Transient analysis of cardiopulmonary interactions. I. Diastolic events

摘要: The etiology of the fall in left ventricular stroke volume (LVSV) with negative intrathoracic pressure (NITP) during inspiration has been ascribed to a reduction LV preload. This study evaluated effects NITP and without airway obstruction confined early (ED), mid- (MD), or late diastole (LD) on subsequent LVSV, anteroposterior (AP), right-to-left (RL) aortic diameters (DAO) (series I, n = 6) as well phasic arterial blood flow out thorax II, anesthetized dogs. Transient was obtained by electrocardiogram-triggered phrenic nerve stimulation. In series applied for 60% obstructed caused decreases LVSV ED [-7.7 +/- 3.2% (SE) NS], MD (-11.7 3.9%, P less than 0.05), LD (-14.6 1.5%, 0.01) associated significant increases end-diastolic pressures relative both atmospheric esophageal LD. increased DAO(AP) DAO(RL), resulting diastolic cross-sectional area an average 6.1-8.3% (P 0.01). Similar changes were seen unobstructed NITP. diminished antegrade carotid artery and/or descending run off all retrograde flows observed more half animals consistent diameters. We conclude that decrease can 1) diminish ensuing presumptively reducing preload interdependence; 2) distend aorta; 3) independent cardiac performance; 4) cause transient flow. aorta and, presumably, vascular compartment be viewed elastic container driven pressure.