Microfluidics-based study on the damage pattern of red blood cells and VWF / 国际生物医学工程杂志

Objective:To investigate the effects of shear stress magnitude and exposure time on the damage of blood component erythrocytes and von willebrand factor (VWF) based on microfluidic technology.Methods:A blood shear platform was built based on a microfluidic chip, samples were prepared under different shear stress magnitudes and exposure time lengths, free hemoglobin assay experiments were performed on blood samples, the hemolysis indices of different samples were measured, and the relative molecular masses of different samples of VWF were analyzed by immunoblotting and chemiluminescence imaging.Results:The quantitative relationships between the hemolysis index and the degradation rate of high relative molecular mass VWF with shear stress and exposure time followed the power function model well.Conclusions:The microfluidic experimental platform has the advantages of a precise and controllable internal microenvironment and easy and rapid detection, which can be used for the quantitative study of blood damage patterns.

VWF Damage Based on Novel Maglev Taylor-Couette Blood-Shearing Circulation Platform / 医用生物力学

Objective To study von Willebrand factor(VWF) damage based on a novel Maglev Taylor-Couette blood-shearing device. Methods The magnetic levitation (maglev) Taylor-Couette blood-shearing device was designed, and the blood-shearing platform was built. Fresh porcine blood was tested in circulation loop for 1 hour at laminar flow state. VWF damage was assessed by analyzing sample through Western blot and enzyme-linked immunosorbent assay. Results With the increase of exposure time and shear stress, a large number of high molecular weight VWF multimers were degraded into low molecular weight VWF. The maximum rate of degradation was 569%. When the shear stress increased from 18 Pa to 55 Pa, the ratio of VWF-Rco to VWF-Ag decreased from 45.7% to 32.8%. ConclusionsCompared with initial sample, the VWF damage was mainly manifested by the decrease of high molecular weight VWF and the decrease of VWF activity, and VWF-Ag did not change significantly. The novel maglev Taylor-Couette blood-shearing device can quantitatively control the flow parameters (exposure time and shear stress), and be used for blood damage research in vitro, thus providing references for the design and optimization of extracorporeal membrane oxygenation and blood pump.

Evaluation on Mechanical Damage of vWF Induced by Shear Stress in BPX-80 Centrifugal Blood Pump / 医用生物力学

Objective To evaluate the damage of von Willebrand factor (vWF) induced by shear stress in BPX-80 centrifugal blood pump, and determine whether it can be used as a reference pump for vWF damage research. Methods An in vitro hemolysis test platform was established according to the ASTM standards. The BPX-80 centrifugal blood pump was tested for 8 hours by using fresh porcine blood. The hemolysis level and vWF damage of hourly blood samples were then evaluated and compared with the static control group. ResultsThe hemolysis index of BPX-80 was stable and low during the test; vWF polymer with high molecular weight had a small amount of degradation, and showed no significant difference compared with the static control group; there was no significant change in the concentration of vWF antigen, which was basically consistent with the trend of the static control group. Conclusions BPX-80 centrifugal blood pump has good blood compatibility and can be used as the reference pump for vWF damage and hemolysis evaluation, thereby providing guidance for the design and optimization of new blood pumps.

Exploration of New Pharmacy Management Model Based on VMI Model under New Medical Reform / 中国药房

OBJECTIVE:To investigate the new management model of the hospital pharmacy established by application of vender managed inventory (VMI) model. METHODS:Concerned about the implementation of VMI model,its effects and prob-lems,new management model of hospital pharmacy were described after the hospital cooperated with two suppliers. The hospital is mainly in charge of the management and application of pharmaceutical staff and equipment,drug capital flow,and the selection and optimization of drug use list;focus on the training of pharmaceutical talents;improve drug quality management,pharmaceuti-cal administration,pharmaceutical care and rational drug use. Two suppliers are mainly in charge of drug logistics,and the alloca-tion of servicer,software and hardware(as automatic medicine dispensing machine);share logistic cost of supply chain. Drug in-formation flow was established by both hospital and supplier. RESULTS:After cooperation,pharmaceutical staff,related equip-ment and inventory cost(floating capital decreased by 10 million yuan each month)were decreased,and the efficiency of distribu-tion improved;the error rate of drug dispensing in outpatient pharmacy were decreased (decreasing from 0.39‰ to 0.12‰) after the establishment of automatic pharmacy. The establishment of early warning system for abnormal patients flowrate in pharmacy window shortened the time of getting medicine,and improved service level and satisfactory degree of patients (increasing from 84.91% to 93.62%). CONCLUSIONS:New management model of hospital pharmacy based on VMI model provides reference for public hospital reform and hospital-enterprise cooperation under New Medical Reform.