Ex vivo analysis of packed red blood cell hemolysis during transfusion by pneumatic pressure bags

Objective: to investigate markers of red cell hemolysis in stored blood infused by pneumatic pressure bags under a pressure of 300 mmHg. Methods: ex vivo experimental study simulating the clinical practice of massive packed red blood cell transfusion by pressure bags. The experiments were carried out under controlled conditions in a laboratory and the levels of hemolysis markers [total hemoglobin (g/dL), hematocrit (%), free hemoglobin (g/dL), potassium (mmol/L), lactate dehydrogenase (U/L) and degree of hemolysis (%)] were assessed before device inflation (control), and immediately, one and two hours after inflation under a pressure of 300 mmHg. Data were analyzed with parametric and non-parametric tests and the significance level was set at 5%. Results: the analysis showed increased free hemoglobin level (p=0.004) and hemolysis ratio (p=0.004) immediately after compression, increased lactate dehydrogenase one hour after compression (p=0.020), and decreased total hemoglobin (p=0.002) two hours after compression, without significant variations in potassium or hematocrit levels. Conclusion: the use of pressure bags for infusion of red blood cells caused alterations in hemolysis markers mainly after two hours of compression.