INPUT IMPEDANCE OF FETAL AND NEONATAL LEFT PULMONARY ARTERIAL CIRCULATION

Fetal and neonatal pulmonary circulation.

During fetal life, gas exchange is carried out in the placenta. The lung does not have a physiological role, apart from possible metabolic functions which include secretion of hormones, enzymatic conversion of inactive substances to functional hormones, and degradation of active materials to inactive metabolites. Blood flow through the lungs is quite low during fetal life; most of the systemic ...

Clinical significance of pulmonary arterial input impedance.

C Cl li in ni ic ca al l s si ig gn ni if fi ic ca an nc ce e o of f p pu ul lm mo on na ar ry y a ar rt te er ri ia al l i in np pu ut t i im mp pe ed da an nc ce e Pulmonary arterial input impedance excites the attention of few clinicians, but there are compelling reasons why they should be more interested in this subject. Physicians are well-versed in the intricacies of pulmonary vascular re...

Form and function of fetal and neonatal pulmonary arterial bifurcations.

Bifurcation is a basic form of vascular connection. It is composed of a parent vessel of diameter d(0), and two daughter vessels, d(1) and d(2), where d(0) > d(1) >/= d(2). Optimal values for the bifurcation area ratio, beta = (d(1)(2) + d(2)(2))/d(0)(2), and the junction exponent, x, in d(0)(x) = d(1)(x) + d(2)(x), are postulated to be universal in nature. However, we have hypothesized that th...

Input impedance of the systemic circulation.

Input impedance of the pulmonary arterial system in normal man. Effects of respiration and comparison to systemic impedance.

Input impedance of the pulmonary arterial system was determined in 10 subjects undergoing elective cardiac catheterization. No cardiovascular or pulmonary disease was found in these patients. In five of the subjects, systemic arterial impedance was also obtained, so that both systems could be compared. Pulmonary and systemic peripheral resistances were 79 +/- 9 dynes sec/cm5 (mean +/- SEM) and ...