Artificial organs
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Studies on pulsatile and nonpulsatile perfusion have long been performed. However, investigators have not reached a conclusion on which is more effective. In the present study, pulsatile cardiopulmonary bypass (CPB) was investigated in terms of the effects on cytokines, endothelin, catecholamine, and pulmonary and renal functions. ⋯ Both epinephrine and norepinephrine were significantly lower in the pulsatile group. The respiratory index was significantly higher in the pulsatile group. In the present study, inhibitory effects on cytokine activity, edema in pulmonary alveoli, and endothelial damage were shown in addition to the favorable effects on catecholamine level, renal function, and peripheral circulation that have already been documented.
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Clinical Trial Controlled Clinical Trial
Heparin influences human platelet behavior in cardiac surgery with or without cardiopulmonary bypass.
The objective was to investigate whether the platelet dysfunction in cardiac surgery is caused by hemodilution or by shear stress due to cardiopulmonary bypass (CPB). Platelet count and function were prospectively analyzed in two groups of patients undergoing cardiac surgery either with or without CPB (n = 40). In the first study (n = 20; 10 patients with and 10 without CPB), platelet counts were assessed at seven time points. ⋯ The reduction in platelet count is similar with or without cardiopulmonary bypass and is due to pure hemodilution. Platelet function reduces significantly after heparin administration. Hemodilution and predominantly heparin are the causes of platelet dysfunction after cardiac surgery.
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The Cleveland Clinic Foundation's (CCF) cardiopulmonary bypass/extracorporeal membrane oxygenation (CPB/ECMO) system capabilities were tested in a hypothermia trauma management feasibility study in a porcine animal model at the Uniformed Services University of the Health Sciences (USUHS, Bethesda, MD, U. S. A.). ⋯ Neurological findings, organ dysfunction, and complication rates also were no different from previous studies using standard equipment. Successful survival results demonstrated that the CCF CPB/ECMO system could be used to induce a period of profound hypothermic arrest for the repair of lethal traumatic injuries. The logistical advantages of this system make it an attractive choice for use in austere settings and during transport.
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Centrifugal pump performance characteristics are vital in determining the ability of a prototype left ventricular assist device (LVAD) to meet the physiological circulation requirements of the cardiovascular system. These characteristics influence the static hydraulic forces encountered by the pump impeller, which determine the required load stiffness of suspension type bearings to minimize impeller touchdown. Performance investigations were conducted on an LVAD design while characterizing the impeller static hydraulic forces of various impeller/volute configurations. ⋯ The reduction of left atrial pressure (25 to 8 mm Hg) indicated the alleviation of pulmonary congestion. The ability for the LVAD to support circulation in a left heart failure environment was successfully demonstrated in the mock circulation loop. The impeller hydraulic force characteristics attained will aid the bearing designer to select the best volute and impeller configuration to minimize impeller touchdown in magnetic, hydrodynamic or mechanical type bearing applications.
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Sensory supported electrical stimulation of the peroneal nerve during treadmill walking is proposed as a gait-training modality in incomplete spinal cord injury (SCI) patients. A multisensor device provides information on the tilt of the shank during gait. ⋯ Simultaneously, swing-phase estimation serves as a reference to determine the required motor augmentation support. Both approaches, as well as triggering using intensity control of the functional electrical stimulation were applied on a healthy person and on an incomplete C4-5 SCI patient.