Sabry et al., J Nephrol Therapeutic 2011, 1:3 DOI: 10.4172/2161-0959.1000108 Volume 1 • Issue 3 • 1000108 J Nephrol Therapeutic ISSN: 2161-0959 JNT, an open access journal Open Access Case Report Hemodialysis Adequacy: A Comparative Multicenter Study Between OCM and Calculated Kt/V from Two Centers in the Gulf Alaa A Sabry 1 *, Khalid Alsaran 2 , Ahmd Yehia 2 , Eid M El-Shafey 3 and Anas Al-Yousef 4 1 Nephrology Division, Urology & Nephrology Center, Mansoura University, Mansoura university, Egypt 2 Prince Salman Center for Kidney Diseases, Riyadh, Kingdom of Saudi Arabia 3 Internal Medicine Department, Faculty Of Medicine, Tanta University, Tanta, Egypt 4 Nephrology Division, Internal Medicine Department, Jahra Hospital, Kuwait Abstract Introduction: Adequate delivered dose of solute removal (as assessed by urea reduction and calculation of Kt/V) is an important determinant of clinical outcome in chronic haemodialysis (HD) patients. This requires both prescription of an adequate dose of HD and regular assessment that the delivered treatments are also adequate. On line conductivity monitoring Kt/V OCM online clearance measurement (OCM) (OCM) -using sodium fux as a surrogate for urea- allows the repeated non-invasive measurement of Kt/V on each HD treatment. Methods: We prospectively studied 131 (63 males, 68 females) established chronic HD patients over 8 weeks period (1048 treatments). A pre and post dialyzer measurement of the conductivity is performed by two mutually independent temperature-compensated conductivity cells equipped with Fresenius 4008 S ® dialysis machines. Urea reduction was measured (once a week) by a single pool calculation using immediate post treatment sampling. No changes were made to any of the dialysis prescriptions over the study period. Values of calculated Kt/V (conventional method with Daugirdas’ formula) Kt/V Dau and simultaneously obtained online Kt/V OCM were compared. Results: There was a statistically signifcant difference between calculated Kt/V DAU and Kt/V OCM over the study period. The mean calculated Kt/V DAU was 1.459 ± 0.31, and mean OCM was 1.139 ± 0.14 (p = 0.000), yet there was moderate correlation between calculated Kt/V DAU and Kt/V OCM (r 2 = 0.59) (p = 0.000) (Figure 1). Conclusions: Online clearance measurement (OCM) results underestimates dialysis effciency compared to cal- culated Kt/V DAU values. This difference has to be considered when applying Kt/V OCM to clinical practice (Figure 2). *Corresponding author: Alaa Sabry, Assistant Professor of Nephrology, Mansoura Urology and Nephrology Center, Mansoura University, Egypt, Tel: 002-050-252- 4024; Fax: 002-050-226-3717; E-mail: asabry2040@yahoo.com Received August 08, 2011; Accepted December 16, 2011; Published December 18, 2011 Citation: Sabry AA, Alsaran K, Yehia A, El-Shafey EM, Al-Yousef A (2011) Hemodialysis Adequacy: A Comparative Multicenter Study Between OCM and Calculated Kt/V from Two Centers in the Gulf. J Nephrol Therapeutic 1:108. doi:10.4172/2161-0959.1000108 Copyright: © 2011 Sabry AA, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Keywords: Kt/V; Hemodialysis; Online clearance monitoring Introduction Quantifcation of the dialysis dose is an essential element in the management of chronic haemodialysis treatment because the adequacy of the dose has a profound efect on patient morbidity and mortality [1]. Te most useful and widely applied index to prescribe the dialysis dose (as well as to assess the dose which is actually delivered) is the Kt/V DAU formula [1]. It is now well recognized that an adequate delivery of haemodialysis (HD) dose (as measured by Kt/V derived from urea reduction) is a crucial determinant in clinical outcome of chronic HD patients [2]. Tis requires both prescription of an adequate dose of HD and regular assessment that the delivered treatments are also adequate [3]. Te greatest problem we are facing at the moment is to check whether the prescribed dialysis dose has actually been delivered. Tere is ofen a diference, sometimes large, between the prescribed and delivered dose [4]. Tere are many reasons why a discrepancy between calculated and delivered dose of extra-corporeal blood purifcation might exist. Failure of staf to ensure the pre-determined treatment time is given (usually in the face of variable patient resistance) is a common failing. However, other factors such as suboptimal needle placement, haemodynamic instability and progressive access malfunction all militate against this optimal delivery [5]. Bed-side Kt/V is currently determined using various kinetic models; the most widely used being the single-pool variable volume urea kinetic model (SPVV- UKM) [6]. Te European Best Practice Guidelines recommended as minimum treatment dose an equilibrated Kt/V = 1.2 [7], but in clinical practice this value cannot be achieved for every patient [8]. According to the guidelines, dialysis dose should be measured using a validated method [7]. Apart from blood sample-based methods, alternative methods determining dialysis dose have been developed, mostly based on measurements of conductivity [9] or of urea [10], recently also of ultraviolet absorbance in the spent dialysate [11]. On-line clearance monitors measure the diference in conductivity between the dialysate entering and leaving the dialyser with two diferent dialysate inlet electrolyte concentrations [12]. On-line clearance monitoring (OCM) allows dialysis dose to be monitored at every treatment with virtually no additional overheads. While it is unlikely that these non-invasive measurements of Kt/V will replace routine blood sampling, OCM afords staf the opportunity to monitor unstable patients more efectively, identify problems quickly and assess the efect of remedial actions. Recently, advances in the on-line monitoring of conductivity during HD sessions have made the repeated measurement of Kt/V OCM on all HD treatment sessions a practical proposition [13]. Tis method has been shown to have an excellent correlation with Kt/V J o u r n a l o f N e p h r o l o g y & T h e r a p e u t i c s ISSN: 2161-0959 Journal of Nephrology & Therapeutics