Drowning is the leading cause of injury-related deaths among U.S. children. Every year, an estimated 5,000 youngsters age 14 and under are hospitalized due to unintentional drowning-related incidents.
Fifteen percent die in the hospital, and as many as 20 percent suffer severe, permanent, neurological disability, according to the National Safety Council.
Typically, near-drowning victims undergo traditional medical treatments. But there is a promising treatment that’s less well-known among aquatics professionals and doctors: hyperbaric oxygen therapy.
Commonly called HBOT, this comfortable, noninvasive treatment uses 100 percent medical grade oxygen at increased atmospheric pressure to enhance oxygen delivery to areas of the central nervous system with poor or compromised circulation. The treatments are delivered inside a pressurized chamber. HBOT is not a new therapy. It has been widely accepted for treatment of scuba diving injuries for more than 100 years.
The physiology of HBOT is explained by chemistry gas laws. The laws of Boyle, Charles, Henry and Guy-Lussac illustrate how increasing the concentration of inhaled oxygen and increasing the ambient pressure will cause gas to dissolve into body fluids and tissue in direct proportion to the change in concentration and pressure. The air we breathe contains 21 percent oxygen. A monoplace chamber uses 100 percent oxygen. The hyperbaric chamber is used to increase the ambient pressure oxygen resulting in overall increased body tissue concentrations.
In drowning survivors, prolonged submersion results in tissue hypoxemia and acidosis. The degree of hypoxemia and acidosis determine the amount of damage to the central nervous system. Hypoxemia causes microcirculatory disturbances, including swelling and ionic changes in the blood vessels; red blood cells clump and are unable to pass through capillaries. This creates areas in the brain where neurons have compromised blood flow and diminished oxygen delivery. Though the neurons are viable, they are not functioning properly due to diminished oxygen delivery. These areas are referred to as the ischemic penumbra. The penumbra is the area of focus for hyperbaric oxygen treatment.
In a hyperbaric environment, oxygen delivery is enhanced and carried through the plasma to viable, nonfiring neurons in the penumbra. It is theorized that decreased brain swelling, new capillary growth and improvements in metabolism facilitated by oxygen result in clinically observed improvement in the patient treated with HBOT.
Many facilities throughout the United States are treating children with chronic anoxic brain injuries. When choosing a facility for treatment, it’s important to find a site with a physician trained in hyperbaric medicine through a course approved by the Undersea Hyperbaric Medical Society. The staff should be certified to operate hyperbaric chambers through the National Board of Diving and Hyperbaric Medical Technology, and have documented clinical experience with HBOT and neurological indications. The chambers should be certified and stamped by the American Society of Mechanical Engineers/ Pressure Vessels for Human Occupancy.
Hyperbaric oxygen is considered a therapy, not a cure, for anoxic brain injury. It should be seen and utilized as an additional therapeutic modality for brain injury patients already receiving traditional therapies such as physical, occupational, speech and the like. The most obvious improvements are seen in patients with hypotonia, hypertonia, cognitive deficits and impaired vision.
This therapy can be helpful, but it is not for everyone. There are known risks and side effects associated with hyperbaric oxygen. Most are similar to the potential side effects of recreational scuba diving, including barotrauma affecting the eardrum, sinuses or lungs. An overdose of oxygen for a prolonged period of time can result in oxygen toxicity, which manifests as seizures.
Due to the pressurized pure oxygen environment, the chamber is susceptible to fire hazard if the proper precautions and training are not taken by the facility administering the therapy.
Currently, the FDA has 14 approved indications for HBOT. These include scuba injuries such as “the bends,” diabetic foot ulcers and carbon monoxide poisoning. Anoxic brain injury, including drowning injuries at this time, is considered an “off-label” indication for HBOT.
Major medical insurance frequently covers treatments based on whether a therapy has obtained FDA approval. Generally, HBOT for treatment of anoxic brain injury is not covered by standard medical insurance.