June 6, 2024 Author: Claúdia Febra In hyperbaric oxygen therapy oxygen is inhaled at a concentration of 100% in an environment where the pressure is two to three times higher than atmospheric pressure. Atmospheric air is composed of different gases, mainly nitrogen and oxygen, the latter in a concentration of 21%. Under normal conditions, inspired air has a similar composition to atmospheric air. When the concentration of oxygen in the inspired air increases and its administration is carried out in an environment with a pressure higher than atmospheric pressure - as happens in hyperbaric oxygen therapy - the concentration of oxygen in the lungs increases and, therefore, the oxygen in the blood and its amount distributed to the body tissues also increases. The development of hyperbaric treatments, with oxygen (oxygen therapy) and other gas mixtures, was driven by military medicine given its successful application in decompression sickness associated with professional diving. From the middle of the 20th century, hyperbaric oxygen therapy began to be used in clinical practice, after its favorable effects related to anti-ischemic, anti-hypoxic, anti-edematous, anti- infections and promoting healing properties were demonstrated. Hyperbaric chambers Hyperbaric oxygen therapy treatments are carried out in sealed chambers made of materials resistant to high pressure. The pressure of hyperbaric chambers that have scientifically proven clinical effects must be equal to or greater than 2 atmospheres. The use of pressures below 2 atmospheres does not allow obtaining the clinical effects associated with the benefits of hyperbaric oxygen. There are several types of hyperbaric chambers, the most used in clinical practice are multi-occupant allowing several people to be treated in the same session and to be monitored by health professionals throughout the sessions. Oxygen is administered through masks or other appropriate devices and the exhaled air is directed to the outside of the chamber, keeping the composition of the ambient air constant. Hyperbaric oxygen therapy is carried out in several sessions. The number and duration of sessions depend on the clinical situation of each patient, with 20-40 sessions being more common. A hyperbaric oxygen therapy session usually does not exceed 2 hours. Indications and contraindications for hyperbaric oxygen therapy Almost all problems in which hyperbaric oxygen therapy may be indicated have in common being caused, aggravated or maintained by lower than desirable oxygen concentrations in the blood and tissues. This can happen due to: Decrease in the oxygen transport capacity of the blood; Obstruction to the arrival of oxygen to tissues and cells; Inability of the body tissues and cells to use oxygen. In most cases, oxygen therapy is part of a plan that includes other treatment modalities. Individual assessment by doctors with expertise in hyperbaric medicine and treatment programming together with the rest of the healthcare team involved in monitoring each patient is mandatory. Examples of situations in which hyperbaric oxygen therapy may be indicated are: Severe infections of the skin and soft tissues, caused by some types of bacteria; Severe bone infections, whether spontaneous or arising as a complication of other treatments, such as surgery with prosthetic material or radiotherapy; Gangrene and wounds that are difficult to heal, for example associated with diabetes and burns; Skin, muscle or bone grafts with difficulty healing; Injuries resulting from radiotherapy, such as tissue radiation necrosis or radiation prostatitis; Trauma with tissue crushing; Sudden deafness; Carbon monoxide poisoning, accidental ingestion of hydrogen peroxide, cyanide poisoning; Decompression sickness resulting from diving; Arterial gas embolism secondary to surgery or medical procedures. Almost every patient can undergo hyperbaric oxygen therapy, although some relative contraindications require a rigorous case-by-case assessment , such as, for example, obstructive pulmonary disease, respiratory and sinus infections, uncontrolled fever, recent ear or chest surgery, history of seizures. Complications of hyperbaric oxygen therapy Hyperbaric oxygen therapy is a safe and well-tolerated treatment. Possible complications are rare, usually reversible and include: Injuries related to pressure variations, most often middle ear barotrauma. Injuries associated with oxygen toxicity (for example, convulsions and changes in lung function), the occurrence of which is minimized by ensuring strict compliance with the duration of sessions and maximum pressure. Individual problems of claustrophobia associated with staying inside the chamber. Carrying out hyperbaric oxygen therapy also requires strict compliance with various safety measures and instructions from the responsible healthcare team , which aim to avoid accidents related to the presence of combustible compounds (oxygen) and increased temperature and pressure. Source Albuquerque e Sousa JG. Oxigenoterapia hiperbárica. Perspetiva história, efeitos fisiológicos e aplicações clínicas. Med Int 2007 14:219-26. Crawford Mechem C, Manaker S. Hyperbaric oxygen therapy . The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
