The conventional determination of pulmonary vascular resistance does not indicate which vascular segments contribute to the total resistance of the pulmonary circulation. Using measurements of pressure and flow, the reservoir-wave model can be used to partition total pulmonary vascular resistance into arterial, microcirculation, and venous components. Changes to these resistance components are ...

We have developed a pulmonary circulation laboratory exercise that effectively illustrates basic concepts typically taught in a graduate physiology curriculum. The demonstration uses an isolated, perfused rat lung model to delineate the mechanisms by which pulmonary vascular resistance can be altered either passively or in an active manner by contraction or relaxation of vascular smooth muscle....

Structural changes of the pulmonary circulation during the pathogenesis of pulmonary arterial hypertension remain to be fully elucidated. Although angiography has been used for visualizing the pulmonary circulation, conventional angiography systems have considerable limitations for visualizing small microvessels (diameters < 200 microm), particularly within a closed-chest animal model. In this ...

BACKGROUND The role, interplay, and relative importance of the multifactorial hemodynamic and myocardial mechanisms causing dysfunction of the Fontan circulation remain incompletely understood. METHODS AND RESULTS Using an MRI catheterization technique, we performed a differential analysis of pulmonary vascular resistance and aortopulmonary collateral blood flow in conjunction with global ven...

Investigations of the effect of pharmacological preparations on pulmonary hypertension in man are important for several reasons: from the potential therapeutic aspect; because these data may help to elucidate the regulation of pressure in the pulmonary artery; and finally because they may show whether pulmonary hypertension is reversible or irreversible. While the effect of reserpine on hyperte...

High levels of circulating catecholamines are found in the fetus, and fetal stress and birth induce a marked surge in catecholamine secretion. Little is known about the role of catecholamines on the fetal pulmonary circulation. To determine the effects of catecholamines on the pulmonary vascular tone, we tested the hemodynamic response to norepinephrine and dopamine infusion in chronically prep...

BACKGROUND Analysis of pulmonary status of pediatric patients in the postoperative phase of cardiac surgery. OBJECTIVE To assess pulmonary compliance and airway resistance in patients with congenital heart disease and pulmonary hyperflow submitted to surgical treatment with the use of extracorporeal circulation. METHODS Thirty-five patients were evaluated during surgery with measurements of...

Aging in the systemic circulation is associated with generalized endothelial dysfunction and increased oxidative stress, which are thought to contribute to the increased morbidity and mortality of cardiovascular diseases in the elderly. Previous studies have shown that pulmonary artery pressure and vascular resistance increase with normal aging in humans, yet age-related functional and phenotyp...

1 Pagnamenta A, Vanderpool RR, Brimioulle S, et al. Proximal pulmonary arterial obstruction decreases the time constant of the pulmonary circulation and increases right ventricular afterload. J Appl Physiol 2013; 114: 1586–1592. 2 Saouti N, Westerhof N, Helderman F, et al. Right ventricular oscillatory power is a constant fraction of total power irrespective of pulmonary artery pressure. Am J R...