Effects of intraoperative blood salvage on leukocyte recruitment to the endothelium.
BACKGROUND
The contamination of salvaged wound blood with activated leukocytes has been suspected to play a role in leukocyte-mediated tissue injury by increased adhesion to the endothelium. To verify this hypothesis, the authors performed a clinical study to examine the effects of blood salvage on leukocyte-endothelial interactions.


METHODS
Expression of L-selectin, CD18, and CD11b and leukocyte adhesion to activated endothelium from human umbilical veins were measured in 25 patients undergoing major orthopedic surgery. Adhesion of fluorescently labeled leukocytes was examined in a flow chamber at shear rates of 50-1,600 s. Comparisons were made between samples from venous blood and from processed salvaged wound blood (SWB).


RESULTS
At 30% hematocrit, SWB contained 2,162 +/- 147 leukocytes/microl. In comparison with venous blood, CD11b was up-regulated in SWB 1.3- to 3.6-fold on monocytes and neutrophils, whereas L-selectin and CD18 decreased on monocytes by 53% and 15%, respectively (P < 0.05). Despite up-regulation of CD11b, firm adhesion was significantly reduced by 74-76% in SWB. Rolling fractions and rolling velocities were significantly higher in SWB, and their relation to shear rate was markedly altered (P < 0.01). In addition, adherent leukocytes from SWB were significantly less resistant to increments of shear rate than leukocytes from venous blood (P < 0.01).


CONCLUSIONS
Despite up-regulated CD11b, integrin-mediated adhesion is markedly impaired in salvaged blood. Therefore, the effect of blood salvage cannot be predicted from cell surface expression but rather from functional assays. The former hypothesis, that leukocytes from SWB aggravate leukocyte-mediated tissue injury by increased adhesion, may not be as great a concern as previously suggested.
Nohé
Boris
B
Department of Anesthesiology and Intensive Care Medicine, Eberhard-Karls University Tuebingen, Germany. boris.nohe@uni-tuebingen.de
Ries
Reiner
R
Ploppa
Annette
A
Zanke
Christof
C
Eichner
Martin
M
Unertl
Klaus
K
Dieterich
Hans-Jürgen
HJ
D000368:Aged; D016063:Blood Loss, Surgical; D002448:Cell Adhesion / Q000502:physiology; D002465:Cell Movement / Q000502:physiology*; D016001:Confidence Intervals; D004730:Endothelium, Vascular / Q000166:cytology* / Q000502:physiology*; D006801:Humans; D007430:Intraoperative Care / Q000379:methods* / Q000706:statistics & numerical data; D007958:Leukocyte Count; D007962:Leukocytes / Q000502:physiology*; D008875:Middle Aged; D016017:Odds Ratio; D018709:Statistics, Nonparametric