Uribarri J, Prabhakar S, Kahn T
Renal Division, Mount Sinai School of Medicine, New York, USA.
Clin Nephrol. 2004 Jan;61(1):54-8. doi: 10.5414/cnp61054.
Low serum sodium is uncommon in peritoneal dialysis (PD), which is surprising in view of the important role of normal kidney function to regulate water and sodium balance.
We report 2 cases of persistent hyponatremia with balance studies in Case 1. We performed measurements of dialysate sodium and volume output over 24 hours in a group of chronic PD patients.
The low serum sodium concentration did not vary too much with overall fluid removal via dialysis in patient 1, mainly because large quantities of sodium were removed in the dialysate. In the 24-hour studies, a significant relationship was found between net daily PD sodium removal and net daily dialysate volume removed (r = 0.65). There was no relationship between net daily PD sodium removal and serum sodium concentration. There was a linear direct correlation between serum and dialysate sodium concentration (r = 0.8) as shown by others previously.
These results suggest that the main determinant of PD sodium loss is net dialysate ultrafiltration volume. Water loss via dialysis is necessarily associated with sodium loss. In order to maintain a normal serum sodium concentration salt intake must be proportional to the water loss induced by dialysis. The stimuli that allow dialysis patients to maintain this delicate balance between water and salt intake are of considerable interest but remain undetermined.
低血清钠在腹膜透析（PD）中并不常见，鉴于正常肾功能在调节水和钠平衡方面的重要作用，这一点令人惊讶。
我们报告了2例持续性低钠血症病例，病例1进行了平衡研究。我们对一组慢性PD患者进行了24小时透析液钠含量和尿量的测量。
在患者1中，低血清钠浓度与通过透析总体液体清除量的变化不大，主要是因为透析液中大量钠被清除。在24小时研究中，发现每日腹膜透析钠净清除量与每日透析液净清除量之间存在显著关系（r = 0.65）。每日腹膜透析钠净清除量与血清钠浓度之间无关系。如先前其他人所示，血清和透析液钠浓度之间存在线性直接相关性（r = 0.8）。
这些结果表明，腹膜透析钠丢失的主要决定因素是透析液净超滤量。通过透析的水分丢失必然与钠丢失相关。为了维持正常血清钠浓度，盐摄入量必须与透析引起的水分丢失成比例。使透析患者维持水和盐摄入之间这种微妙平衡的刺激因素备受关注，但仍未确定。
