Hyperbaric Oxygen Therapy

General information

Hyperbaric Oxygen Therapy (HBOT) is a method used to treat a variety of ailments. Hyperbaric Oxygen Therapy is defined as a treatment in which a patient breathes 100% oxygen intermittently under a pressure of greater than sea level or our atmosphere. This treatment can be carried out in one of two ways. Multiplace chambers are designed to hold 2 or more people. Monoplace chambers are single person chambers that are pressurized with oxygen. Dual or Both types may be pressurized with air while patients breathe oxygen via a 02 masks, hood system, or tube, for times that typically extend 45 minutes to 60 minutes during which the patient breathes 100% oxygen.

It is a method of administering pure oxygen at greater than atmospheric pressure to a patient in order to improve or correct conditions. By providing pure oxygen in a pressurized chamber we are able to deliver 10-15 times more oxygen then if delivered at sea level or at normal atmospheric levels. It has the capacity to promote the growth of new blood vessels, decreases swelling and inflammation deactivates toxins, increases the body's ability to fight infections, clears out toxins and metabolic waste products, and improve the rate of healing. It should be used to compliment conventional therapies and treatments.

Uses of HBOT

Throughout the world there are around 66 conditions treated routinely with HBOT. There are currently 13 conditions are treated by hyperbaric oxygen therapy which are reimbursed in U.S. They are:

• Air or gas embolism
• Carbon monoxide poisoning and CO poisoning complicated by cyanide poisoning.
• Clostridal myositis and myonecrosis, (gas gangrene)
• Crush injury, compartment syndrome, and other acute traumatic ischemias.
• Decompression sickness
• Enhancement of healing in selected problem wounds
• Exceptional blood loss (anemia)
• Intracranial abscess, actinomycosis
• Necrotizing soft tissue infections
• Refractory osteomyelitis (Infected bone)
• Delayed radiation injury (soft tissue and bony necrosis)
• Skin grafts and flaps (compromised)
• Thermal burns

Mechanism:

Increasing the partial pressure of oxygen is the main therapeutic value of hyperbaric oxygen therapy. When a patient breathes pure oxygen at 3 times atmospheric pressure, arterial oxygen pressures in excess of 2000 mmHb are possible. This is around 20 times higher than normal. This is bactericidal to clostridium perringens, stops toxin production in gas gangrene, and more rapidly displaces carbon monoxide from possible neurological damage.

The diffusion of oxygen increases two to three times under hyperbaric conditions in the hypoperfused wound. This restores tissue oxygen tensions back to appropriate levels. Processes that are essential for wound healing are oxygen dependent. Fibroblast proliferation, collagen production, neovascularization and enhanced WBC function results in a rich vascular bed for healing with or without skin grafting.

Amino glycoside effectiveness is promoted by increased oxygen tensions.

HBOT activates neutrophils to become "bactericidal maniacs". HBOT reduces reperfusion injury.

Mechanical effects

According to Boyle's Law any free gas trapped in the body will decrease in volume as pressure exerted on it increases. Reduction in bubble size may allow it to pass through the circulation, or at least travel into a smaller vessel, which will reduce the size of any resulting infarction. This effect is useful in the management of gas embolism and decompression sickness.

When the body is flooded with oxygen forces, there is rapid elimination of other gases which reduces the damage caused by toxic gases such as carbon monoxide. The elevated pressures is further accelerated to get more elimination. Hyperbaric oxygen which acts as an alpha-adrenergic drug can result in reduction of edema following burns or crush injuries.

During HBOT, it physically dissolves extra oxygen into the plasma. The quantity of oxygen carried and transferred to ischemic tissue by the blood is increased. Osteoclastic and osteoblastic activity, collagen matrix formation and the breakdown of many toxins can be promoted with relieving the ischemia with increased oxygenation. It also helps the ischemic tissue meet the increased metabolic need required by the healing processes.

During the treatment

During the treatment the patients receiving hyperbaric oxygen therapy will sit comfortably in the multi-place chamber, breathing 100% oxygen under increased atmospheric pressure. During the hour-long treatment, patients relax, watch television or movies, or even take a nap while the highly trained technicians carefully monitor them. They can communicate easily to individuals outside the chamber through a closed circuit TV and intercom system.

Side effects

As with any treatment, side effects are possible. However, with hyperbaric oxygen therapy they are minimal. The most common is barotrauma to the ears and sinuses caused by pressure changes.

Patients are taught auto inflationary techniques to promote adequate clearing of the ears during treatment. Decongestants may be helpful. This problem is temporary and resolves when hyperbaric oxygen therapy is completed.

If the patient has ear pain or is unable to clear his or her ears, the insertion of myringotomy tubes may be necessary before the treatment continues.

Other side effects are rarer

• Oxygen toxicity can cause CNS and pulmonary effects. Seizures occur rarely during treatment and are self limiting.
• Seizures will cease when the patient is removed from breathing the pure oxygen.
• Factors such as history of seizures, high temperature, acidosis and low blood sugar are taken into Account before treatment is begun.
• Pulmonary oxygen toxicity may occur in patients who require supplemental oxygen between 1 treatments. This is very rarely seen.
•  Some patients may suffer claustrophobia. This is managed by maintaining communication, use of relaxation techniques and mild sedation, if necessary. Incidents of claustrophobia, however, are decreased by large diameter Multiplace chamber.
•  Rarely, patients develop temporary changes in eyesight; these are minor and occur only in those individuals who have large numbers of treatments.
•  Vision usually returns to normal within eight weeks following the end of treatments.
  Patients with cataracts may experience accelerated maturation of the cataract, but the treatments do not cause cataract formation.
  
  Contraindications
  
  Any patient with any of the following conditions may not be a suitable candidate for HBOT: 
• Asthma
• Congenital spherocytosis
• Emphysema with CO2 retention
• Optic Neuritis
• Pneumothorax
• Pregnancy
• High Fevers
• History of middle ear surgery or disorders
• History of seizures
• Upper Respiratory Tract Infections
• Viral Infections
• Use of Cisplatinum / Disulphiram / Doxorubicin

For so many years, it was thought of HBOT only as a treatment for decompression sickness, however, the use of HBOT is becoming increasingly common in general practice as more doctors become acquainted with new applications. Doctors now realize that HBOT has other uses, including the treatment of non-healing wounds, Carbon Monoxide poisoning, various infections, damage caused by radiation treatments, near- drowning, near-hanging, brain and nerve disorders, cardiovascular disorders; and some digestive system disorders.

There are approximately 66 applications that have been noted to receive benefit from HBOT, including:

• Stroke
• Traumatic Brain Injury
• Cerebral Palsy
• Autism
• Multiple Sclerosis
• Chronic Fatigue Syndrome & Fibromyalgia
• Wound Healing
• Diabetes
• Sports Injuries
• Cosmetic and Periodontal Surgery

Cerebral palsy is thought in some cases to be caused by a lack of oxygen to the developing brain. For this reason people have become interested in the possible use of hyperbaric oxygen therapy to 'treat' children with cerebral palsy.

Traditionally, scientists and physicians thought that neurological tissue damage would result in cell death within approximately four to six hours of injury. But Dr. R. Neubauer thinks other way. According to Dr. R. Neubauer these brain cells (neurons) receive enough oxygen to stay alive but not to perform brain functions. He suggests that neurons can remain in 'idling condition' for many years after an injury.

Hyperbaric Oxygen Therapy may, in this view, promote the restoration of full neurological functioning to neurons in this state.

SPECT SCAN imaging (an advance technique that assesses brain function) has been used to demonstrate that exposure to Hyperbaric Oxygen Therapy following brain injury is associated with increased brain activity. It has been postulated that these apparent positive effects may also be possible in treating cerebral palsy. It is important to note here that Hyperbaric Oxygen Therapy and SPECT scans are relatively new techniques, and the meaning of these findings on the normal brain is uncertain. At the same time it is not clear whether a change in a SPECT SCAN has any relationship to improved function of the brain or of the person.

Studies show that the effectiveness of hyperbaric oxygen therapy in children with cerebral palsy is linked to its enhancing the function of previously damaged neurons (brain/nerve cells). These neurons have been called "idling neurons" in that while they are still alive, they have been damaged to the extent that their function is compromised. Hyperbaric oxygen facilitates the restoration of these damaged neurons which improves brain function and the nervous system. The use of hyperbaric oxygen to help children with cerebral palsy is becoming more widespread in the world.

In children with cerebral palsy, Hyperbaric Oxygen therapy is administered at 1.5 ATA. Some research has been completed using treatment depths up to 1.75 ATA. Each treatment lasts one hour and one or two treatments are prescribed each day, five or six days per week. The total number of treatments given in each case varies. It is common to administer 40 treatments in the first phase of treatment. The question of further Hyperbaric Oxygen therapy is then resolved by the medical team involved in each case and is dependent upon a number of factors. However, many believe that if improvement is observed in the first phase of treatment, and then a break of one to three months should be taken, followed by another 20 Hyperbaric Oxygen therapy.

Dormant Areas

Cerebral palsy is a condition in which certain nerve cells in the brain may be permanently destroyed. It is important to note that although some of the brain may be permanently damaged when Traumatic brain injury occurs, a much larger area surrounding the permanently damaged area may also be affected. This larger area may be in a dormant state because the amount of oxygen it receives has been reduced due to a decrease in blood flow. Swelling and a change in cell physiology can cause reduced blood flow. Reduced blood flow-and the resulting decrease in oxygen levels at the cellular level-as well as the swelling of brain tissue are of particular importance in cerebral palsy in children. It is believed that the lack of oxygen and swelling of brain tissue plays a part in the inability of the myelin sheaths to develop. Myelin sheaths are coverings that protect nerve fibers in the brain. These nerve fibers connect the brain to the spinal cord and they play an important role in impulse transmission. The process of myelination-that is, the action of the delicate myelin sheath cells as they envelop the brain's nerve fibers-begins a month prior to birth and continues until about two years of age. If myelination does not properly occur, the nerve fibers are left exposed and they slowly deteriorate. This disrupts communication between the controlling nerve cells in the brain and the muscles. The result may be spasticity.

It is believed that the high oxygen levels that are attained in the body's cells during Hyperbaric Oxygen therapy cause a physiological change to the cells of this dormant area-effectively waking them up-thus, increasing the capacity for recovery. It is also believed that Hyperbaric Oxygen therapy reduces swelling in the brain by constricting blood vessels, and provides an ideal internal environment for the growth of new brain tissue.

Timing has a great role.

As earlier the hyperbaric Oxygen therapy is done, the better the opportunity for recovery. As far as there is the presence of idling cells in the brain, there is possibility of improvement. Generally it is considered that the idling cells can survive for 3-6 years, so maximum age for the treatment should be around 6 years.

Conclusion

Although there are a few studies which show positive effects of hyperbaric oxygen therapy in children with cerebral palsy but there is no study available which confirms the results. In some children when the pre -HBOT and post-HBOT SPECT SCANS were compared, a few changes were seen in the SPECT SCANS but how these were related to the functions, it could not be concluded. Before making hyperbaric oxygen therapy a standard treatment we need to study the effects.