Artificial organs
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Clinical Trial
Favorable effect of new artificial liver support on survival of patients with fulminant hepatic failure.
The two most serious symptoms of fulminant hepatic failure are bleeding and hepatic coma. To overcome these problems, we developed an artificial liver support system comprising a combination of plasma exchange and hemodiafiltration using a high performance membrane. We treated 67 patients with fulminant hepatic failure. ⋯ In addition, 7 of 15 HB virus carriers (46.7%) who developed fulminant hepatitis and 11 of 29 patients (37.9%) with fulminant hepatitis caused by non-A, non-B hepatitis viruses survived. The overall survival rate was 37 of 67 patients (55.2%). Our artificial liver support system allows as high a survival rate as liver transplantation.
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A simple analysis and graphic result are presented for characterizing the dependence of CO2 exchange on the sweep gas (ventilating gas) flowrate in artificial lungs. The analysis requires no knowledge of the device-specific mass transfer characteristics of an artificial lung, nor does it require detailed mathematical modeling or computer simulation. ⋯ Achieving a CO2 exchange rate within 85% of maximal (for a given oxygenator and blood-side conditions) requires a sweep gas flowrate of no less than approximately 50 times the nominal CO2 exchange rate. When the sweep gas flowrate is less than 20 times the CO2 exchange rate, CO2 exchange is highly gas flow dependent and less than one-half the maximal possible rate.
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Although the natural history of acute myocarditis leads to complete recovery in the majority of patients, rapid and irreversible cardiac decompensation resulting in death is known to occur. One possible therapy to improve the poor prognosis of this patient group may be the implantation of circulatory support systems that allow myocardial recovery or bridging to heart transplantation. Therapeutic protocols have been suggested, but clinical experiences in this area are few. ⋯ In both cases, HTXs were performed without any complication. The postoperative course was uneventful. The results of mechanical circulatory support in patients with acute fulminant myocarditis are encouraging and justify the resources.
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Comparative Study Clinical Trial Controlled Clinical Trial
Changes in platelet, granulocyte, and complement activation during cardiopulmonary bypass using heparin-coated equipment.
The effects of heparin-coated cardiopulmonary bypass (CPB) systems on platelet, granulocyte, and complement activation were investigated during cardiopulmonary bypass. Thirty patients underwent coronary artery bypass surgery with a heparin-coated (Carmeda Bio-Active Surface, CBAS, Medtronic, U. S. ⋯ The heparin-coated oxygenator and uncoated CPB circuit reduced complement activation but demonstrated no significant effects on the platelet and granulocyte systems. However, the heparin-coated CPB circuit (with all components making blood contact) reduced platelet, granulocyte, and complement activation and significantly reduced postoperative blood loss. Therefore, heparin coating of CPB systems improves biocompatibility.
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We have studied the fluctuations of an artificial circulation for the analysis of the physiological aspects; however, the conventionally used fast Fourier transform (FFT) method cannot separate harmonic oscillations, such as respiratory and Mayer waves, from the 1/f fluctuation, which has been though to represent underlying fractal dynamics. Fractal structure was shown in the strange attractor with chaotic dynamics, which is thought to be a flexible and intelligent system. In this study, the coarse-graining spectral analyzing (CGSA) method was utilized to quantitatively evaluate the proportion of the 1/f fluctuation in the total power in the frequency domain and to analyze artificial circulation in the whole system. ⋯ Fractal percentages of the arterial blood pressure were 85.8 +/- 10.7% and 82.0 +/- 7.3% with natural and artificial circulation, respectively (not significant [NS]). 1/f fluctuation showed the characteristics of being fractal in a time series. The fractal structure showed robustness and error resistance in nonlinear dynamics. Therefore, our results suggest that the circulatory regulatory system of the artificial heart may have desirable characteristics such as error resistance.