Measurement of percent oxyhemoglobin by optical densitometry in perfluorocarbon supplemented blood.
A new generation of perfluorocarbon emulsions is being clinically evaluated as erythrocyte substitutes. However, the effect of perfluorocarbon emulsions on optical densitometric measurements of percent oxyhemoglobin (%O2Hb) has not been fully characterized. The purpose of this study is to quantify the effect of blood perfluorochemical concentration and hematocrit (Hct) on %O2Hb measurements. The authors hypothesize that perfluorocarbon emulsions affect the accuracy of %O2Hb measurements, and that the effect of perfluorochemical concentration and Hct on these measurements can be mathematically described. Porcine blood was used in this experiment. Blood with a Hct of 18% or 9% was mixed with a perfluorocarbon emulsion (Oxygent [AF0142]; Alliance Pharmaceutical Corporation, San Diego, CA). The concentrations tested were 0 g (Group I; n = 69 measurements for a Hct of 18%, and n = 35 measurements for a Hct of 9%), 0.73 g (Group II; n = 47 at 18%, n = 33 at 9%), 1.45 g (Group III; n = 46 at 18%, n = 30 at 9%), and 2.90 g (Group IV; n = 45 at 18%, n = 31 at 9%) of perfluorochemical per deciliter of blood (g PFC/dl). A tonometer was used to establish a range of oxygen tensions within each group while maintaining physiologic pH and PCO2. Error in %O2Hb measurements increases with higher perfluorochemical concentrations and lower Hct values. These errors in %O2Hb measurements are predictable; as such, an equation for correcting %O2Hb measurements in perfluorocarbon supplemented blood can be generated.
Murrah
C P
CP
Division of Cardiothoracic Surgery, University of Alabama at Birmingham 35294, USA.
Agnihotri
A K
AK
Spruell
R D
RD
Clymer-Hawk
J J
JJ
Ferguson
E R
ER
Wiley
J H
JH
Holman
W L
WL
D000818:Animals; D001802:Blood Substitutes / Q000737:chemistry; D003720:Densitometry / Q000379:methods*; D004655:Emulsions; D005069:Evaluation Studies as Topic; D005466:Fluorocarbons; D055095:Optics and Photonics; D010092:Oximetry / Q000379:methods*; D010108:Oxyhemoglobins / Q000032:analysis*; D013552:Swine
D001802:Blood Substitutes; D004655:Emulsions; D005466:Fluorocarbons; D010108:Oxyhemoglobins