Flanigan M J
Department of Medicine, University of Iowa College of Medicine, Iowa City 52240, USA.
Am J Kidney Dis. 1998 Mar;31(3):495-501. doi: 10.1053/ajkd.1998.v31.pm9506687.
Peritoneal dialysis uses a biological "membrane," the peritoneum, to control solute movement between the patient and the dialysate. Equilibrium thermodynamic models predict that the movement of small molecules across the peritoneum will be restricted in proportion to their permeability indices, the available membrane surface area, and the solute concentration gradient between plasma water and dialysate. During peritoneal dialysis, the membrane surface area, dialysate flow, and solute concentration gradients are quite similar for small solutes such as creatinine and urea. Hence, the clearances of creatinine and urea should be proportional to one another in a ratio equal to that of their membrane permeabilities; if that ratio is known, a peritoneal creatinine clearance could be derived for any known peritoneal urea clearance, and vice versa. Analysis of patient data supports this hypothesis and suggests that if disparate normalization procedures are avoided, peritoneal dialysis patients without residual renal function will have difficulty consistently attaining the weekly normalized creatinine clearance of > or =60 L/1.73 m2 recommended by the National Kidney Foundation-Dialysis Outcomes Quality Indicators (NKF-DOQI) without achieving a weekly Kt/Vurea of > or =2.5.
腹膜透析利用生物“膜”，即腹膜，来控制患者与透析液之间的溶质移动。平衡热力学模型预测，小分子穿过腹膜的移动将与其通透指数、可用膜表面积以及血浆水与透析液之间的溶质浓度梯度成比例地受到限制。在腹膜透析过程中，对于肌酐和尿素等小分子溶质，膜表面积、透析液流量和溶质浓度梯度非常相似。因此，肌酐和尿素的清除率应彼此成比例，其比例等于它们的膜通透性之比；如果该比例已知，则可根据任何已知的腹膜尿素清除率得出腹膜肌酐清除率，反之亦然。对患者数据的分析支持这一假设，并表明如果避免不同的标准化程序，没有残余肾功能的腹膜透析患者将难以持续达到美国国家肾脏基金会透析预后质量倡议（NKF - DOQI）推荐的每周标准化肌酐清除率≥60 L/1.73 m²，而同时又不使每周的尿素Kt/V≥2.5。
