Experiments were done in anesthetized rats to determine systemic hemodynamic and renal functional effects of isovolemic exchange transfusion with either 5% albumin or hemoglobin cross-linked with bis (3,5-dibromosalicyl) fumarate (XLHb) in volumes ranging from 1 to 6.3 ml.100 gm-1. Hematocrit decreased in proportion to increasing exchange volumes with either fluid. Exchange with increasing volumes of albumin led to progressive decreases in blood pressure. Exchange of 1 ml.100 gm-1 of XLHb was associated with an increase in blood pressure, whereas with larger exchanges, blood pressure returned to and was maintained at control values even for exchanges as large as 6.3 ml.100 gm-1. An increase of similar magnitude in glomerular filtration rate occurred with both fluids. Net and fractional sodium excretion (FENa) increased significantly with both transfusion fluids; the increase was significantly larger for XLHb than for albumin. Maximal FENa excretion with albumin was about 8% but exceeded 6% with XLHb. Pretreatment with indomethacin (5 mg.kg-1.day-1 for 3 days) did not blunt the diuresis that occurred with an exchange of 2 ml.100 gm-1 XLHb. It is concluded that 5% XLHb, as compared with 5% albumin, better supports systemic blood pressure, especially as exchange volume increases, possibly as a result of hemoglobin-induced increased vascular tone. Although a decrease in hematocrit may play a role in the diuresis observed with either fluid, the greater diuresis with XLHb must be due to some additional factor; the mechanism does not appear to involve prostaglandins.
Animals Aspirin