Influence of hemoultrafiltration and hemodialysis on endothelin.

To study the mechanism of plasma endothelin (pET) increment in chronic renal failure (CRF) patients, we investigated 20 CRF cases given hemoultrafiltration for 90 min followed by hemodialysis and 12 given hemodialysis only to examine the effect on ET. The results revealed that 90-min ultrafiltration with 2 500ml fluid extraction significantly decreased plasma ET (1 132 +/- 793--753 +/- 702 pg/ml, P less than 0.05), while hemodialysis without water extraction for the same period of time resulted in no significant change (1 195 +/- 891--1 011 +/- 654pg/ml, P greater than 0.05). BUN in the ultrafiltration group showed no marked changes (102 +/- 11.4--83.5 +/- 119 mg/dl), but the hemodialysis group presented a significant decrease (97 +/- 12--63 +/- 7 mg/dl, P less than 0.05), showing that the ET fall had no significant relevance to the metabolic products extracted. In 120 min following hemodialysis, ET levels in both groups decreased by different amounts. MAP decreased in both groups throughout the procedure period. Therefore, it is suggested that decreased extracellular volume via ultrafiltration can lead to lowering of ET levels, showing that extracellular volume may influence the ET level.