Role of intrathoracic pressure in changes in the greater and lesser circulation hemodynamics in patients with bronchial asthma

: The greater and lesser circulation hemodynamics was examined in 59 patients with bronchial asthma and 23 controls by tetrapolar rheography, kinetocardiography, and ultrasonic Doppler cardiography. Simultaneously measurements of intrathoracic pressure (ITP) were carried out with an esophageal controller. Reduced stroke index, increased total peripheral resistance of the vessels, and elevated systolic pressure in the pulmonary artery were revealed in the patients as against the controls. ITP values in asthmatics surpassed twofold those in the reference group. To reveal elevated ITP effects on the hemodynamics, the authors have examined the hemodynamic parameters during Valsalva's test (with elevation of oral pressure up to 25-35 mm Hg) in 16 reference subjects. The results evidence the leading role of elevated ITP on the greater and lesser circulation hemodynamics in asthma. Elevated ITP lowers the venous blood flow to the heart and reduces the preload thus decreasing the blood flow to the lesser circulation and not increasing the pulmonary artery systolic pressure.