In vitro hemolysis testing is commonly used to determine hemocompatibility of ExtraCorporeal Membrane Oxygenation (ECMO). However, poor reproducibility remains a challenging problem, due to several unidentified influencing factors. The present study investigated potential factors, such as flow rates, the use of anticoagulants, and gender of blood donors, which could play a role in hemolysis. Fresh human whole blood was anticoagulated with either citrate (n = 6) or heparin (n = 12; 6 female and 6 male blood donors). Blood was then circulated for 360 min at 4 L/min or 1.5 L/min. Regardless of flow rate conditions, hemolysis remained unchanged over time in citrated blood, but significantly increased after 240 min circulation in heparinized blood (p ≤ 0.01). The ratio of the normalized index of hemolysis (NIH) of heparinized blood to citrated blood was 11.7-fold higher at 4 L/min and 16.5–fold higher at 1.5 L/min. The difference in hemolysis between 1.5 L/min and 4 L/min concurred with findings of previous literature. In addition, the ratio of NIH of male heparinized blood to female was 1.7-fold higher at 4 L/min and 2.2-fold higher at 1.5 L/min. Our preliminary results suggested that the choice of anticoagulant and blood donor gender could be critical factors in hemolysis studies, and should be taken into account to improve testing reliability during ECMO.

Extracorporeal membrane oxygenation (ECMO), a critical life-sustaining tool, faces significant challenges for the maintenance of normal haemostasis due to the large volume of circulating blood continuously in contact with artificial...

Background: Aggressive fluid or blood component transfusion for severe hemorrhagic shock may restore macrocirculatory parameters, but not always improve microcirculatory perfusion and tissue oxygen delivery. We established an ovine model of hemorrhagic shock to systematically assess tissue oxygen delivery and repayment of oxygen debt; appropriate outcomes to guide Patient Blood Management. Methods: Female Dorset-cross sheep were anesthetized, intubated, and subjected to comprehensive macrohemodynamic, regional tissue oxygen saturation (StO 2 ), sublingual capillary imaging, and arterial lactate monitoring confirmed by invasive organ-specific microvascular perfusion, oxygen pressure, and lactate/pyruvate levels in brain, kidney, liver, and skeletal muscle. Shock was induced by stepwise withdrawal of venous blood until MAP was 30 mm Hg, mixed venous oxygen saturation (SvO 2 ) < 60%, and arterial lactate >4 mM. Resuscitation with PlasmaLyte1 was dosed to achieve MAP > 65 mm Hg. Results: Hemorrhage impacted primary outcomes between baseline and development of shock: MAP 89 AE 5 to 31AE 5 mm Hg (P < 0.01), SvO 2 70 AE 7 to 23 AE 8% (P < 0.05), cerebral regional tissue StO 2 77 AE 11 to 65 AE 9% (P < 0.01), peripheral muscle StO 2 66 AE 8 to 16 AE 9% (P < 0.01), arterial lactate 1.5 AE 1.0 to 5.1 AE 0.8 mM (P < 0.01), and base excess 1.1 AE 2.2 to À3.6 AE 1.7 mM (P < 0.05). Invasive organ-specific monitoring confirmed reduced tissue oxygen delivery; oxygen tension decreased and lactate increased in all tissues, but moderately in brain. Blood volume replacement with PlasmaLyte1 improved primary outcome measures toward baseline, confirmed by organ-specific measures, despite hemoglobin reduced from baseline 10.8 AE 1.2 to 5.9 AE 1.1 g/dL post-resuscitation (P < 0.01). Conclusion: Non-invasive measures of tissue oxygen delivery and oxygen debt repayment are suitable outcomes to inform Patient Blood Management of hemorrhagic shock, translatable for pre-clinical assessment of novel resuscitation strategies.