On the Influence of Ultrapure Dialysate on Blood Pressure and Arrythmia During Daily Hemodialysis

Biocompatible membranes have many fewer biological effects on blood during dialysis, but neither subjective nor objective symptoms are better than on bio‐incompatible membranes. We speculated that small molecular impurities in conventional dialysate (conv) may offset the advantage and tested this by changing patients from regular dialysate with both cellulosic (Cell) and polysulphone (Poly) membranes to Poly membranes with ultrapure dialysate, the Aksys PHD (PHD). We followed blood pressure and pulse changes and episodes of hypotension, and arrhythmia in 23 patients during each of 4459 daily dialyses. Patients changed from Cell + conv to PHD and from Poly + conv to PHD. The purity of dialysate was checked with the limulus test with varying sensitivity. Regular dialysate failed European (57%) and USA standard (37%) in 123 samples. PHD dialysate passed twice European standard (< 0.125 EU) in all 194 samples On ultrapure dialysate, there were statistically fewer hypotensive crashes (14.4% vs., 8.9%) and episodes of irregular pulse (2.0% vs. 0.1%). Vital signs were also much more stable on ultrapure dialysate irrespective of what membrane was used:Cell to PHD Poly to PHD Cell to PolyN: 1260 2390 433 376 1260 433 Fall in BP syst 15 ± 21 9 ± 21 27 ± 18 2 ± 21 5 ± 21 27 ± 18 Fall in BP diast 5 ± 13 2 ± 12 12 ± 9 − 1 ± 10 5 ± 13 12 ± 9 Post PR 86 ± 15 82 ± 16 78 ± 13 72 ± 11 86 ± 15 78 ± 13 Tachycardia >   90/min  + 7% − 2.6%  + 15%  + 3%  + 7%  + 15% All p < 0.0001.These observations confirm that by themselves, a biocompatible membranes confers no clinical advantage but when used with ultrapure dialysate, patients benefit greatly. Biocompatible dialysis needs both a biocompatible membrane and ultrapure dialysate.