目的 控制饮食钠的摄入对持续不卧床腹膜透析（ CAPD）患者体液平衡有着重要的作用。由于直接测定患者的钠摄入有一定困难，一般通过测定钠清除来反映钠摄入。本课题拟对钠清除代表钠摄入的可靠性进行研究。方法 对40名稳定的CAPD患者在开始时和3个月后分别进行饮食钠摄入的调查，测定腹膜透析液及尿中钠清除量，并通过生物电阻抗法测定体液容量水平。 结果 根据饮食中钠摄入量变化患者被分为2组：钠摄入增加组15例和下降组9例。 2组间钠摄入的变化差异有显著性 （ P < 0.05），体液容量变化差异亦有显著性（P<0.05），但2组间腹膜透析液钠清除、尿液钠清除及总钠清除的变化无统计学意义。结论 腹膜透析液及尿中钠清除皆不能如实反映 CAPD患者饮食中钠摄入，因此，对CAPD患者利用测定钠清除来反映钠摄入不够可靠。

Objective Dietary salt and fluid restriction is important in controlling fluid balance in CAPD patients. 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 to use TSR as a surrogate to TSI in CAPD patients. Methods Forty clinical stable CAPD patients were closely followed for three months. 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 assessment. Patients with increased sodium intake (group ISI) or decreased sodium intake (group DSI) (both >0.5g/d) were included into this study. Results 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 and TSR in both groups. No relationship was found between TSI and TSR. Fluid status deteriorated in group ISI and improved in group DSI ( P<0.05). Conclusion: Our study suggests that neither USR nor DSR reflects changes of sodium intake in diet in CAPD patients. Therefore, TSR (the sum of USR and DSR) should not be used to monitor TSI in this patient population.