Abstract： Objective To summarize the clinical experiences of performing extracorporeal membrane oxygenation (ECMO) on patients with heart and respiratory failure, and compare the clinical outcomes of Medtronic system and Quadrox PLS system. Methods We retrospectively analyzed the clinical data of 121 heart and respiratory failure patients who underwent ECMO treatment in Fu Wai Hospital from December 2004 to December 2009. Based on the different systems used, 121 patients were divided into two groups. In group M, there were 65 patients including 41 males and 24 females, with an age of 26.6±25.9 years; and they accepted Medtronic ECMO system treatment. In group Q, there were 56 patients including 39 males and 17 females, with an age of 32.4±23.9 years and they underwent Quadrox PLS ECMO system treatment. The evaluation of the clinical outcomes of these two different systems was based on the comparison of transmembrane pressure drop (TMPD), anticoagulation, hemolysis, plasma leakage, organ function, complication and hospital mortality between the two groups. Results Compared with group M, ECMO with Quadrox PLS system was associated with lower TMPD (at the beginning of ECMO: 15.0±6.0 mm Hg vs.28.0±5.0 mm Hg, P=0.000; 24 hours later: 16.0±5.0 mm Hg vs. 30.0±7.0 mm Hg, P=0.000) and less thrombus formation(7.1% vs.23.1%, P=0.037), less plasma leakage (0.0% vs. 50.8%, P=0.000), less hemolysis (14.3% vs. 29.2%, P=0.047). There were no significant differences between the two groups in support duration, complication rate, and hospital mortality(Pgt;0.05). Conclusion Both devices have similar effects for safe clinical application, but Quadrox PLS ECMO system has a relatively high biocompatibility with lower TMPD, less plasma leakage, and thrombus formation.
Objective To provide a ventricular assist device for patients with heart failure, Fu Wai （FW） axial blood pump was developed for partly or totally to assist the left ventricular function. Vitro hemolysis and animals tests were also employed to test the hydromechanics and hemocompatibility of the FW left ventricular assist devices developed in Fu Wai hospital. Methods Using vitro test loop, FW axial blood pump has been used to evaluate the performance of hemolysis， the pump has also been tested for hemolysis characteristic through five sheep experiments. Results At 8 400 r/min, the pump generates 5 L/min flow against 100 mm Hg, the normalized index of hemolysis (NIH) was0.17±0.06 mg/L. The plasma free hemoglobin of in vivo tests was around 30 mg/dl. Conclusion The results obtained in vitro and in vivo testing indicate an acceptable design for the blood pump, further in vivo tests will be performed before clinical use.
Interventional micro-axial flow blood pump is widely used as an effective treatment for patients with cardiogenic shock. Hemolysis and coagulation are vital concerns in the clinical application of interventional micro-axial flow pumps. This paper reviewed hemolysis and coagulation models for micro-axial flow blood pumps. Firstly, the structural characteristics of commercial interventional micro-axial flow blood pumps and issues related to clinical applications were introduced. Then the basic mechanisms of hemolysis and coagulation were used to study the factors affecting erythrocyte damage and platelet activation in interventional micro-axial flow blood pumps, focusing on the current models of hemolysis and coagulation on different scales (macroscopic, mesoscopic, and microscopic). Since models at different scales have different perspectives on the study of hemolysis and coagulation, a comprehensive analysis combined with multi-scale models is required to fully consider the influence of complex factors of interventional pumps on hemolysis and coagulation.
Red blood cells are destroyed when the shear stress in the blood pump exceeds a threshold, which in turn triggers hemolysis in the patient. The impeller design of centrifugal blood pumps significantly influences the hydraulic characteristics and hemolytic properties of these devices. Based on this premise, the present study employs a multiphase flow approach to numerically simulate centrifugal blood pumps, investigating the performance of pumps with varying numbers of blades and blade deflection angles. This analysis encompassed the examination of flow field characteristics, hydraulic performance, and hemolytic potential. Numerical results indicated that the concentration of red blood cells and elevated shear stresses primarily occurred at the impeller and volute tongue, which drastically increased the risk of hemolysis in these areas. It was found that increasing the number of blades within a certain range enhanced the hydraulic performance of the pump but also raised the potential for hemolysis. Moreover, augmenting the blade deflection angle could improve the hemolytic performance, particularly in pumps with a higher number of blades. The findings from this study can provide valuable insights for the structural improvement and performance enhancement of centrifugal blood pumps.