Abstract
Single needle dialysis (SND) was developed in the 1960's. Although this method has appreciable advantages over the double needle dialysis (DND) used so far, it has not reached routine clinical application. Moreover, there has been little experimental research on the increase of dialysis efficiency in SND in Japan. The aim of this study, was therefore, to investigate the effects of 4 parameters on dialysis efficiency in SND. These parameters were shunt flow, extracorporeal circulation flow, blood return pressure, and blood return time.
Material and Methods: A water tank filled with a 100mg/ml urea solution was used as the model of intracorporeal circulation, and was connected with the SND system. After 30 minutes simulation circulation, experiments were performed under various conditions of the 4 parameters, and the results were analyzed to find the optimal conditions for maximum dialysis efficiency in SND.
The results were as follows:
With increase in shunt flow from 100 to 300ml/min, the urea extraction rate was significantly increased. Under a shunt flow of less than 200ml/min, the urea extraction rate was not affected by the extracorporeal circulation flow, whereas the rate increased with increase in the extracorporeal circulation flow under a shunt flow of more than 300ml/min, Blood return time did not significantly affect the urea extraction rate irrespective of the shunt flow. The urea extraction rate went up together with blood return pressure. At a low shunt flow (below 200ml/min) there was no significant difference between DND and SND. However there was a significant difference between DND and SND when the shunt flow was over 300ml/min.
