Influences of nonpulsatile pulmonary flow on pulmonary function. Evaluation in a chronic animal model.

To clarify the influences of nonpulsatile blood flow on the physiologic function of the lung, we established nonpulsatile pulmonary circulation with a centrifugal pump in a chronic animal model (adult goats, n = 6). As the initial phase, a pulsatile right ventricular assist device was implanted to bypass the whole blood supply from both the right atrium and right ventricle to the pulmonary artery. After 2 weeks of pumping, the pulsatile pump was replaced with a centrifugal pump without anesthesia, and nonpulsatile pulmonary circulation was instituted. In this experimental model, no significant change was observed in either mean pulmonary arterial pressure or pulmonary vascular resistance index during the pulsatile pumping compared with that on the fourteenth day of nonpulsatile pumping. Blood gas data, extravascular lung water content, and serum level of angiotensin-converting enzyme were maintained within normal ranges. There was also no significant change in the ventral to dorsal blood perfusion ratio of the lower lobe of the right lung. These results indicate that pulmonary functions are not affected by nonpulsatile pulmonary circulation for a period of 14 days in this animal model.