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Studies on blood substitutes based on hemoglobin and perfluorocarbon
G P Biro1, N Jing, P J Anderson
1University of Ottawa, Department of Physiology, Ontario, Canada.
Summary
Free hemoglobin infusions in dogs did not improve oxygen supply but caused vasoconstriction, particularly impacting kidney function. Coronary effects were overridden, but renal concerns remain for stroma-free hemoglobin solutions.
Area of Science:
- Physiology
- Pharmacology
- Nephrology
Background:
- Stroma-free hemoglobin (SFHS) preparations can cause vasoconstriction in isolated organs.
- The in vivo physiological significance of this vasoconstriction is not well understood.
Purpose of the Study:
- To investigate if plasma free hemoglobin contributes to oxygen supply in vivo.
- To determine if excessive vasoconstriction from SFHS leads to functional impairment in dogs.
Main Methods:
- In vivo dog experiments were conducted.
- Hemodynamic parameters, arterial blood pressure, and tissue oxygen supply were monitored.
- Renal function and vasoconstriction were assessed after SFHS administration.
Main Results:
- Unmodified SFHS caused elevated blood pressure and vasoconstriction in skeletal muscle and renal cortex without improving oxygen supply.
- Glutaraldehyde cross-linked SFHS worsened hypotension and caused renal vasoconstriction and functional impairment in hypotensive dogs.
- Coronary autoregulation appeared to counteract in vitro vasoconstrictor effects.
Conclusions:
- In vivo coronary mechanisms can overcome SFHS vasoconstrictor potency.
- Renal vasoconstriction and functional impairment caused by SFHS containing unmodified hemoglobin are significant concerns.
- Free hemoglobin's role in oxygen delivery in vivo is limited under these conditions.