Systemic hemodynamic and renal effects of unmodified human SFHS in dogs

Isovolumic exchange transfusion (25% of total estimated blood volume) was carried out in the anesthetized dogs using 9 g/dl of unmodified human stroma-free hemoglobin solution (SFHS). The objective was to determine the systemic hemodynamic, blood distribution and renal effects of SFHS over a 2-3 hour period post-exchange. At 30 minutes after the exchange, blood pressure rose from 114 +/- 117 to 133 +/- 22 mmHg, but this rise was not sustained thereafter. Mean pulmonary arterial blood pressure rose from 8 +/- 3 to 13 +/- 2 mmHg, and remained above the pre-exchange level up to 3 hours post-exchange. Cardiac output remained within normal limits. Significant flow-increments were seen at 30 minutes in heart, brain, liver, gut, and kidney, but these were also not sustained. A fall in glomerular filtration rate (GFR) occurred after the exchange and remained below the pre-exchange level. A reduction in urine flow at 150 minutes post-exchange was observed and was accompanied by a reduction in urinary electrolyte excretion. The findings suggest that the initial effects of the administration of unmodified stroma-free hemoglobin solution are those of peripheral vasoconstriction which does not appear to significantly restrict flow to the vital organs, such as heart and brain. Unmodified hemoglobin was found to cause a decrease in renal function.