The impact of suctioning RBCs from a simulated operative site on mechanical fragility and hemolysis

BACKGROUND: Intraoperative cell salvage exerts shear stress upon RBCs, particularly as they are suctioned from the surgical field. Shear stress can result in overt hemolysis or it can cause sublethal injury to the suctioned RBCs. The mechanical fragility (MF) test uses shear stress to measure the extent of RBC sublethal injury. RBCs that have sustained sublethal injury are more susceptible to shear stress induced hemolysis. In this study we suctioned whole blood samples from an artificial surgical field to determine if pre-menopausal female RBCs would demonstrate greater resistance to hemolysis and less sublethal injury compared to that of males and post-menopausal females. METHODS: Ten CPD-preserved whole blood units from these 3 donor groups were obtained and samples suctioned at -150 mmHg from a simulated surgical field. The MF test was then performed and the % hemolysis calculated. In addition the MF test was serially performed on these whole blood units during the 21 days of storage. RESULTS: There were no differences in the extent of hemolysis or RBC shear stress resistance after suctioning between the 3 donor groups. During storage the pre-menopausal female RBCs demonstrated higher shear stress tolerance compared to the males or post-menopausal females at all of the time points. CONCLUSION: Although during static storage pre-menopausal female RBCs in CPD-preserved whole blood demonstrated higher shear stress tolerance, this enhanced resistance was not observed after suctioning from a simulated surgical field.