Ventilatory effects on pulmonary vascular inflow and outflow patterns.

Ventilation of an isolated lung lobe modifies the rate of inflow into its pulmonary artery (Murao and Rodbard, 1971). The present studies show that ventilation also influences the rate of outflow from the pulmonary vein in a manner which differs significantly from the effects on the rate of inflow into the pulmonary artery. Since this difference between instantaneous inflow and outflow rates affects the calculation of vascular conductance (resistance) and its interpretation we have compared and analysed the effects of ventilation on simultaneous flow patterns in the pulmonary artery and vein.