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.
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:
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.