Systemic hemodynamic effects of microspheres in conscious rats.

The effect of increasing quantities of carbonized microspheres (15 +/- 5 micrometer diam) on systemic hemodynamics was evaluated in 21 Sprague-Dawley, 6 normotensive Wistar-Kyoto (WKY), and 8 spontaneously hypertensive (SHR) male rats. Total cumulative injections of more than 100,000 microspheres produced significant systemic hemodynamic alterations manifested by decreased oxygen consumption, cardiac output, and mean arterial pressure; and by increased heart rate, total peripheral resistance, and arterial-venous blood oxygen content difference. There were no hemodynamic alterations characteristic of any rat species, and reproducibility of three separate injections of 20,000 microspheres in each rat was excellent.