Hyperbaric Oxygen Europe Guide

WHAT IS HYPERBARIC OXYGEN USED FOR?

Hyperbaric Oxygen (HBO) is used in a number of medical emergencies, where the patient might also need intensive care:

Air or gas embolism. This is where gas bubbles travel in the blood stream, and may block blood flow in organs like the brain and spinal cord, or the heart. The bubbles may get into the blood from the lungs when under pressure (like when diving), or else at the time of a surgical operation or trauma. HBO acts in several ways when this happens.
The extra pressure throughout the body physically makes bubbles smaller, so that they cause less blockage to blood flow.
Pure oxygen (which contains no nitrogen), allows the bubbles to get smaller by forcing the nitrogen out of the air in the bubbles.
The extra oxygen reaches tissues struggling beyond partially blocked blood vessels.
The extra oxygen helps to reduce swelling in the damaged tissues.
In this condition, HBO must be given as quickly as possible to limit the damage to the tissues; and emergency transport to a safe and appropriate HBO facility must be organised.

Decompression illness (‘The Bends’). This is where bubbles of nitrogen form in tissues where it has been dissolved under pressure (like breathing compressed air when diving); but then when the pressure is removed (decompression) the nitrogen is no longer dissolved, and cannot get out of the tissue fast enough to be breathed out. Bubbles can form in all tissues of the body, but especially where a lot of nitrogen can be dissolved under pressure (in or through fat), and where the blood drainage through veins is slow and inefficient (like the brain and the spinal cord).
HBO acts in several ways when this happens:

The extra pressure throughout the body physically makes bubbles smaller, so that they cause less physical damage in the tissues.
Pure oxygen (which contains no nitrogen), allows the bubbles to get smaller by forcing the nitrogen out of the bubbles.
The extra oxygen reaches tissues in the damaged area, allowing them to recover.
The extra oxygen helps to reduce swelling in the damaged tissues.
In this condition, HBOT should be given as soon as is safely possible. Like in air embolism, emergency transport may be necessary to take the patient to an appropriate HBO facility.

Carbon monoxide poisoning. Carbon monoxide (CO) can be breathed in from anything that is burning, such as a fire, a central heating system, or car exhaust. It does not matter what is burning (coal, oil, petroleum, wood, furniture) as long as it has carbon in it: and almost everything does. CO can also get into the body by breathing the fumes from paint-stripper. CO damages any tissue which normally uses oxygen, by blocking the delivery of oxygen to the cells as well as blocking its use inside the cells.

HBO is only indicated in severe cases of poisoning. Oxygen at normal atmospheric pressure should be given by face-mask as soon as possible to any patient with this condition; and HBOT is reserved for patients who have been unconscious, or who have neurological symptoms or signs, or who are pregnant, or who have any other evidence of a severe exposure.

HBO acts in several different ways in this condition:
The extra oxygen helps to remove CO from the cells and from the blood, so that it can be breathed out or destroyed in the body.
The extra oxygen reaches cells trying to repair the damage caused by the CO.
The extra pressure reduces swelling in the damaged tissues.
The main aim of HBOT in CO poisoning is to prevent long-term effects of the CO, such as memory problems and difficulties with balance and coordination. It may also help the patient to recover more quickly than with normal atmospheric oxygen therapy. There is evidence that it may also save life in some cases.

Clostridial myonecrosis (‘gas gangrene’). This is an infection by a bacterium called clostridium perfringens, which grows and spreads most rapidly in a low-oxygen containing environment. There are usually other bacteria with it. Tissues poorly supplied with blood, for instance where blood vessels are blocked or damaged, are most prone to this infection. The bacteria kill normal cells in the area of infection, and tend to spread rapidly. In the process, they release gas into the tissues, which can be felt by hand and seen on X-rays. They also release poisonous chemicals (including ‘alpha-toxin’) into the rest of the body; this can damage organs like the heart and kidneys, and cause death.

HBO at three atmospheres pressure sHyperbaric Oxygens the bacteria from spreading locally, and reduces the amount of alpha-toxin being produced. This gives more time for antibiotics to work, and for the infected tissues to be removed by surgery.

The mortality from this infection can be reduced by the early use of HBO; and if the patient survives, HBO can reduce the amount of tissue which has to be removed.
Other aggressive infections. There are a number of other infections of skin and muscle which can spread rapidly and damage the organs of the body. Examples are Fournier’s Gangrene and Necrotizing Fasciitis. In these infections, the bacteria are usually mixed; but they can mainly survive well in oxygen. So, these infections can develop in previously normal skin and muscle.

HBO improves the body’s own defence systems, because the white cells (which attack bacteria) need extra oxygen to work properly. This gives more time for antibiotics to work, and for the infected tissues to be removed by surgery. The mortality from this infection can be reduced by the early use of HBO; and if the patient survives, HBO can reduce the amount of tissue which has to be removed.

Crush injury. When a hand or foot, or a whole limb, are crushed, the damaged tissues may swell rapidly. This may compress the blood vessels running through the damaged area. So, the tissues beyond the crushed area may have a poor oxygen supply, which may lead to infections and other complications. In the damaged area itself, the swelling sHyperbaric Oxygens oxygen from reaching tissues which need to be repaired; and so, it becomes difficult to lay down new connective (‘scar’) tissue. After this, other complications may develop, which can affect the other organs of the body. It is common for amputation to become necessary.

HBO works in different ways, but can never substitute for surgical removal of tissues damaged beyond repair. The extra oxygen reduces swelling, by slowing the leak of fluid out of the damaged blood vessels. It also reaches tissues in the damaged area, allowing them to recover. The extent of tissue removal, and the need for amputation, are therefore reduced. In order to work, however, HBO must be used as early as possible.

Burns. When soft tissues (such as skin and muscle) are damaged by burning, the blood flow in the damaged area is sharply reduced. This causes an area of swelling which radiates away from the area of damage, in all directions. The swelling may extend deep into muscles, and over the surrounding skin, and cause more damage than the initial injury.

HBO can help to reduce this swelling. The extra oxygen slows down the leak of fluid out of the damaged blood vessels. It also reaches tissues in the damaged area, allowing them to recover. The extent of tissue removal, and the need for amputation, are therefore reduced. In order to work, however, HBO must be used as early as possible.

Sudden deafness. There is evidence that the prompt use of HBO in patients who have lost their hearing suddenly, may reduce the duration and extent of hearing loss. This is the subject of current research.

Severe haemorrhagic anaemia. In those patients who suffer serious blood loss, and who are unable for any reason to receive blood transfusion, the prompt use of HBO may help with short-term survival. Such patients commonly require intensive care at the same time. There is evidence that HBO may accelerate the production of a hormone called erythropoietin, which promotes the production of new red blood cells and haemoglobin, to replace what has been lost.

Near-hanging. There is some evidence that the extent of brain damage after near-hanging can be reduced by the prompt use of HBO.
There are a number of other conditions where HBO is used, where there is more time for planning, and where courses of treatment tend to be longer than for emergency referrals.

Ischemic skin flaps and grafts. Oxygen treatment is not usually applied where a skin graft is growing well; even if it is infected, HBO would not be a first-line treatment. However, if the graft is based on host tissue which is poorly supplied with blood, and there is evidence that the graft is not fully successful, then HBO can be used.

HBO helps to reduce congestion in the blood vessels of the graft, such as when the veins in the graft are not working properly.
HBO also helps with the circulation of blood through the graft, by making the red blood cells better able to move through the narrowest capillaries, and making the blood platelets less likely to clump together and block the flow.
In the longer term, HBO helps to develop new blood vessels through the graft, which maintains the benefit of the earlier treatments. By this means, the proportion of a graft which may survive can be increased: this saves much time and discomfort, and of course expense, in the long run.

If part or all of the graft has actually died, then HBO will not work: in this case, HBO may help to maintain the viable part of the graft after the dead part has been removed at surgery.

Refractory osteomyelitis. Chronic inflammation of bone can follow on from trivial injuries, or from infection developing alongside orthopaedic implants (like rods and plates to support broken bones). Infection plays an important part in this process, but is not the primary problem. This disease develops usually, where there is some reason why the bone is not able to heal itself properly, such as poor blood supply, or another medical problem like diabetes, or steroid medication. The resulting pain and immobility are disabling, and can prevent the patient from getting on with their normal work or living. Surgery in the affected bone is difficult, because it may only spread the infection, or make another wound in the bone which it cannot heal properly.

HBO helps to resist infection, by providing extra oxygen to supply the white cells which normally destroy bacteria. The extra oxygen also promotes the activity of fibre-producing cells, which normally lay down the framework of new tissue. Later, it may also help in the growth of new blood vessels into the affected area, which helps to maintain the benefit of the earlier treatments.

However, necessary surgery (like the removal of infected implants and dead bone) cannot be avoided just because HBO is being used. The timing of surgery and the use of the right antibiotics should be planned at the same time as the HBO.

Radiation bone and soft tissue damage. This makes up the majority of non-emergency work in European HBO facilities. Intensive radiation, used to treat cancer, often in the area of the head and neck, may also damage normal bones and organs which lie in the line of the X-rays. This commonly involves the jaw; but it may also affect the pelvis, where the cancer has been in the internal organs. The X-rays damage the small blood vessels which run through the bone or soft tissue, so that a long-term process of shortage of oxygen and inflammation is set up. Over months or years after such treatment, the symptoms of tissue degeneration build up, with pain and limited movement, and sometimes with sticky fluid being leaked into the mouth or through the skin. This problem progresses relentlessly, unless it is sHyperbaric Oxygenped by aggressive treatment. Surgery in the affected tissues may make the situation worse, by making a new wound which the bone or tissue cannot heal properly. This problem is not primarily an infection; however, infection can rapidly develop in the affected tissue, which may make the situation suddenly much worse.

HBO works not only by helping the white cells in the affected tissue to resist infection. It also supplies the normal cells responsible for healing with enough oxygen to begin to work properly. In the long run, the gradient of oxygen level between the normal tissue and the affected tissue encourages new blood vessels to grow, and this helps to maintain the benefit of the earlier treatments.

Problem wounds. Wounds of any sort which are failing to heal, may benefit from HBO. The field where there is most evidence for this benefit is in the treatment of foot wounds in diabetes, where the problem may get worse for a variety of reasons, including poor blood supply and infection. In this situation, HBO must be used alongside other kinds of treatment, like appropriate antibiotics and surgery, and above all good foot care, to get the best results.
This list of applications of HBO is agreed by the European Committee for Hyperbaric Medicine, and by the European Underwater and Baromedical Society, as reasonable and justified by the evidence in the literature.