Acute respiratory failure is a respiratory tract's damage, which can occur in people suffering from different diseases. Respiratory failure can be life-threatening, because in the lung is an accumulation of fluid. This fluid prevents the normal functioning of the lungs, because no air enters the human body. Respiratory failure occurs very quickly once the disease begins. Process, which is the cause of violation may continue for several weeks. If the lungs are developing cicatricial changes, it makes the ability of the lungs to pick up oxygen and eliminate carbon dioxide. In this disease of the tiny blood vessels follows the fluid that enters the lungs. This is due to exposure to toxins (poisons) that are allocated by the body in response to any occurring disorder or disease. Because of this, the lungs become like a wet sponge in the lungs cease to be a normal gas exchange and blood oxygen levels fall considerably. If the disease is serious, ie, its degree is hard, it can lead to scarring, fibrosis of the lungs. Cicatricial changes also complicate the process of gas exchange in the lungs.