Regional blood flow measurements with 15 micron and 50 micron microspheres in pregnant guinea-pigs.

Two sizes of microsphere were used to determine regional blood flow in pregnant guinea-pigs. Tissue perfusion measured with 50 micron microspheres was significantly greater than that measured with 15 micron microspheres in the small intestine, uterus, vagina, and placenta. A significantly larger proportion of the smaller microspheres passed through the systemic vasculature and could be detected in the lungs.