Extracorporeal life support (ECLS) is a treatment modality that provides prolonged blood circulation, gas exchange and can partially support or fully substitute functions of heart and lungs in patients with severe but potentially reversible cardiopulmonary failure refractory to conventional therapy. Due to high-volume bypass, the extracorporeal flow is interacting with native cardiac output. The pathophysiology of circulation and ECLS support reveals significant effects on arterial pressure waveforms, cardiac hemodynamics, and myocardial perfusion. Moreover, it is still subject of research, whether increasing stroke work caused by the extracorporeal flow is accompanied by adequate myocardial oxygen supply. The left ventricular (LV) pressure-volume mechanics are reflecting perfusion and loading conditions and these changes are dependent on the degree of the extracorporeal blood flow. By increasing the afterload, artificial circulation puts higher demands on heart work with increasing myocardial oxygen consumption. Further, this can lead to LV distention, pulmonary edema, and progression of heart failure. Multiple methods of LV decompression (atrial septostomy, active venting, intra-aortic balloon pump, pulsatility of flow) have been suggested to relieve LV overload but the main risk factors still remain unclear. In this context, it has been recommended to keep the rate of circulatory support as low as possible. Also, utilization of detailed hemodynamic monitoring has been suggested in order to avoid possible harm from excessive extracorporeal flow., Pavel Hála, Otomar Kittnar., and Obsahuje bibliografii
In the present study, a method has been employed for hepatocyte immobilization in agarose threads which allows for cell perfusion. The rat hepatocytes are isolated from the liver. A 1.8 % low-gelling agarose solution is prepared in warm Krebs-Henseleit solution. The agarose solution is mixed 1:1 with the hepatocytes and the cells are immobilized in agarose threads by extruding the agarose-cell mixture through cooled Chemfluor teflon (TFE) tubing. Light and electron microscopy studies indicated the integrity of the hepatocytes in the gel matrix. This system allows for liver cell perfusion and viability studies to be carried out non-invasively on the cells and provides data that are comparable to those obtained with a perfused isolated liver. Immobilized hepatocytes are an in vitro system worthy of further evaluation which may be useful in the studies of liver cell metabolism and the response of the liver to foreign chemicals.