Effect of oxygen affinity on systemic perfusion and brain tissue oxygen tension after extreme hemodilution with hemoglobin-starch conjugates in rats.
OBJECTIVE
To determine the oxygen affinity for optimal tissue oxygen delivery with a hemoglobin-hydroxyethyl starch conjugate (HRC 101).


METHODS
Anesthetized rats were hemodiluted (180 ml kg(-1)) with low (P(50) approximately 70 mmHg) or high affinity (P(50) approximately 14 mmHg) HRC 101 at hemoglobin (Hb) concentrations near 100 or 70 g l(-1) (n = 6-8). Hippocampal tissue oxygen tension (P(Br)O(2)), blood flow, arterial blood gases, Hb, hematocrit (Hct) and lactate were measured. Data (mean +/- SD) were analyzed by two-way ANOVA.


RESULTS
Hemodilution reduced the hematocrit to 1 +/- 1% in all groups. P(Br)O(2) was best maintained after hemodilution with low affinity HRC 101 at Hb 100 and 70 g l(-1) (25.2 +/- 7.6 and 16.6 +/- 8.3 torr, respectively). P(Br)O(2) decreased (9.5 +/- 9.3 torr, P < 0.05) and serum lactate levels increased (5.0 +/- 1.7 mmol l(-1), P < 0.05) following hemodilution with the high affinity HRC 101 (Hb 100 g l(-1)).


CONCLUSIONS
HRC 101 with a lower oxygen affinity favored tissue perfusion and maintained P(Br)O(2) after near complete blood volume exchange in rats.
Hare
Gregory M T
GM
Departments of Anesthesia and Critical Care, Cara Phelan Centre for Trauma Research, The Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, University of Toronto, Toronto, ON, M5B 1W8, Canada.
Liu
Elaine
E
Baker
Andrew J
AJ
Mazer
C David
CD
D000704:Analysis of Variance; D000740:Anemia / Q000097:blood / Q000188:drug therapy; D000818:Animals; D001784:Blood Gas Analysis; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D006400:Hematocrit; D006438:Hemodilution / Q000379:methods*; D006454:Hemoglobins / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use*; D006624:Hippocampus / Q000098:blood supply / Q000187:drug effects* / Q000378:metabolism*; D006895:Hydroxyethyl Starch Derivatives / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D008970:Molecular Weight; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution
C522784:HRC 101; D006454:Hemoglobins; D006895:Hydroxyethyl Starch Derivatives; D019344:Lactic Acid; D010100:Oxygen