(S-183) EFFECTIVENESS OF AUTOLOGOUS BLOOD DONATION (ABD) IN INCREASING TOTAL RBC VOLUME: COMPARING 1 UNIT (1U) VS. 2 UNITS (2U)

(S-183) Singbartl, G., Saturday 9:15

TITLE: EFFECTIVENESS OF AUTOLOGOUS BLOOD DONATION (ABD) IN INCREASING TOTAL RBC VOLUME: COMPARING 1 UNIT (1U) VS. 2 UNITS (2U)

AUTHORS: Guenter Singbartl, MD¹, Katrin Schueler, MD², Ehrenfried Roehrs, MD²AFFILIATION: ¹ENDO-Klinik Hamburg, Soltau, Germany; ²ENDO-Klinik Hamburg, Hamburg, Germany.

INTRODUCTION: ABD is thought being effective to reduce the need for homologous blood transfusions. However, those data rarely reveal information on increase in total rbc mass (+rbc) describing the efficacy of ABD, exclusively. As shown in our previous study, the conservative concept of 1U-ABD was not very effective in +rbc. This study now compares 1U- vs. 2U- ABD regarding +rbc.
METHODS: Data were taken from records of 704 pat. under- going ABD prior to hip- or knee arthroplasty. Pat. were considered eligible for ABD if presenting with compensated organ function (if necessary, with co-medication), if suitable for surgery (physical status rated according to ASA-score); and if hb- value 115 g per ltr. Blood volume (BV) was calculated according to (1), systemic hct by venous hct*0.9, and +rbc by praeop. rbc mass (in-vivo plus ex-vivo) minus init. rbc mass before ABD. Statistical analysis included test for normal distribution, t-test/U-test/Wilcoxon-test, ANOVA/Friedman- test, Chi²-test, rank-correlation according to SPEARMAN, univariate regression analysis, and Bonferroni correction when appropriate. Data are given as mean±SD. Statistical significance was set at p<0.05 (*).
RESULTS: Tab. 1 gives relevant data. In 2U-ABD (n=265), 37.4% of the patients generated +rbc equal to 2U of rbc, and in 1U-ABD (n=439) 57.2% of the patients generated +rbc equiva- lent to 1U. The more aggressive 2U-ABD resulted in shortening of interval between donation and operation (IDOP) for generating 1U of rbc compared to 1U-ABD. Regression analysis showed IDOP most important for +rbc.

Tab. 1	1U-ABD	2U-ABD	p
Age (yrs)	63.6±11.0	61.3±10.3	*
BV (ltr.)	4.5±0.7	4.8±0.8	*
hct init (%)	35.6±2.9	36.9±2.8	*
rbc mass init (l)	1.6±0.3	1.8±0.4	*
IDOP (days to op.)	21.8±9.5	16.3±6; 19.5±7	*
hct praeop (%)	35.2±3	35.5±3.1	ns
+rbc mass (ml)	175±95	317±112	*
IDOP until reaching +rbc 190ml	> 3weeks	< 3weeks	*

Influence of gender on +rbc vanished if +rbc was correlated to the patient's BV. Age itself had no impact on +rbc.

DISCUSSION: 2U-ABD is much more effective in +total rbc mass. With identical IDOPs +rbc is greater for 2U-ABD than for 1U-ABD, stressing the role of BV/rbc mass donated by ABD for generating +rbc (by stimulating erythropoiesis).
(This study contains relevant data of K.S' MD-thesis.)
REFERENCES:

1) NADLER et al. 1962. Surgery 51:224-232.