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TISSUE OXIDATIVE METABOLISM AFTER EXTREME HEMODILUTION WITH PEG CONJUGATED HEMOGLOBIN
Author(s) -
Cabrales Pedro
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.lb575
Subject(s) - chemistry , hemoglobin , peg ratio , dextran , blood substitute , oxygenation , hematocrit , red blood cell , biochemistry , medicine , finance , economics
NADH fluorometry was used as a non‐invasive technique to monitor changes in the energy state of intact tissue in the hamster window chamber model. Acute moderate isovolemic hemodilution was induced by two isovolemic hemodilution steps using 6% dextran 70kDa to 18% hematocrit (Hct). The protocol continued with an exchange transfusion to reduce erythrocytes to 75% of baseline (11% Hct) using either polyethylene glycol (PEG) maleimide conjugated hemoglobin 4 g/dl (PEG‐Hb) or a dextran (Dex70, 6 g/dl dextran 70 kDa). Systemic parameters, microvascular perfusion, functional capillary density, intravascular and interstitial oxygen tensions and intracellular NADH fluorescence were monitored. Blood pressure after extreme hemodilution was statistically significantly reduced for Dex70 when compared to PEG‐Hb. While microvascular blood flows were not different, the functional capillary density was significantly higher for PEG‐Hb compared to Dex70. Intravascular PO2 for PEG‐Hb was higher in arterioles compared to Dex70, but not different for either tissue or venular PO2. Cellular energy metabolism in the tissues was improved with PEG‐Hb. Hhemodilution to 18% Hct brings tissue oxygen delivery to the verge of inadequacy. Extreme hemodilution to 11% Hct produces tissue and anoxia, and high oxygen affinity PEG‐Hb (P50: 4 mmHg) and partially decreases anaerobic metabolism.