Polaschegg H D, Wojke R
Research & Development Medical Systems Division, Fresenius AG, Bad Homburg, Germany.
Int J Artif Organs. 1993 Jul;16(7):505-9.
Single-needle (SN) dialysis employs tidal blood flow at the point of vascular access. The simplest SN systems convert this tidal flow to a pulsatile flow in the dialyser. It has been assumed that constant flow through the dialyser is necessary for optimal efficiency. Therefore SN blood circuits are designed to smooth the pulsatile flow in the dialyser to a relatively constant flow. This increase the complexity and cost of the SN system. In order to test the hypothesis that pulsatile flow results in lower clearances than constant flow, we performed measurements of clearance in vitro using pulsatile blood flow at time-averaged rates of 50-250 ml/min and tidal volumes 200-100 ml/min. These were compared with clearances using constant blood flow at the same rates. At all flow rates and at tidal volumes up to 50 ml, the clearance measurements obtained during pulsatile flow were identical to those obtained during constant flow.
单针（SN）透析在血管通路处采用潮汐式血流。最简单的SN系统会将这种潮汐流转换为透析器中的脉动流。一直以来人们认为，为实现最佳效率，透析器中保持恒定血流是必要的。因此，SN血液回路被设计成将透析器中的脉动流平滑为相对恒定的血流。这增加了SN系统的复杂性和成本。为了检验脉动流导致的清除率低于恒定流这一假设，我们在体外进行了测量，使用的脉动血流的时间平均速率为50 - 250毫升/分钟，潮气量为200 - 100毫升/分钟。并将这些结果与相同速率下恒定血流的清除率进行了比较。在所有流速以及潮气量高达50毫升时，脉动流期间获得的清除率测量结果与恒定流期间获得的结果相同。
