Cheng Li-Tao, Wang Tao
Institute of Nephrology, First Hospital, Peking University, Beijing, China.
Perit Dial Int. 2006 Mar-Apr;26(2):218-23.
Dietary salt and fluid restriction is important in controlling fluid balance in patients on continuous ambulatory peritoneal dialysis (CAPD). However, it is often difficult to monitor patients' dietary total sodium intake (TSI). Usually, total sodium removal (TSR), the sum of urinary sodium removal (USR) and dialysate sodium removal (DSR), is suggested to represent TSI. In the present study, we investigated the reliability of using TSR as a surrogate to TSI in CAPD patients.
40 clinically stable CAPD patients were closely followed for 3 months. Their TSI, USR, DSR, and fluid status were measured twice: at baseline and at the end of this study respectively. Fluid status was evaluated by bioimpedance analysis. Patients with increased sodium intake (group ISI) or decreased sodium intake (group DSI) (both >0.5 g/day or >21.74 mmol/day elemental sodium) were included in this study.
There were 15 patients in group ISI and 9 patients in group DSI. During the follow-up, although TSI increased in group ISI and decreased in group DSI (p < 0.05), there were no significant changes in USR, DSR, or TSR in either group. No relationship was found between TSI and TSR. Changes in weight, blood pressure, urine volume, ultra-filtration, and small solute removal (Kt/V and creatinine clearance) were not statistically significant between the two groups. Fluid status deteriorated in group ISI and improved in group DSI (p < 0.05).
Our study suggests that changes in total sodium intake do not lead to proportionate changes in total sodium removal in CAPD patients. Therefore, TSR (the sum of USR and DSR) should be used cautiously to monitor TSI in this patient population.
饮食中限制盐和液体摄入对于控制持续性非卧床腹膜透析（CAPD）患者的液体平衡很重要。然而，监测患者饮食中的总钠摄入量（TSI）往往很困难。通常，建议用总钠清除量（TSR），即尿钠清除量（USR）和透析液钠清除量（DSR）之和，来代表TSI。在本研究中，我们调查了在CAPD患者中使用TSR作为TSI替代指标的可靠性。
40例临床稳定的CAPD患者被密切随访3个月。分别在基线和研究结束时测量他们的TSI、USR、DSR和液体状态两次。通过生物电阻抗分析评估液体状态。本研究纳入了钠摄入量增加（ISI组）或钠摄入量减少（DSI组）（两者均>0.5 g/天或>21.74 mmol/天元素钠）的患者。
ISI组有15例患者，DSI组有9例患者。在随访期间，尽管ISI组的TSI增加而DSI组的TSI减少（p<0.05），但两组的USR、DSR或TSR均无显著变化。未发现TSI与TSR之间存在关联。两组之间体重、血压、尿量、超滤和小分子溶质清除率（Kt/V和肌酐清除率）的变化无统计学意义。ISI组的液体状态恶化，DSI组的液体状态改善（p<0.05）。
我们的研究表明，CAPD患者总钠摄入量的变化不会导致总钠清除量成比例变化。因此，在该患者群体中，应谨慎使用TSR（USR和DSR之和）来监测TSI。
