Oxygen is essential for life. Hyperbaric
oxygen therapy, or HBOT, is a form of therapy that delivers 100%
oxygen to the body at high pressures. At higher pressures, oxygen
delivery to the tissues is enhanced. Continue reading to learn more
about hyperbaric oxygen therapy, benefits of treatment, and side
effects of use.
Oxygen therapy is the use of supplemental oxygen to treat a variety
of medical conditions. There are two main types of oxygen therapies
available:
Normobaric oxygen therapy is supplemental oxygen administered at the
same pressure of our atmosphere (1 atm). Depending on the medical
condition, 40 to 100% of saturated oxygen is delivered to the body.
As excessive oxygen can be harmful, normobaric oxygen therapy should
be regulated. In the absence of correct medical supervision,
normobaric oxygen therapy can also cause heart disease,
inflammation, diabetes, and aging.
Hyperbaric oxygen therapy is 100% saturated supplemental oxygen
delivered at higher atmospheric pressures. Patients are placed in a
high pressure, full body chamber (hyperbaric chamber). This
increases oxygen delivery to all of the tissues of the body.
Treatment schedules of hyperbaric oxygen therapy vary between 60 to
120 minutes, 1 or more times daily.
Hyperbaric oxygen therapy is approved for the treatment of a number
of conditions such as air or gas embolisms, burns, diabetic wounds,
and traumatic ischemia.
Mechanism of Hyperbaric Oxygen Therapy
Blood is made up of 4 components: Plasma, red blood cells, white
blood cells, and platelets. Oxygen is transported through red blood
cells that contain the protein hemoglobin. Hemoglobin is an
iron-containing protein that oxygen can bind to.
The only differences between normobaric and hyperbaric oxygen
therapy are the pressure that they’re applied at and the method of
delivery. Both forms of therapy increase the amount of oxygen that
is delivered in the blood.
With hyperbaric oxygen therapy, there is a 10 to 20 fold increase in
blood plasma oxygen. It also induces an increase in red blood cells.
Clinically, hyperbaric oxygen therapy promotes:
Cell growth
Reduction of swelling
New blood vessel formation
Tissue repair
Wound healing
Hyperbaric oxygen therapy causes the controlled release of reactive
oxygen species (ROS) in damaged and infected tissues.
The enhanced healing action of hyperbaric oxygen therapy is due to
its direct antifungal activity mediated by reversal of fungal growth
and restoration of protective immune response.
Health Benefits of Hyperbaric Oxygen Therapy
1) Hyperbaric Oxygen Therapy Can Treat Decompression Illness
Scuba diving with a compressed air supply can cause decompression
sickness and arterial gas embolism, a potentially lethal event.
Decompression sickness is caused by the formation of nitrogen
bubbles in the blood and tissues of scuba divers who surface too
quickly.
Arterial gas embolisms happen after decompression sickness. The gas
bubbles in the bloodstream and tissues travel within the blood and
block the supply of blood to the lungs (pulmonary vein).
According to the US Navy 6 treatment manual, hyperbaric oxygen
therapy is the preferred way to treat decompression sickness.
Hyperbaric oxygen therapy is most successful in treating
decompression illness within 24 hours of surfacing.
In a clinical case report, a single session of emergency hyperbaric
oxygen therapy removed the gas and air bubbles in the patient’s
blood vessels, hip, lower spine, brain sinuses, and joints.
Hyperbaric oxygen therapy also protected rats from spinal cord
injury during simulated diving.
In rabbits, hyperbaric oxygen therapy reduced lung injury caused by
decompression sickness.
2) Hyperbaric Oxygen Therapy Can Reverse Effects of Air Embolism
Air embolism is caused by the introduction of air bubbles into the
bloodstream those block arteries.
Air embolism is a rare but potentially fatal complication of
surgical procedures and causes serious damage to the brain, heart,
and lungs.
Clinical symptoms of air embolism depend on the location of the air
bubble in the body. Early treatment is critical for survival.
A clinical case study of a patient suffering from an air embolism
after open heart surgery showed complete recovery after 7 sessions
of hyperbaric oxygen therapy.
A clinical case study of an immunocompromised patient with air
embolism showed that emergency hyperbaric oxygen therapy cured brain
(ischemic) stroke symptoms caused by an invasive fungal infection.
3) Hyperbaric Oxygen Therapy Cures Carbon Monoxide and Cyanide
Poisoning
Carbon monoxide can displace oxygen in the blood. This reduces the
amount of oxygen supplied to tissues.
In a population-based study of 7,287 patients suffering from carbon
monoxide poisoning, hyperbaric oxygen therapy reduced the death rate
and improved patient lifespan. Therapy was more effective in younger
patients (<20) and patients with acute lung failure.
In rats with acute carbon monoxide poisoning, hyperbaric oxygen
therapy reduced brain damage and behavior abnormalities.
Adjunctive hyperbaric oxygen therapy also protected rats from oxygen
toxicity caused by cyanide poisoning.
4) Hyperbaric Oxygen Therapy Improves Vision Loss
Obstruction of eye blood vessels (central retinal artery and vein
occlusion and branch retinal artery occlusion) is a common cause of
blindness in elderly patients.
In order for therapy to be successful, hyperbaric oxygen therapy
should be prescribed in the first 24 hours after the onset of vision
loss.
In 2 elderly patients with acute blindness, 8 to 9 sessions of
hyperbaric oxygen therapy significantly improved sight.
In young people, certain genetic mutations (factor V Leiden
mutation, methylenetetrahydrofolate reductase mutation) can also
block the retinal artery and vein.
Supplemental hyperbaric oxygen therapy for 20 days prompted visual
recovery of a teenager with branch retinal artery occlusion caused
by a mutation in the protein methylenetetrahydrofolate reductase (MTHFR
gene).
In a patient with combined central retinal artery and vein
occlusions caused by factor V Leiden mutation, urgent administration
of 9 sessions of hyperbaric oxygen therapy improved vision.
In one rare case, exposure to high altitude can block the retinal
artery and cause vision loss. A patient suffering from visual loss
due to high altitude exposure regained her sight after treatment
with hyperbaric oxygen therapy for 11 days.
Along with increasing oxygen supply to the eye’s tissues, hyperbaric
oxygen therapy also reduces swelling of the retina [R, R, R].
5) Hyperbaric Oxygen Therapy Can Heal Tissue Infections
Bacterial infections can destroy (necrosis) soft tissues and, if
left untreated, can be life-threatening (Fournier gangrene, gas
gangrene, and necrotizing fasciitis).
A review of 1,583 patient reports found that supplemental hyperbaric
oxygen therapy cured severe cases of soft tissue bacterial
infections and increased survival.
In bacterial infections, hyperbaric oxygen therapy reduced swelling,
stimulated tissue growth, inhibited bacterial toxin production,
enhanced antibiotic efficiency, and protected against infections.
6) Hyperbaric Oxygen Therapy Reduces Chronic Pain
Hyperbaric oxygen therapy in 60 patients (RCT) with chronic pain
disorder (fibromyalgia) for 8 weeks improved brain and nerve
activity.
In a patient suffering from chronic muscle/bone disease (Complex
Regional Pain Syndrome), 3 weeks of hyperbaric oxygen therapy
reduced swelling, pain, and improved motion of the lower limbs.
As hyperbaric oxygen therapy decreases pain, it also reduces
dependence on painkillers in patients with chronic pain.
Cellular death of bone tissue (osteonecrosis) is most commonly
attributed to an interruption of blood supply. In multiple bone cell
studies (osteoblasts/osteoclasts), hyperbaric oxygen therapy
promoted the generation of bone mass and prevented bone loss.
7) Hyperbaric Oxygen Therapy Benefits Skin Ulcers
In 35 patients with treatment-resistant skin ulcers (vasculitis), a
4-week course of hyperbaric oxygen therapy improved recovery in 80%
of the patients.
Similarly, in a patient suffering from treatment-resistant skin
ulcers, 4 weeks of hyperbaric oxygen therapy promoted complete
recovery.
8) Hyperbaric Oxygen Therapy May Improve Brain Injuries and Trauma
In 60 patients with spinal injuries (RCT), hyperbaric oxygen therapy
for 8 weeks improved nerve function and reduced depression and
anxiety.
A meta-analysis of 8 studies of patients with traumatic brain
injuries showed that hyperbaric oxygen therapy significantly
improved survival rate.
A systematic review of 11 studies with 705 patients (RCT) determined
that hyperbaric oxygen therapy decreased disability and improve
brain activity.
In a 2-year-old girl suffering from a brain injury, 27 days of
hyperbaric oxygen therapy restored the loss of brain tissue and
resulted in complete recovery.
However, a meta-analysis of 571 patients with traumatic brain injury
showed that using hyperbaric oxygen therapy in addition to standard
treatments was not beneficial. Patients had improved survival
outcomes initially, but long-term symptoms remained in those who
were not treated immediately.
In multiple rat models of brain injury, hyperbaric oxygen therapy
reduced inflammation, inhibited nerve injury, increased the growth
of nerve cells and blood vessels, and reduced pain [R, R, R, R, R].
In rats, hyperbaric oxygen therapy protected the brain by decreasing
the production of inflammatory factors and improving the antioxidant
defense pathways.
In rat models, hyperbaric oxygen therapy induced the production of
heat shock proteins and cellular pathways that protect spinal
neurons against oxidative injury.
A study with immune cells from severely injured patients found that
a single session of hyperbaric oxygen therapy suppressed
inflammation.
9) Hyperbaric Oxygen Therapy Improves Diabetic Ulcers
Diabetic foot ulcers and chronic kidney diseases are common causes
of reduced blood flow in arteries.
In a clinical study, 146 patients treated with supplementary
hyperbaric oxygen therapy were found to recover from chronic
diabetic foot ulcers.
In 2 patients with chronic kidney disease, 20 sessions of hyperbaric
oxygen therapy (in addition to standard therapies) completely cured
ulcers.
A meta-analysis of 9 studies (RCTs) consisting of 526 patients
concluded that hyperbaric oxygen therapy is a beneficial therapy for
foot ulcers.
In a diabetic rat model, hyperbaric oxygen therapy for 6 weeks
reduced inflammation, increased blood flow, and improved wound
healing.
10) Hyperbaric Oxygen Therapy Can Improve Hearing Loss
The sensorineural hearing loss is a condition caused by loss of
nerves or cells within the ear. It accounts for about 90% of hearing
loss and deafness.
A review of clinical data from 167 patients showed that adjunctive
hyperbaric oxygen therapy is effective in treating patients with
sensorineural hearing loss.
In guinea pigs, hyperbaric oxygen therapy for 4 weeks upregulated
protective enzymes in the inner ear (cochlea).
11) Hyperbaric Oxygen Therapy May Benefit Anemia
When applied early, hyperbaric oxygen therapy has a positive effect
on severe anemia. It benefits patients who cannot accept blood
transfusion for religious reasons, immunologic reasons, or blood
availability problems.
In a patient suffering from hemorrhage, 10 sessions of hyperbaric
oxygen therapy were found to relieve symptoms.
12) Hyperbaric Oxygen Therapy Reduces Growth of Brain Abscess
In 40 patients with spontaneous brain abscess (RCT), hyperbaric
oxygen therapy administered in addition to antibiotics resulted in
the complete recovery for all patients.
In 5 children with brain abscesses, hyperbaric oxygen therapy helped
promote healing and survival.
Hyperbaric oxygen therapy is associated with fewer treatment
failures, a decrease in the need for reoperation, and an improved
long-term outcome of patients with spontaneous brain abscess.
13) Hyperbaric Oxygen Therapy Can Benefit Fungal InfectionS
Mucormycosis, a life-threatening invasive fungal infection, affects
people with a suppressed immune response.
A patient with a blood disorder (thalassemia) was found to be cured
of fungal wound infections after 40 sessions of hyperbaric oxygen
therapy.
Twenty sessions of hyperbaric oxygen therapy also cleared a fungal
infection in an elderly patient with diabetes and liver failure.
Hyperbaric oxygen therapy also increases the production of free
radicals, which helps to combat fungus.
However, long-term production of free radicals can result in
oxidative stress and cell damage.
14) Hyperbaric Oxygen Therapy Reduces Bone Infections
Osteomyelitis is the infection of bone or bone marrow and is usually
caused by bacteria.
A review of 181 patient case reports found that hyperbaric oxygen
therapy cured 82.6% of patients with recurrent chronic bone
infection.
In animal studies, hyperbaric oxygen therapy promoted bone
regeneration following injury and surgery.
15) Hyperbaric Oxygen Therapy Can Improve Recovery from Radiotherapy
Frequent use of radiation therapy on cancer cells results in
injuries of normal tissues surrounding the tumors.
A review of 14 studies with 753 participants (RCTs) concluded that
hyperbaric oxygen therapy reduced the radiation injury caused in the
head, neck, anus, and rectum.
In 57 breast cancer patients, 47 sessions of hyperbaric oxygen
therapy decreased tissue toxicity, pain, and oversensitivity of the
affected areas.
A breast cancer patient with skin ulcer that developed 25 years
after therapy completely recovered after 101 sessions of hyperbaric
oxygen therapy.
Radiation cystitis is a complication caused by the inflammation of
the bladder (cystitis) during radiotherapy of the hip region
(pelvic) in patients with urological cancers. In 12 patients with
radiation cystitis, hyperbaric oxygen therapy improved symptoms in
67% of the patients.
In 21 patients with radiation-induced damage to the upper jaw bone,
hyperbaric oxygen therapy cured majority of the patients (85.7%).
Similarly, 27 patients with radiation-induced damage of the lower
jaw bone benefited from supplementing their current treatments with
hyperbaric oxygen therapy.
In mice, hyperbaric oxygen therapy prevented radiation-induced
damage to the lower jaw bone. It also improved recovery of bone
volume and viability.
Hyperbaric oxygen therapy prevents the production of proteins that
cause fibrosis in mice with head and neck radiation exposure.
Fibrosis is a condition caused by the overgrowth of tissue and
scarring.
Supplementing hyperbaric oxygen therapy for radiation-induced damage
to the jaw bones should be considered for patients who are not
responsive to therapy.
16) Hyperbaric Oxygen Therapy Can Heal Burns
Hyperbaric oxygen therapy increases the supply of oxygen to the
areas suffering from burns.
Over 800 burn patients treated with hyperbaric oxygen therapy
exhibited longer lifespans and shorter recovery times than patients
who just used standard therapy.
The rate of infections (sepsis) was decreased in 57 burn patients
supplemented with hyperbaric oxygen therapy in addition to standard
treatment.
17) Hyperbaric Oxygen Therapy Increases Tissue Graft Acceptance
A tissue graft is a medical procedure in which damaged tissue is
replaced using donated healthy tissue. Failure of tissue grafts
resulted in tissue loss, additional surgery, increased treatment
costs, and unfavorable psychosocial patient effects.
Multiple animals (rats, rabbits, and guinea pigs) and human case
studies have shown the success of hyperbaric oxygen therapy in
rescuing skin grafts by increasing oxygen supply to the tissues,
improving fibroblast function and initiating the growth of new blood
vessels.
In mice, the addition of hyperbaric oxygen therapy inhibited the
immune response and increased the chances of graft acceptance during
transplantation.
18) Hyperbaric Oxygen Therapy Can Improve Symptoms of Stroke and
Heart Disease
In 73 post-stroke patients (RCT), 40 sessions of hyperbaric oxygen
therapy significantly decreased damage to the brain and nerves.
In 12 patients suffering from a stroke after heart surgery,
hyperbaric oxygen therapy caused a full recovery in 10 out of the 12
patients.
Multiple animal studies with rats have found that hyperbaric oxygen
therapy promoted growth and decreased inflammation of the brain
tissues. Additionally, it increased oxygen supply and improved
oxygen absorption.
In rats, adding hyperbaric oxygen therapy to standard therapies
suppressed inflammation of the heart tissues and protected against
bacterial infection of the inner lining of the heart (endocarditis).
Studies with rat models have found that HBOT protected heart
function via antioxidant activity.
19) Hyperbaric Oxygen Therapy Can Improve Dementia and Alzheimer’s
Disease
In an analysis of 64 patients taking donepezil (RCT), a drug that
treats Alzheimer’s, patients receiving additional hyperbaric oxygen
therapy for 12 weeks had significantly more cognitive improvements.
In a patient with post-operative dementia, 40 sessions of hyperbaric
oxygen therapy in addition to other therapies improved cognition and
reduced confusion. It also improved memory, social interaction,
sleep patterns, and physical independence.
In multiple rat models of Alzheimer’s disease, hyperbaric oxygen
reduced inflammation, and proteins linked to Alzheimer’s.
In a rat model of Alzheimer’s disease, hyperbaric oxygen therapy
improved cognitive ability and reduced brain damage.
20) Hyperbaric Oxygen Therapy May Reduce Cancer Growth
Many cell studies have shown that hyperbaric oxygen therapy is
beneficial in reducing tumor growth. Although oxygen therapy
promotes blood vessel growth in normal cells, hyperbaric oxygen
therapy reduces blood vessel formation around tumor cells. This
decreases the supply of oxygen to the cancerous tissue, promoting
death.
In mice injected with human breast cancer cells, hyperbaric oxygen
therapy reduced the spread of cancerous cells and suppressed tumor
growth.
21) Hyperbaric Oxygen Therapy May Treat Liver Injury
Animal studies with rats confirmed that hyperbaric oxygen therapy is
protective against liver injury. These effects were better in rats
who underwent therapy in the earlier stages of the disease.
In rats with liver injuries, hyperbaric oxygen therapy reduced
oxidative stress and increased cell recovery and growth.
22) Hyperbaric Oxygen Therapy Improves Frostbite
In a case study of 2 patients suffering from frostbite, 25 to 30
sessions of hyperbaric oxygen therapy preserved tissue health and
promoted recovery of the dead tissue.
Contraindications of Hyperbaric Oxygen Therapy
Before using supplemental oxygen therapy, patients must be inspected
for pneumothorax. Pneumothorax is caused by the buildup of air in
the space between the chest wall and the lungs. If the pneumothorax
is unrecognized or untreated, using oxygen therapy could result in
the lungs collapsing and ultimately death.
Oxygen constricts blood vessels, and hyperbaric oxygen therapy might
increase pressure on the heart. Patients with a history of
congestive heart failure are also at risk of adverse effects.
Highly concentrated oxygen can easily catch on fire. Therefore,
fires surrounding hyperbaric oxygen chambers, oxygen gas cylinders,
tanks, and concentrators are a high risk for danger.
Side Effects of Hyperbaric Oxygen Therapy
Normobaric is safer than hyperbaric oxygen therapy, although
hyperbaric oxygen therapy is more effective.
Despite the risks and side effects, proper use of hyperbaric oxygen
therapy is considered safe and low-risk interventions.
Due to the high pressure, hyperbaric oxygen therapy has more risks
than normobaric therapy. These include:
Retinopathy in premature babies: When the blood vessels connecting
to the eyes do not develop (retinal vessels)
Bronchopulmonary dysplasia in premature babies: Results in lung
dysfunction (respiratory distress syndrome). Oxygen therapy is
therefore not recommended for infants and children.
Inflammation of the lining of undeveloped lungs
Injured airways
Production of breathing difficulties and lung dysfunction
Can result in asthma-like symptoms and exercise intolerance
Production of oxidative stress that could potentially result in
seizures
Barotrauma to the ears and sinuses (mild)
Short-term short-sightedness (myopia)
Accelerated cataract growth in eyes
Hyperbaric oxygen therapy can also cause distress in patients
suffering from claustrophobia, high blood pressure, and low blood
glucose, and can cause heart failure.
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