Manzoni C, Di Filippo S, Corti M, Locatelli F
Department of Nephrology and Dialysis, Lecco Hospital, Italy.
Nephrol Dial Transplant. 1996 Oct;11(10):2023-30. doi: 10.1093/oxfordjournals.ndt.a027091.
It is well known that the difference between prescribed and delivered dialysis doses greatly affects the morbidity and mortality of dialysed patients. The on-line monitoring of delivered dialysis is therefore of paramount importance. Recently, a conductivity-based method for determining Kt/V on routine basis has been proposed.
The study was performed using a specially designed module (Biofeedback Module, COT, Hospal) which, when connected to a dialysis monitor, automatically determines effective ionic dialysance (ID). During three consecutive dialysis sessions, administered to each of eight patients at the same depurative efficiency, we determined Kt/V by using mean effective ionic dialysance and by assuming, as suggested, that urea distribution volume corresponded to 55% of body weight. This method was compared with the gold standard of the direct quantification method. The Kt/V was also calculated by using mean effective ionic dialysance and the volume of urea distribution derived from anthropometric parameters.
The Kt/V determined by using mean effective ionic dialysance and by assuming that urea distribution volume corresponded to 55% of body weight was heavily underestimated (-22%). This difference was due to both the overestimate of urea distribution volume (+17%) and underestimate of effective urea clearance (KUeff) (-11%). The mean Kt/V calculated on the basis of ionic dialysance and anthropometric volume was also underestimated (-23%) since this volume was overestimated (+17%). Nevertheless, ionic dialysance and urea clearance proved to be closely correlated (r2 = 0.89) so that effective urea clearance can be derived according to: Kueff = ID x 0.865 + 39.89.
In steady-state patients, once urea distribution volume has been correctly determined by means of direct quantification, effective urea clearance can be easily derived from ionic dialysance and Kt/V calculated on-line at each session, without blood sampling or any additional costs.
众所周知，规定的透析剂量与实际给予的透析剂量之间的差异对透析患者的发病率和死亡率有很大影响。因此，对实际给予的透析进行在线监测至关重要。最近，有人提出了一种基于电导率的常规测定Kt/V的方法。
本研究使用了一个专门设计的模块（生物反馈模块，COT，Hospal），该模块连接到透析监测仪时，可自动测定有效离子透析率（ID）。在以相同净化效率对8名患者进行的连续三次透析过程中，我们通过使用平均有效离子透析率并按照建议假设尿素分布容积相当于体重的55%来测定Kt/V。将该方法与直接定量法的金标准进行比较。还通过使用平均有效离子透析率和根据人体测量参数得出的尿素分布容积来计算Kt/V。
通过使用平均有效离子透析率并假设尿素分布容积相当于体重的55%来测定的Kt/V被严重低估（-22%）。这种差异是由于尿素分布容积高估（+17%）和有效尿素清除率（KUeff）低估（-11%）共同导致的。基于离子透析率和人体测量容积计算出的平均Kt/V也被低估（-23%），因为该容积被高估（+17%）。然而，离子透析率和尿素清除率被证明密切相关（r2 = 0.89），因此有效尿素清除率可根据以下公式得出：Kueff = ID x 0.865 + 39.89。
在稳定状态的患者中，一旦通过直接定量正确确定了尿素分布容积，就可以轻松地从每次透析时在线计算的离子透析率和Kt/V中得出有效尿素清除率，无需采血或产生任何额外费用。
