Complicated bronchial asthma – bronchial asthma, aggravated by the consequences of this disease or associated infectious and inflammatory process in the lungs. The most common complications are: asthmatic status, emphysema, pneumothorax, mediastinal and subcutaneous emphysema, pulmonary heart, lung atelectasis. Emphysema, observed in 2/3 of patients with bronchial asthma, has different developmental periods. It can be acute reversible (formed during an attack due to obstruction of the bronchi) and chronic irreversible (formed during repeated exacerbations of asthma). The progression of concomitant chronic bronchitis causes secondary obstructive emphysema. Due to emphysema, the value of irreversible airway obstruction increases significantly, which worsens the course and prospects of therapy for bronchial asthma. In patients, the rhythm of breathing during an attack is disturbed, the excursion of the chest decreases, its configuration changes. The main link in the formation of the pulmonary heart in bronchial asthma is a diffuse violation of bronchial obstruction leading to a series of consecutive changes: a decrease in the clearance of the pulmonary capillaries and arterioles, an increase in pressure in the pulmonary artery, uneven ventilation of the lungs, alveolar hypoventilation, a reduction in the blood vessels of the lungs, arterial hypoxemia, and an increase in work right ventricle of the heart. Immediate allergy mediators (serotonin) are involved in the pathogenesis of pulmonary hypertension, and disorders of the androgenic and glucocorticosteroid functions of the adrenal cortex are observed. The presence of severe pulmonary hypertension, overload of the right ventricle of the heart in combination with the hypokinetic type of central hemodynamics, a change in pulmonary volumes (a steady increase in OOL and its relationship to OEL) are signs of a formed pulmonary heart. Segmental atelectasis can form during an acute attack of asthmatic status or in case of bronchial obstruction with Aspergillus fumigatus plug in case of allergic bronchopulmonary aspergillosis. The signs of this complication are different depending on the cause, location and severity of pulmonary collapse. The range of symptoms ranges from a mild cough with lack of physical data to tachypnea, cyanosis, displacement of the heart and mediastinum, elevation of the diaphragm on the side involved in the process. Persistent atelectases in the right middle lobe of the lung are manifested by constant or intermittent shortness of breath (right middle lobe syndrome). The diagnosis is established by x-ray examination. In unclear cases , additional research is indicated: bronchoscopy, bronchography. Bronchial asthma is also accompanied by hemodynamic disorders. During the attack in most patients, the pressure in the pulmonary artery system is increased, and the contractility of the right ventricle of the heart is reduced; sinus tachycardia (120 strokes or more in 1 min), various ECG disturbances, paradoxical pulse are noted. These disorders correspond to the severity of bronchial obstruction. During the period of remission, the pressure in the ductal artery remains elevated and disturbances in the phase structure of the heart remain (hypodynamia of the I – II degree of the right and left ventricles) depending on the severity of the course. Pneumothorax, mediastinal and subcutaneous emphysema can occur during asthmatic status. Treatment of complications is given according to the general rules of therapy for these conditions. Particular attention should be paid to the rehabilitation of the infectious and inflammatory focus in the lungs, which is most often represented by chronic obstructive bronchitis.