Epsom and St Helier University Hospitals NHS Trust.
Nephrol Dial Transplant. 2013 Aug;28(8):2181-6. doi: 10.1093/ndt/gft081. Epub 2013 Jun 5.
Plasma sodium is increased following each meal containing salt. There is an increasing interest in the effects of plasma sodium concentration, and it has been suggested that it may have direct effects on blood pressure (BP) and possibly influences endothelial function. Experimental increases of plasma sodium concentration rapidly raise BP even when extracellular volume falls.
Ten patients with end-stage renal failure established on haemodialysis were studied during the first 2 h of dialysis without fluid removal during this period. They were randomized to receive haemodialysis with (i) dialysate sodium concentration prescribed to 135 mmol/L and (ii) 145 mmol/L in random order in a prospective, single-blinded crossover study. BP measurements and blood samples were taken every 30 min.
Pre-dialysis sitting BP was 137/76 ± 7/3 mmHg. Lower dialysate sodium concentration (135 mmol/L) reduced plasma sodium concentration [139.49 ± 0.67 to 135.94 ± 0.52 mmol/L (P < 0.001)], whereas plasma sodium concentration was not altered by higher dialysate sodium (145 mmol/L) (140.17 ± 0.66 mmol/L at baseline to 140.72 ± 0.43 mmol/L at 120 min). Systolic BP was lower with dialysate sodium concentration 135 mmol/L [area under the curve (AUC) 15823.50 ± 777.15 (mmHg)min] compared with 145 mmol/L [AUC 17018.20 ± 1102.17 (mmHg)min], mean difference 1194.70 ± 488.41 (mmHg)min, P < 0.05. There was a significant positive relationship between change in plasma sodium concentration and change in systolic BP. This direct relationship suggests that a fall of 1 mmol/L in plasma sodium concentration would be associated with a 1.7 mmHg reduction in systolic BP (P < 0.05).
The potential mechanism for the increase in BP seen with salt intake may be through small but significant changes in plasma sodium concentration.
摄入含盐分的食物后，血浆钠浓度会升高。人们对血浆钠浓度的影响越来越感兴趣，有人认为它可能对血压（BP）有直接影响，并可能影响内皮功能。实验性地升高血浆钠浓度会迅速升高血压，即使细胞外液容量下降也是如此。
10 名终末期肾衰竭患者在透析的前 2 小时内接受研究，在此期间不进行液体清除。他们被随机分为两组，接受透析液钠浓度分别为 135mmol/L（i）和 145mmol/L（ii）的治疗，采用前瞻性、单盲交叉研究。每 30 分钟测量一次血压和采集血液样本。
透析前坐姿血压为 137/76±7/3mmHg。较低的透析液钠浓度（135mmol/L）降低了血浆钠浓度[139.49±0.67 至 135.94±0.52mmol/L（P<0.001）]，而较高的透析液钠（145mmol/L）并没有改变血浆钠浓度[140.17±0.66mmol/L 至 140.72±0.43mmol/L（P<0.001）]。透析液钠浓度为 135mmol/L 时收缩压较低[曲线下面积（AUC）15823.50±777.15（mmHg）min]，而透析液钠浓度为 145mmol/L 时收缩压较高[AUC 17018.20±1102.17（mmHg）min]，平均差值 1194.70±488.41（mmHg）min，P<0.05。血浆钠浓度的变化与收缩压的变化之间存在显著的正相关关系。这种直接关系表明，血浆钠浓度下降 1mmol/L，收缩压将下降 1.7mmHg（P<0.05）。
摄入盐后血压升高的潜在机制可能是血浆钠浓度的微小但显著变化。
