Pflederer B R, Torrey C, Priester-Coary A, Lau A H, Daugirdas J T
University of Illinois College of Medicine and Pharmacy Practice, Chicago, USA.
Kidney Int. 1995 Sep;48(3):832-7. doi: 10.1038/ki.1995.358.
The Smye method has been proposed to estimate the equilibrated post-dialysis BUN based on an additional intradialytic sample obtained approximately one hour into dialysis. However, the effects of access recirculation (AR) and cardiopulmonary recirculation (CPR) on the Smye computation and the corresponding details of how blood is sampled have not been studied. We examined the accuracy of two variations of the Smye technique. In one method, the intradialytic and postdialysis blood samples were obtained at full blood flow. In the other, the samples were obtained after two minutes of slow flow, to obviate the effects of both AR and CPR. Seventeen patients undergoing high efficiency dialysis and three- to four-hour treatment times were studied, in whom substantial AR was excluded based on two-minute slow flow urea rebound measurements during and just after dialysis. In this group equilibrated Kt/V (eKt/V) values computed using the Smye-derived equilibrated postBUN estimates (full flow samples, 1.22 +/- 0.058 SEM, slow flow samples, 1.23 +/- 0.064) were similar to eKt/V calculated from the 30-minute postdialysis BUN specimen (1.23 +/- 0.049, P = NS). In eight other patients with severe AR (mean 35% +/- 4.5), the accuracy of the full flow Smye estimates was poor when the degree of AR was not constant throughout the dialysis session. Accuracy of the slow flow Smye estimates of eKt/V was unaffected by the presence of severe AR. One advantage of using the full flow Smye method, however, was that a large delta Kt/V value ( < -0.40) was highly suggestive of severe AR.(ABSTRACT TRUNCATED AT 250 WORDS)
已有人提出采用斯迈方法，根据透析约一小时后采集的额外透析中样本，来估算透析后平衡的尿素氮（BUN）。然而，通路再循环（AR）和心肺再循环（CPR）对斯迈计算的影响以及采血的相应具体细节尚未得到研究。我们检验了斯迈技术两种变体的准确性。一种方法是在全血流状态下采集透析中及透析后血样。另一种方法是在慢血流两分钟后采集样本，以消除AR和CPR的影响。对17例接受高效透析且治疗时间为三到四小时的患者进行了研究，这些患者基于透析期间及透析刚结束时两分钟慢血流尿素反弹测量结果被排除了大量AR。在该组中，使用源自斯迈的平衡后BUN估算值计算出的平衡Kt/V（eKt/V）值（全血流样本为1.22±0.058标准误，慢血流样本为1.23±0.064）与根据透析后30分钟BUN标本计算出的eKt/V值（1.23±0.049，P=无显著差异）相似。在另外8例严重AR患者（平均35%±4.5）中，若透析过程中AR程度不恒定，全血流斯迈估算值的准确性较差。慢血流斯迈估算eKt/V的准确性不受严重AR存在的影响。然而，使用全血流斯迈方法的一个优点是，较大的Kt/V差值（<-0.40）高度提示严重AR。（摘要截取自250字）
