Hyperbaric oxygen therapy (synonyms: HBO therapy, hyperbaric oxygenation, HBO2, HBOT, whole-body pressure chamber therapy; English : hyperbaric oxygen therapy) is a therapeutic procedure used by various branches of medicine, which can be used, among other things, to treat carbon monoxide poisoning. The basic principle of the procedure is based on the inhalation of oxygen at a higher partial pressure than the normal atmospheric pressure. To achieve this, it is necessary for the patient to be in a special pressure chamber. The procedure can be used in acute therapy as well as for the treatment of chronic diseases. Early hyperbaric oxygen therapy plays an important role in intensive care therapy of arterial gas embolism, among others. In osteomyelitis (bone marrow inflammation), on the other hand, the procedure is used when other therapeutic options prove inadequate for treatment.
Indications (areas of application)
The level of evidence (proof of efficacy of treatment) for the use of hyperbaric oxygen therapy varies depending on the indication. However, treatment using hyperbaric oxygen therapy alone is never indicated. The particular indication determines the positive pressure required for application, the duration, and the total number of treatments. High level of evidence
- Air or gas embolism-both iatrogenic (caused by medical procedures) and trauma-induced gas embolism can be treated by hyperbaric oxygen therapy.
- Carbon monoxide poisoning – carbon monoxide poisoning is an established indication for the use of hyperbaric oxygen therapy. Treatment is particularly necessary if cyanide poisoning is also present.
- Clostridial myositis (muscle inflammation) and myonecrosis (death of muscle) – the bacterium Clostridium perfringens can cause gas gangrene (synonyms: Gas gangrene, gas edema, gas phlegmon, Clostridium myositis and cellulitis, clostridial myonecrosis, malignant edema), which can lead to a life-threatening systemic reaction in addition to myositis and myonecrosis. Hyperbaric oxygen therapy is a critical factor in treatment, along with radical limb amputation.
- Compartment syndrome – increased postoperative or posttraumatic pressure in a tissue box can cause compartment syndrome, particularly in the lower leg.
- Posttraumatic reperfusion syndrome – due to the accumulation of deoxygenated and very acidic blood, tissue damage occurs. Treatment by means of hyperbaric oxygen therapy is possible.
- Decompression sickness – decompression sickness usually results from exposure to overpressure or from relieving pressure too quickly. Since the clinical picture occurs most often when diving, it is also called diver’s disease (synonym: caisson disease).
- Severe anemia (exceptional anemia) – hyperbaric oxygen therapy is intended to improve the reduced oxygen supply to the tissues.
- Osteomyelitis (bone marrow inflammation) – in the presence of refractory osteomyelitis, the use of hyperbaric oxygen therapy is possible.
- Critical skin grafts and myocutaneous flaps – in plastic hand and reconstructive surgery, the procedure is used especially for skin and muscle flaps, where the chance of healing is reduced.
- Burns – the use of hyperbaric oxygen therapy in burns is an established indication.
- Inflammatory bowel disease (IBD) – in Crohn’s disease and ulcerative colitis, which can be associated with severe complications, the use of the procedure may be useful.
Low level of evidence
- Intracranial abscess (accumulation of pus inside the skull).
- Acute hearing loss
- Acute tinnitus (ringing in the ears)
- Diabetic foot (diabetic foot syndrome) – in patients with diabetic foot ulcers (foot ulcers), hyperbaric oxygen therapy improves the ulcers (ulcers) in the short term, but not in the long term [The procedure is approved in 2017 as a complementary method in SHI-accredited care].
- Circulatory disorders of the retina (retina).
- Aseptic bone necrosis (synonyms: aseptic osteonecrosis; abbreviation: AON, AKN; English aseptic osteonecrosis or aseptic bone necrosis) – collective name for a bone infarction due to various causes without the presence of an infection (aseptic).
Contraindications
- Bronchial asthma
- Emphysema (pulmonary hyperinflation)
- Pulmonary tuberculosis
- Pneumothorax (accumulation of air next to the lungs).
- Thoracotomy (opening of the chest)
- High-grade cardiac arrhythmia
- Severe coronary artery disease (CAD)
- Fresh myocardial infarction (heart attack)
- Vitia (congenital heart defect)
- Higher-grade heart failure (cardiac insufficiency)
- Hypertension grade III (severe form of hypertension).
- Pacemakers not suitable for pressure chamber (HSM) (pacemaker (PM; English “pacemaker”).
Before therapy
Before therapy, in acute life-threatening cases, it is necessary to check whether stabilization of vital signs is not required before hyperbaric oxygen therapy. The presence of contraindications must be ruled out.
The procedure
At atmospheric pressure under normal conditions, when air is inhaled, much of the oxygen absorbed by the body is bound to hemoglobin. In this bound form, oxygen can be transported from the lungs to the systemic circulation. Hyperbaric oxygen therapy is used to improve the oxygen supply to the tissues, where an increase in oxygen partial pressure can occur under conditions of hyperbaric oxygenation. By this increase of the oxygen partial pressure it can be achieved that the part of the oxygen bound to the hemoglobin is not consumed and also on the venous side there is an oxygen saturation (SpO2) of the hemoglobin of 100%. The use of hyperbaric oxygen therapy to improve wound healing is based on increasing the oxygen supply in the wound healing area. An increased oxygen supply in the wound margin and wound bed is necessary for proliferation and the release of growth factors and cytokines (mediators). In the presence of carbon monoxide poisoning, oxygen is displaced from hemoglobin because carbon monoxide has a higher binding affinity to hemoglobin than oxygen. Under normobaric conditions, competitive displacement of oxygen from hemoglobin occurs because of this. Thus, insufficient oxygen can reach the cells. However, hyperbaric oxygen therapy can displace carbon monoxide from oxygen via this competitive mechanism. For example, a therapy session for diabetic foot syndrome lasts between 45 and 120 minutes and is performed daily over a period of several weeks.
After therapy
Depending on the indication, various additional therapy-supporting procedures must be used. Furthermore, the therapeutic success of the procedure must be reviewed.
Possible complications
- Lung injury – damage to the lungs from oxygen in the form of acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) may result from hyperbaric oxygen therapy. Thus, the damage pattern resembles a barotrauma (pressure trauma) during mechanical ventilation.
- Seizure – as a complication of hyperbaric oxygen therapy, cerebral seizure (seizure of the brain) may occur. This very rare complication represents a consequence of exposure to a high “dose” of oxygen.
- Myopia – myopia can occur as a result of exposure to oxygen. This complication is also a consequence of increased oxygen concentration. However, the complication is a temporary phenomenon that is completely reversible.
- Nausea and vomiting
- Tympanic membrane damage – barotrauma of the tympanic membrane may result from the procedure. Overall, this complication occurs relatively frequently. Usually, the eardrum damage heals within a few days even without therapy.
