Human neutrophil activation and increased adhesion by various resuscitation fluids

Introduction: Activated neutrophils play a major role in secondary tissue injury following resuscitation In trauma. Hypothesis: Human neutrophil activation and adhesion vary depending on the type of resuscitation fluid used. Methods: Whole blood from ten healthy volunteers was serially diluted in polypropylene tubes with various resuscitation fluids. Neutrophil activation (intracellular oxidative burst activity with dichloroflurodn diacetate staining) and adhesion (integrin, cell surface expression of CD18) were measured with Flow cytometry (FACS). Blood was diluted with hypertonic saline (HTS) by controlling for equal sodium content as normal saline (NS). ANOVA with Bonferoni correction for multiple comparisons was used to test for significance at the p <0.05 level. Palred t test compared to baseline at the p <0.05 levelt. Results: Results are shown as percent change compared to NS as the baseline. There was a significant dose responsive increase in neutrophils oxidative burst activity all fluids except for 25% albumin and HTS. The increase was markedly higher with crystalloids and artificial colloids. Dilution - Blood/fluid 90ul/10ul 75ul/25ul SOul/SOul 25ul/7Sul Normal Saline * 100 136† 555† 1380†* Lactated Ringers * 112 154† 362† 1261†* Dextran * 99 148† 427†1726†* Hespan * 104 128† 296† 1876†* 7.5% HTS by [Na⁺] 95 92 96 108 3.5% HTS by [Na⁺] 93 93 98 103 25% Albumin 88 91 95 100 5% Albumin * 98 118 153† 223*† There was also a similar significant increase in the CD18 expression with artificial colloids (p < 0.05) but not with albumin or crystalloids. Hypertonic saline caused a decrease in CD18 expression. Conclusions: All resuscitative fluids may not be similar nor innocuous, as demonstrated by the dose response increase in neutrophil activation and adhesion. The type of resuscitative fluid and volume used may contribute to reperfusion injury in trauma patients.