Preoperative autologous blood donation - part I. Only two clinical parameters determine efficacy of the autologous predeposit.
OBJECTIVE
To improve efficacy of preoperative autologous blood donation (i.e. increase in total RBC-mass) it is important to know those clinical parameters that are of decisive impact for it.


METHODS
Prospective study in 704 patients scheduled for major orthopaedic surgery. Donation of either one or two separately collected RBC-units, and calculation of increase in RBC-mass by the HCT-method. Qualitative statistical analysis by multiple univariate analysis of variances, correlation analysis with Pearson, multiple linear regression analysis. Quantitative statistical analysis by t-/U-test; P<0.01(n >or= 100), and P<0.05 (n <100), respectively.


RESULTS
Two parameters were demonstrated of decisive impact to increase in RBC-mass to preopeative autologous blood donation (PABD) (P<0.000): first, time interval between preoperative autologous blood donation and surgery, that correlated positively with efficacy; second, haematocrit-level at predeposit-session that correlated negatively with efficacy. The highest level of RBC-regeneration reached was observed four weeks after last blood donation (one unit:146.6+/-85.2 mL; two units: 297.4+/-78.6 mL). Patients with an anaemic initial haematocrit (females: <or=37%; males <or=40%) generated more RBC (*P<0.05) than non-anaemic patients (one unit: females, 148.3+/-67.6 vs 73.8+/-65.8 mL; males, 170.5+/-81.6 vs 77.0+/- 93.9 mL. Two units: females, 295.0+/-58.5 vs 226.0+/-79.7 mL; males, 299.9+/-82.5 vs 234.6+/- 107.5 mL).


CONCLUSIONS
To improve efficacy of preoperative autologous blood donation, a time interval between (last) autologous predeposit and surgery of at least 4 weeks should remain for efficacious RBC-regeneration; together with an acute and strong decline in haematocrit due to the autologous predeposit to push erythropoiesis as efficaciously as possible.
Singbartl
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AIT - Institut fuer Anaesthesie, Intensiv- und Transfusionsmedizin, ENDO-Klinik Hamburg GmbH, Hamburg, Germany. g.singbartl@gmx.de
D000368:Aged; D001804:Blood Transfusion, Autologous; D004906:Erythrocyte Count; D005260:Female; D006400:Hematocrit; D006801:Humans; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures; D011446:Prospective Studies