Depner T A, Keshaviah P R, Ebben J P, Emerson P F, Collins A J, Jindal K K, Nissenson A R, Lazarus J M, Pu K
University of California at Davis, Sacramento, USA.
J Am Soc Nephrol. 1996 Mar;7(3):464-71. doi: 10.1681/ASN.V73464.
Quantitation of hemodialysis by measuring changes in blood solute concentration requires careful timing when taking the postdialysis blood sample to avoid errors from postdialysis rebound and from recirculation of blood through the access device. It also requires complex mathematical interpretation to account for solute disequilibrium in the patient. To circumvent these problems, hemodialysis can be quantified and its adequacy assessed by direct measurement of the urea removed in the dialysate. Because total dialysate collection is impractical, an automated method was developed for measuring dialysate urea-nitrogen concentrations at frequent intervals during treatment. A multicenter clinical trial of the dialysate monitoring device, the Biostat 1000 (Baxter Healthcare Corporation, McGaw Park, IL) was conducted to validate the measurements of urea removed, the delivered dialysis dose (Kt/V), and net protein catabolism (PCR). The results were compared with a total dialysate collection in each patient. During 29 dialyses in 29 patients from three centers, the paired analysis of urea removed, as estimated by the dialysate monitor compared with the total dialysate collection, showed no significant difference (14.7 +/- 4.7 g versus 14.8 +/- 5.1 g). Similarly, measurements of Kt/V and PCR showed no significant difference (1.30 +/- 0.18 versus 1.28 +/- 0.19, respectively, for Kt/V and 42.3 +/- 15.7 g/day versus 52.2 +/- 17.4 g/day for PCR). When blood-side measurements during the same dialyses were analyzed with a single-compartment, variable-volume model of urea kinetics, Kt/V was consistently overestimated (1.49 +/- 0.29/dialysis, P < 0.001), most likely because of failure to consider urea disequilibrium. Because urea disequilibrium is difficult to quantitate during each treatment, dialysate measurements have obvious advantages. The dialysate monitor eliminated errors from dialysate bacterial contamination, simplified dialysate measurements, and proved to be a reliable method for quantifying and assuring dialysis adequacy.
通过测量血液溶质浓度变化来定量血液透析时，采集透析后血样需要仔细计时，以避免透析后反弹及血液通过通路装置再循环导致的误差。这还需要复杂的数学解释来考虑患者体内的溶质不平衡。为规避这些问题，可通过直接测量透析液中清除的尿素来定量血液透析并评估其充分性。由于收集全部透析液不切实际，因此开发了一种自动方法，用于在治疗期间频繁测量透析液尿素氮浓度。开展了一项关于透析液监测设备Biostat 1000（百特医疗保健公司，伊利诺伊州麦高公园）的多中心临床试验，以验证尿素清除量、透析剂量（Kt/V）和净蛋白分解代谢（PCR）的测量结果。将结果与每位患者的全部透析液收集结果进行比较。在来自三个中心的29例患者的29次透析过程中，透析液监测仪估算出的尿素清除量与全部透析液收集量的配对分析显示无显著差异（分别为14.7±4.7 g和14.8±5.1 g）。同样，Kt/V和PCR的测量结果也无显著差异（Kt/V分别为1.30±0.18和1.28±0.19，PCR分别为42.3±15.7 g/天和52.2±17.4 g/天）。当使用单室可变容积尿素动力学模型分析相同透析过程中的血液侧测量结果时，Kt/V一直被高估（每次透析为1.49±0.29，P<0.001），最可能的原因是未考虑尿素不平衡。由于每次治疗期间尿素不平衡难以定量，透析液测量具有明显优势。透析液监测仪消除了透析液细菌污染导致的误差，简化了透析液测量，并且被证明是一种可靠的定量和确保透析充分性的方法。
