La Milia Vincenzo, Di Filippo Salvatore, Crepaldi Monica, Andrulli Simeone, Del Vecchio Lucia, Scaravilli Pietro, Virga Giovambattista, Locatelli Francesco
Department of Nephrology and Dialysis, A Manzoni Hospital, Lecco, Italy.
Nephrol Dial Transplant. 2004 Jul;19(7):1849-55. doi: 10.1093/ndt/gfh223. Epub 2004 Apr 6.
Sodium removal (NaR) may have a major impact on the survival of peritoneal dialysis patients. The dialysate/plasma sodium concentration ratio (D/P(Na)) is an indirect index of transcellular water transport by aquaporin channels, and thus of ultrafiltration. Sodium concentration can be assessed by means of flame photometry (F), and direct (D-ISE) or indirect ion-selective electrodes (I-ISE), but these methods have different properties. I-ISE is being used increasingly in clinical laboratories. The aim of this study was to evaluate NaR and D/P(Na) using the three different measurement methods.
We performed peritoneal equilibration tests (PETs) in 44 peritoneal dialysis patients and calculated the NaR. We also calculated D/P(Na) during the test; plasma and dialysate sodium concentrations were measured by F, D-ISE and I-ISE.
NaR was lower (P<0.001) with D-ISE (69+/-29 mmol) than with F (81+/-29 mmol) or I-ISE (79+/-28 mmol). D/P(Na) was also lower at baseline (0.92+/-0.02 vs 0.95+/-0.02 and 0.95+/-0.02; P<0.001), after 60 min (0.87+/-0.03 vs 0.90+/-0.03 and 0.90+/-0.03; P<0.001) and at the end of PET (0.88+/-0.04 vs 0.92+/-0.04 and 0.92+/-0.04; P<0.001) when measured by D-ISE in comparison with F and I-ISE, respectively.
NaR and D/P(Na) were lower when measured by the D-ISE method compared with the F and I-ISE methods. NaR and D/P(Na) were similar when measured by F or I-ISE. I-ISE can be used reliably in the evaluation of NaR and D/P(Na) in everyday clinical practice of peritoneal dialysis.
钠清除（NaR）可能对腹膜透析患者的生存产生重大影响。透析液/血浆钠浓度比（D/P(Na)）是水通道蛋白通道介导的跨细胞水转运以及超滤的间接指标。钠浓度可通过火焰光度法（F）、直接离子选择性电极法（D-ISE）或间接离子选择性电极法（I-ISE）进行评估，但这些方法具有不同特性。I-ISE在临床实验室中的使用越来越广泛。本研究的目的是使用三种不同测量方法评估NaR和D/P(Na)。
我们对44例腹膜透析患者进行了腹膜平衡试验（PETs）并计算NaR。我们还在试验期间计算D/P(Na)；通过F、D-ISE和I-ISE测量血浆和透析液钠浓度。
与F法（81±29 mmol）或I-ISE法（79±28 mmol）相比，D-ISE法测得的NaR更低（P<0.001）（69±29 mmol）。与F法和I-ISE法相比，D-ISE法测量时，基线时D/P(Na)也更低（0.92±0.02 vs 0.95±0.02和0.95±0.02；P<0.001），60分钟后（0.87±0.03 vs 0.90±0.03和0.90±0.03；P<0.001）以及PET结束时（0.88±0.04 vs 0.92±0.04和0.92±0.04；P<0.001）。
与F法和I-ISE法相比，D-ISE法测得的NaR和D/P(Na)更低。F法或I-ISE法测量时，NaR和D/P(Na)相似。在腹膜透析的日常临床实践中，I-ISE可可靠地用于评估NaR和D/P(Na)。
