoided if the patient has an active or recent history of ear infections, ear surgery, fever, cold or lung pathologies.