Systemic and microvascular effects of resuscitation with blood products after severe hemorrhage in rats.

BACKGROUND Severe hemorrhage is associated with the disruption of the endothelial glycocalyx (EG), a key component of the endothelium. The effects of blood components on the EG are unknown. The present study furthers our investigations into the effects of resuscitation with blood products on the skeletal muscle microcirculation of hemorrhaged rats, focusing on packed red blood cells (PRBCs) or fresh whole blood (FWB). METHODS Rats were bled 40% of total blood volume and resuscitated with 1:1 PRBC/lactated Ringer's solution (LR), 1:1 washed PRBC (wPRBC)/LR, FWB or LR only. Sham animals were subjected to all procedures except hemorrhage and resuscitation. EG thickness, blood flow, and microvascular permeability were studied using intravital microscopy. Hemodynamics and coagulation tests (rotational thromboelastometry) were performed. RESULTS After severe hemorrhage, EG and permeability were restored to sham levels in the PRBC/LR and FWB groups, but not in the wPRBC/LR or LR groups. Clotting time was longer and clot elasticity and firmness were reduced in wPRBC/LR and LR, but not in FWB or PRBC/LR groups when compared with sham. CONCLUSION Resuscitation with FWB or PRBC/LR was superior in reversing coagulopathy, restoring EG and permeability changes following hemorrhage, compared with wPRBC/LR or LR alone. As wPRBC/LR did not improve EG and permeability, these data suggest that the removal of residual plasma protein from wPRBC or resuscitation with a protein-free solution (LR) is not able to improve microcirculation and coagulation functions in this severe hemorrhage model.