One of the greatest risks in scuba diving is that of getting decompression sickness (DCS), often referred to as the bends, or arterial gas embolism (AGE). These are both conditions that together are termed decompression illness and they occur when the diver ascends more quickly than the nitrogen can be released into the blood stream and exhaled by the lungs. When this happens there are gas bubbles that reside in the body, in the tissues in DCS and in the lung circulation and blood in AGE, and these can cause a number of nasty symptoms that range in severity from simple joint pain and mottling of the skin to full neurological damage.
Hyperbaric oxygenation is also termed hyperbaric oxygen therapy and this is a treatment that is used to treat decompression illness, both DCS and AGE. This is a treatment in which the diver with decompression illness is administered 100% oxygen and is submitted to high pressures for a period of time to allow the nitrogen bubbles to be expelled from the body. This is generally done in what is termed a hyperbaric chamber or recompression chamber.
A hyperbaric chamber is a vessel that is large enough for a person to be inside. A person can enter and exit through an individually pressurized airlock and inside the main chamber the pressure is increased with the use of an air compressor. This allows the chamber to mimic the water pressure from the dive. The diver is put in the chamber and 100% oxygen is delivered while he or she sits in the high pressure chamber and can communicate with those outside the chamber via an intercom. Treatment in a hyperbaric chamber usually starts with oxygenation and pressures equivalent to 19 m (60 feet) of water depth.
So what exactly does the oxygen do when the person is in the hyperbaric chamber? It is important to make sure it is understood that the oxygen is not given because the diver is suffering from low oxygen levels. Oxygen is actually used on a daily basis by hospitals to treat people who have low oxygen levels, but in the case of DCS or AGE this oxygen is administered to help rid the body of the nitrogen gas bubbles that have formed.
When a diver is suffering from decompression illness, whether it is DCS or AGE, it is important that they receive treatment right away. An assessment of the diver at the dive site is necessary and First Aid treatment with oxygen is called for immediately. The diver should be classified as an emergency case (symptoms showing up within an hour of resurfacing), urgent (severe pain that has progressed slowly or not changed since surfacing), or timely (symptoms are not obvious or progress slowly over several days). Once the diver has been given First Aid treatment, he or she should be taken to the nearest medical facility in order to be stabilized before being transported to the nearest hyperbaric chamber. Once the patient is stabilized a call should be place to the Divers Alert Network (DAN), who will be able to give the location of the nearest hyperbaric chamber.
It is crucial to note that once oxygen is administered to the patient, the symptoms of decompression illness may disappear. However, this does not mean it is gone. If left untreated by recompression, then the symptoms may very well come back and serious injury can result. Treatment with recompression must be sought as quickly as possible as early on damage is generally reversible. If treatment has not been had within 24 hours after the accident, the damage may be permanent and the treatment may not work. However it is important to consult with a dive medicine specialist to be sure of the best course of action.
Once a diver has been treated for decompression illness, there may be residual pain around the area of the body that was affected. If there were neurological effects, these may persist after treatment is complete, but usually goes away after time, occasionally requiring physiotherapy and follow-up treatments. Fortunately, in most cases the patient will receive full recovery from all symptoms as long as treatment was started soon after the accident. When it comes to diving after being treated for decompression illness, if it was mild, with pain, but without neurological symptoms, divers can generally return to diving two to seven days after treatment. If there are neurological symptoms, then the diver must wait two to four weeks. If there were severe neurological symptoms, then the diver will have to be evaluated at three months after treatment and be given permission to dive from a dive medicine specialist. One way or another, the majority of those who do suffer from decompression illness will be able to dive again and that is great news.