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[Colloid substitutes and hematocrit measurement by micromethods]
J M Vedrinne1, O Gentilhomme, D Bussery
1Département d'Anesthésie-Réanimation IV, Hôpital Edouard-Herriot, Lyon.
Annales Francaises D'Anesthesie Et De Reanimation
|January 1, 1991
Summary
Centrifugation and resistivity methods for measuring blood haematocrit were evaluated. Resistivity methods showed significant underestimation with gelatin dilutions, unlike centrifugation.
Area of Science:
- Biomedical Engineering
- Clinical Chemistry
- Hematology
Background:
- Accurate hematocrit measurement is crucial for clinical diagnostics.
- Dextran and gelatin are used as plasma expanders, potentially affecting blood properties.
- Evaluating alternative hematocrit measurement techniques is important for clinical practice.
Purpose of the Study:
- To assess the reliability of centrifugation and resistivity methods for measuring hematocrit in blood diluted with dextran or gelatin.
- To compare these methods against a reference standard (Coulter counter).
Main Methods:
- Blood samples from healthy subjects were diluted with varying concentrations (0-50%) of dextran or gelatin.
- Hematocrit was measured using minicentrifuge (Compur M 1100), Stat-Crit (resistivity), and Coulter counter (reference).
Main Results:
- All methods showed similar hematocrit values for undiluted blood.
- Dextran dilutions resulted in a slight, non-significant underestimation of hematocrit across all methods.
- Gelatin dilutions showed no significant difference with centrifugation but up to 15.5% underestimation with resistivity (p<0.05).
Conclusions:
- Resistivity methods for hematocrit measurement are unreliable with gelatin-containing fluids due to charge interference.
- Centrifugation remains a reliable method for hematocrit measurement even with dextran or gelatin.
- Avoid resistivity-based hematocrit measurements in patients receiving fluid modified gelatin.