Hyperbaric medicine is medical treatment in which an ambient pressure greater than sea level atmospheric pressure is a necessary component. The treatment comprises hyperbaric oxygen therapy (HBOT), the medical use of oxygen at an ambient pressure higher than atmospheric pressure, and therapeutic recompression for decompression illness, intended to reduce the injurious effects of systemic gas bubbles by physically reducing their size and providing improved conditions for elimination of bubbles and excess dissolved gas.
The equipment required for hyperbaric oxygen treatment consists of a pressure chamber, which may be of rigid or flexible construction, and a means of delivering 100% oxygen. Operation is performed to a predetermined schedule by trained personnel who monitor the patient and may adjust the schedule as required. HBOT found early use in the treatment of decompression sickness, and has also shown great effectiveness in treating conditions such as gas gangrene and carbon monoxide poisoning. More recent research has examined the possibility that it may also have value for other conditions such as cerebral palsy and multiple sclerosis, but no significant evidence has been found.
Therapeutic recompression is usually also provided in a hyperbaric chamber. It is the definitive treatment for decompression sickness and may also be used to treat arterial gas embolism caused by pulmonary barotrauma of ascent. In emergencies divers may sometimes be treated by in-water recompression (when a chamber is not available) if suitable diving equipment (to reasonably secure the airway) is available.
A number of hyperbaric treatment schedules have been published over the years for both therapeutic recompression and hyperbaric oxygen therapy for other conditions.
Scope
Hyperbaric medicine includes hyperbaric oxygen treatment, which is the medical use of oxygen at greater than atmospheric pressure to increase the availability of oxygen in the body; and therapeutic recompression, which involves increasing the ambient pressure on a person, usually a diver, to treat decompression sickness or an air embolism by eliminating bubbles that have formed within the body.
Medical uses
In the United States the Undersea and Hyperbaric Medical Society, known as UHMS, lists approvals for reimbursement for certain diagnoses in hospitals and clinics. The following indications are approved (for reimbursement) uses of hyperbaric oxygen therapy as defined by the UHMS Hyperbaric Oxygen Therapy Committee: Air or gas embolism; Carbon monoxide poisoning; Carbon monoxide poisoning complicated by cyanide poisoning; Central retinal artery occlusion; Clostridal myositis and myonecrosis (gas gangrene); Crush injury, compartment syndrome, and other acute traumatic ischemias; Decompression sickness; Enhancement of healing in selected problem wounds;. Diabetically derived illness, such as short-term relief of diabetic foot, diabetic retinopathy, diabetic nephropathy; Exceptional blood loss (anemia); Idiopathic sudden sensorineural hearing loss; Intracranial abscess; Mucormycosis, especially rhinocerebral disease in the setting of diabetes mellitus; Necrotizing soft tissue infections (necrotizing fasciitis); Osteomyelitis (refractory); Delayed radiation injury (soft tissue and bony necrosis); Skin grafts and flaps (compromised); Thermal burns.
There is no reliable evidence to support its use in autism, cancer, diabetes, HIV/AIDS, Alzheimer's disease, asthma, Bell's palsy, cerebral palsy, depression, heart disease, migraines, multiple sclerosis, Parkinson's disease, spinal cord injury, sports injuries, or stroke. Furthermore, there is evidence that potential side effects of hyperbaric medicine pose an unjustified risk in such cases. A Cochrane review published in 2016 has raised questions about the ethical basis for future clinical trials of hyperbaric oxygen therapy, in view of the increased risk of damage to the eardrum in children with autism spectrum disorders. Despite the lack of evidence, in 2015, the number of people utilizing this therapy has continued to rise.
There is also insufficient evidence to support its use in acute traumatic or surgical wounds.
Hearing issues
There is limited evidence that hyperbaric oxygen therapy improves hearing in patients with sudden sensorineural hearing loss who present within two weeks of hearing loss. There is some indication that HBOT might improve tinnitus presenting in the same time frame.