Artificial organs
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Randomized Controlled Trial Comparative Study Clinical Trial
Maintenance of blood heparin concentration rather than activated clotting time better preserves the coagulation system in hypothermic cardiopulmonary bypass.
In cardiopulmonary bypass (CPB), despite heparin regimens in which the activated clotting time (ACT) is kept at more than 400 s, there is biochemical evidence of thrombin generation indicating activation of the coagulation system and increased fibrinolytic activity. Therefore, to reduce the coagulant activation has been one of the main issues in the improvement of CPB. The purpose of this study was to compare the heparin concentration with the ACT and to evaluate the effect of keeping higher heparin concentration on the coagulation and fibrinolytic systems during hypothermic CPB, employing moderate hypothermia (MHT) or deep hypothermic circulatory arrest (DHT). ⋯ Furthermore, maintenance of the higher heparin concentration during hypothermic CPB may suppress the activation of the coagulation system via thrombin inhibition. That effect was more remarkable in deep hypothermic CPB. Therefore, we believe that anticoagulation management during hypothermic CPB should be based on the maintenance of the higher blood heparin concentration.
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Comparative Study
Pressure drop, shear stress, and activation of leukocytes during cardiopulmonary bypass: a comparison between hollow fiber and flat sheet membrane oxygenators.
The membrane oxygenator is known to be superior to the bubble oxygenator, but little information is available about the difference between the hollow fiber and flat sheet membrane oxygenators with regard to pressure drop, shear stress, and leukocyte activation. In this study, we compared these 2 types of membrane oxygenators in patients undergoing cardiopulmonary bypass (CPB) surgery with special focus on leukocyte activation and pressure drop across the oxygenators. Plasma concentration of elastase, a marker indicating leukocyte activation, increased to 593+/-68% in the flat sheet oxygenator group versus 197+/-42% in the hollow fiber oxygenator group (p<0.01) at the end of CPB compared to their respective baseline concentrations before CPB. ⋯ However, this positive correlation existed in the flat sheet oxygenator but not in the hollow fiber oxygenator. Clinically, both membrane oxygenators have satisfactory performance in O2 and CO2 transfer. These results suggest that a higher pressure drop across the flat sheet oxygenator is associated with more pronounced activation of leukocytes in patients undergoing cardiopulmonary bypass.
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The hypothesis that regions of low blood velocity in a membrane oxygenator, as predicted by computational fluid dynamics (CFD), would correspond with regions of clinical thrombotic deposition was investigated. Twenty heparin-coated oxygenators were sectioned following use in adult extracorporeal membrane oxygenation. The activated clotting time (ACT) was maintained at approximately 180 s via heparin infusion throughout the support period. ⋯ CFD results demonstrated that low velocity regions qualitatively matched regions with a high incidence of thrombotic deposition. Thrombotic deposition was also correlated to longer perfusion periods. This technique of coupling clinical data and CFD offers the potential to relate flow characteristics to thrombotic deposition and represents a potentially powerful new methodology for the optimization of oxygenator flow-related biocompatibility.
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Randomized Controlled Trial Comparative Study Clinical Trial
Effects of Duraflo II heparin-coated cardiopulmonary bypass circuits on the coagulation system, endothelial damage, and cytokine release in patients with cardiac operation employing aprotinin and steroids.
The effects of Duraflo II heparin coated cardiopulmonary bypass circuits, low-dose aprotinin, and steroids on the coagulation system, endothelial damage, and cytokine release were evaluated by comparing those treated with low-dose aprotinin and steroids. Twenty-four adult patients undergoing coronary artery bypass grafting, aortic valve replacement, or valve repair surgery were randomly assigned to 2 groups: either heparin-coated (Duraflo group, n = 12) or noncoated equipment (noncoated group, n = 12) groups. In the Duraflo group, the cardiopulmonary reservoir was also coated with heparin. ⋯ Serum IL-8 was significantly higher in the control group than in the Duraflo group at 24 h after cardiopulmonary bypass (p < 0.05). No significant difference was found in serum thrombomodulin and TNF-alpha; both were within normal during the study period. These results indicate that the use of Duraflo II heparin coated equipment and a heparin-coated cardiopulmonary reservoir suppressed excess coagulation and inflammatory reaction induced by cardiopulmonary bypass.
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Randomized Controlled Trial Comparative Study Clinical Trial
Plasmapheresis with a substitution solution of human serum protein (5%) versus plasmapheresis with a substitution solution of human albumin (5%) in patients suffering from autoimmune diseases.
Therapeutic plasma exchange (TPE) has been used extensively for over 2 decades to treat a variety of autoimmune and congenital diseases and is now widely accepted. The primary objective of this study was to compare the clinical efficacy of two plasma exchange preparations, human serum protein (HSP) and human albumin (HA). Twenty-four patients in the following disease categories underwent TPE using either HSP (Biseko, 5%) or HA (5%): systemic lupus erythematosus, 8; glomerulonephritis, 8; myasthenia gravis, 2; Guillain-Barré-syndrome, 2; recurrent iritis, 1; pemphigoid, 1; uveitis, 1; and vascular retinitis, 1. ⋯ However, patients in the HSP group were older (12.3 years), were suffering from more complicated autoimmune diseases, and the number of occasions (days) on which these were reported (6 days) was less than in the HA group (11 days). One patient in the HA group died from septic-toxic circulatory collapse on Day 49 due to an infection with resistant strains of Staphylococcus aureus. Infections in other patients did not occur; all showed considerable improvement in their symptoms and completed the study in good general condition.