PULMONARY VENOUS BLOOD FLOW

Pulsatile characteristics of blood flow in major pulmonary veins were determined from chronically implanted dogs. From these data, five distinct positive flow maxima or waves are proposed to describe the variety of waveforms observed over a cardiac cycle. These five waves appear to change in amplitude and relative position among dogs, with respiration and under physiologic stress, and thereby permit an explanation of the different patterns that have been reported by other investigators. The general appearance of the flow waveform is particularly sensitive to heart rate. Four of the five flow waves are attributed to left heart action. One wave corresponds to the effects of right ventricular ejection transmitted through the pulmonary vascular bed. Limited data from respiration maneuvers and pharmacologic intervention provide changing waveform patterns which support these conclusions. Dissimilar waveforms were recorded simultaneously from some pairs of lobar veins. (Author)