May be due to various reasons. When myocardial infarction is caused by heart failure and arising from it violation of the outflow of blood from the pulmonary vessels. In patients with hypertension or anemia, it occurs mainly due to the excitation of the autonomic nervous system, which leads to a redistribution of blood in the body and its accumulation in the pulmonary system. The same thing happens with injuries and diseases of the brain. With uremia, poisoning with toxic substances (chlorine, phosgene) in the development of pulmonary edema, the increased permeability of the walls of pulmonary capillaries plays a huge role. Regardless of the cause, pulmonary edema leads to impaired breathing and hypoxia. One of the first symptoms is shortness of breathing (shortness of breath), anxiety of the patient, increased heart rate. In the future, breathing becomes hoarse and even bubbling, a cough with a white or pink foamy sputum appears. This foam prevents the flow of air into the alveoli of the lungs, the patient develops oxygen deprivation, one of the signs of which is the cyanosis of the skin and mucous membranes (cyanosis).
First aid. First of all, it is necessary to restore the airway patency, remove foamy sputum. For this purpose, suction of sputum, inhalation of oxygen with vapors of alcohol, which is one of the effective antifoam agents, are used. To reduce blood filling in the pulmonary vessels, it is advisable to impose a wiring on the limbs. In this case, it is necessary to pinch only the venous vessels and maintain normal arterial blood flow. Therefore, putting a tourniquet, you should check the presence of a pulse on the artery below the tourniquet. In addition, to reduce the filling of the blood vessels of the lungs, diuretics are shown to lower blood pressure. With low blood pressure, these drugs should be used with great caution. Assisting patients with pulmonary edema, it should be aware of the various causes and mechanisms of its development. So, if, when a patient has a heart disease in an edema of the lungs, the administration of morphine is effective to reduce shortness of breath, then in case of pulmonary edema associated with a brain injury or disease, this drug is contraindicated. Therefore, starting to provide first aid, which consists of anti-foam therapy, oxygen inhalation and the imposition of harnesses, you must call a doctor who can figure out the causes and continue the correct intensive therapy.