Purpose: To determine the degree of neutrophil activation caused by hemorrhagic shock and resuscitation.
Methods: Awake swine underwent 15-minute 40% blood volume hemorrhage, and a 1-hour shock period, followed by resuscitation with: group I, lactated Ringer's solution (LR); group II, shed blood; and group III, 7.5% hypertonic saline (HTS). Group IV underwent sham hemorrhage and LR infusion. Neutrophil activation was measured in whole blood using flow cytometry to detect intracellular superoxide burst activity.
Results: Neutrophil activation increased significantly immediately after hemorrhage, but it was greatest after resuscitation with LR (group I, 273 vs. 102%; p < 0.05). Animals that received shed blood (group II) and HTS (group III) had neutrophil activity return to baseline state after resuscitation. Group IV animals had an increase in neutrophil activation (259 vs. 129%; p < 0.05).
Conclusion: Neutrophil activation occurring after LR resuscitation and LR infusion without hemorrhage, but not after resuscitation with shed blood or HTS, suggests that the neutrophil activation may be caused by LR and not by reperfusion.