There is no doubt that oxygen is one of the most popular drugs used in first aid and due to this fact arise some questions; What does this statistics comes from? Is it correct to belief in the effective-ness of high doses of oxygen? Does the specificity of the situation affect the effectiveness of this medicine? In that article I am going to consider the issue of oxygen therapy in first aid and I will try to answer the above questions.

In pre-hospital emergency, oxygen therapy has been considered for years a routine proce-dure for traumatic or sudden patients (such as acute coronary syndrome). Its purpose is to prevent hypoxemia . However, there is no evidence to support or refute the effectiveness of oxygen therapy As many studies have shown not every health threatening situation occurs with hypoxemia and re-quire this therapy. A great example are acute coronary syndromes (ACS) complicated by sudden cardiac arrest. Oxygen therapy with high oxygen flows is indicated for cardiopulmonary resuscitation in people with sudden cardiac arrest. This is due to the fact that hypoxemia develops rapidly, fol-lowed by hypoxia. Therefore, the use of oxygen therapy minimizes the risk of hypoxic brain damage, which will be a decisive factor in the patient's neurological prognosis. In a situation when, after suc-cessful resuscitation, circulation has returned, oxygen therapy should be performed at high oxygen flows until reliable saturation of arterial blood may be measured. At this point, a great tool is a pulse oximeter - a device for spectrophotometric measurement of oxygen saturation of hemoglobin while recording the pulse of the injured. When we can measure saturation, adjust the oxygen concentra-tion in the breathing mixture so that it takes values from 94 to 98%.

Where does this indication come from? Why not use oxygen all the time providing first aid since oxygen is a life-giving gas responsible for breathing in our cells? We should remember that the physiological concentration of oxygen in the inhaled air is about 21%, on expiration about 17% and to such conditions our body is adapted. One of the main threats is absorptive atelectasis- a situation in which air exhaled from the lungs causes leaching of nitrogen which prevents the collapse of the alveoli. Because of this, absorptive atelectasis may lead to shortness of breath or respiratory failure in the future. Another danger is for victims with chronic obstructive pulmonary disease (COPD). Due to chronic respiratory failure, the respiratory center in the medulla oblongata in COPD patients is adapted to high concentrations of carbon dioxide (in healthy people, breathing is stimulated by the increase of carbon dioxide in blood). This adaptation stimulates patients breathing by reducing arte-rial oxygen levels. Therefore, increased oxygen levels in COPD patients can lead to apnea and death despite high oxygen levels in the blood! Thus, the saturation of victims with COPD should be kept at 88-92%. That is why it is so important for rescuers of qualified first aid to interview the patient accordingly for e.g. in the SAMPLE scheme.

We should also remember about the harmfulness of high oxygen concentrations due to its oxidative properties, leading to the production of oxygen free radicals. Their chemical nature can cause a number of diseases after some time.

Despite the contraindications I mentioned for the use of oxygen therapy, especially those with high oxygen levels, there are many situations where oxygen therapy is necessary in first aid. Oxygen therapy in sudden cardiac arrest significantly reduces the risk of neurological complications and in those people who have drowned increases the effectiveness of cardiopulmonary resuscita-tion. One of the reasons is the fact that involuntary defensive reflexes of the respiratory muscles wanting to break the resistance of water in the respiratory tract very rapidly reduce hemoglobin oxy-gen saturation.

Summing up all qualified first aid rescuers should be able to use the oxygen therapy kit correctly. Nevertheless, every rescuer should know and understand the indications, contraindications, advantages and disadvantages of using oxygen as a medicine. Following Paracelus's words: "All things are poison, and nothing is without poison; but the dose makes it clear that a thing is not a poison." Remember that oxygen therapy has its side effects and can lead to numerous complications. This shows that oxygen therapy is not a universal method of treatment for all victims encountered in first aid. Oxygen should only be administered by properly trained rescuers who are able to monitor the effects of its administration.