title: Changes in venous return parameters associated with univentricular Fontan circulations.
abstract: To clarify the physiology of venous return (Q(vr)) in Fontan circulations, venous return conductance (G(vr)) and mean circulatory filling pressure (P(mcf)) were determined in pentobarbital sodium-anesthetized pigs. Relationships between Q(vr) and right (biventricular, n = 8) or left (Fontan, n = 8) filling pressures are described by straight lines with significant correlation coefficients. Estimated P(mcf) values were correlated with observed P(mcf) values in either circulations (P </= 0.02). G(vr) was smaller in Fontan than in biventricular circulations (4.51 +/- 0.36 vs. 7.83 +/- 0.69 ml. min(-1). kg(-1). mmHg(-1), P = 0.002) and inversely correlated with pulmonary vascular resistances in Fontan circulations (P = 0.01). Estimated P(mcf) (20.5 +/- 1.4 vs. 11.1 +/- 0.9 mmHg, P = 0.001) and observed P(mcf) (21.8 +/- 1.3 vs. 10.6 +/- 0.8 mmHg, P < 0.001) were higher in Fontan versus biventricular circulations, respectively. Pulmonary artery pressure in Fontan circulations was correlated with either P(mcf) (P < or = 0.04). We conclude that in Fontan circulations 1) pulmonary vascular resistances induce a proportional decrease in G(vr); and 2) volume loading, while increasing P(mcf) (similar to pulmonary artery pressure), allows the gradient for Q(vr) to increase and maintains systemic blood flow at a biventricular level.
authors.affiliation: Department of Cardiovascular and Pediatric Cardiac Surgery and Experimental Surgical Laboratory, Marie Lannelongue Hospital, Paris-Sud University, 92350 Le Plessis Robinson, France. mace@ccml.com
authors.forename: L
authors.initials: L
authors.lastname: Macé
authors.forename: P
authors.initials: P
authors.lastname: Dervanian
authors.forename: A
authors.initials: A
authors.lastname: Bourriez
authors.forename: G M
authors.initials: GM
authors.lastname: Mazmanian
authors.forename: V
authors.initials: V
authors.lastname: Lambert
authors.forename: J
authors.initials: J
authors.lastname: Losay
authors.forename: J Y
authors.initials: JY
authors.lastname: Neveux
mesh_terms: D000818:Animals; D001011:Aorta / Q000502:physiology; D001775:Blood Circulation / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D018729:Fontan Procedure; D006352:Heart Ventricles / Q000503:physiopathology* / Q000601:surgery; D006439:Hemodynamics / Q000502:physiology; D013552:Swine; D014690:Venous Pressure / Q000502:physiology