Kt/V Calculations for the Assessment of Hemodialysis Adequacy

Wt 0.10 0.08 0.06 0.04 1.80 0.02 0.00

1.60

1.40

Kt/V 1.20

1.00

0.80

0.60 0.40 0.50 0.60 0.70 0.80 URR We have found that the Keshaviah Quick Kt/V formula most closely correlates with both of the more complex Kt/V calculations that Spectra offers - the Daugirdas II Natural Log and Depner Full UKM Kt/V (see Figures 2 & 3).

Comparison of Kt/V Formulas to UKM Kt/V Comparison of Kt/V Formulas to UKM Kt/V 1500 Patient Results 0.6 to 2.0

2.20 2.20 2.00 2.00 1.80 1.80 1.60

1.60 1.40 1.40 1.20 Kt/V Calculations for 1.00 1.20 0.80 1.00 0.60 the Assessment of

0.40 1 4 7 0.80 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99 101 103 105 107 109 111 113 115 117 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79 82 85 88 91 94 97 112 115 118 100 103 106 109 121 Hemodialysis Adequacy Depner Full UKM Depner Full UKM Daugirdas II (Post BUN/Pre BUN-0.008 x t) + Daugirdas II (Post BUN/Pre BUN-0.008 x t) + Natural Log [4-3.5 x (Post BUN/Pre BUN)] x UF / Wt Natural Log [4-3.5 x (Post BUN/Pre BUN)] x UF / Wt Jindal 0.04*URR-1.2 Jindal 0.04*URR-1.2 Basile 0.023*URR-0.284 Basile 0.023*URR-0.284 Depner 0.026*URR-0.49 Depner 0.026*URR-0.49 Keshaviah 1.162*In(Pre/Pst) Keshaviah 1.162*In(Pre/Pst)

Figure 2 Figure 3

References 1 Daugirdas JT: Second generation logarithmic estimates of single-pool variable volume Kt/V: An analysis of error. J Am Soc Nephrol, 4:1205-1213, 1993. 2 Keshaviah, PR, Hanson, GI, Berkseth, RO and Collins, AJ 1988. A simplified approach to monitoring in vivo therapy prescription. Trans.Am. Soc. Artif. Organs, 34:620–2. 3 National Kidney Foundation. 1997. “NKF-DOQI clinical practice guidelines for hemodialysis adequacy”. Am. J. Kidney Dis., 30 (Suppl):S15–S66. 4 National Kidney Foundation. 2006. “NKF-DOQI clinical practice guidelines for hemodialysis adequacy, Update 2006”. Am. J. Kidney Dis., 48 (Suppl): S17:22-28. 5 Depner, TA 1994. Assessing adequacy of hemodialysis urea modeling. Kidney Int., 45:1522–35.

KDOQI™ is a trademark of the National Kidney Foundation, Inc. Spectra Laboratories, Inc. © 2013 Fresenius Medical Care Holdings, Inc. All rights reserved. Spectra and the Spectra logo are trademarks of Fresenius 525 Sycamore Drive • Milpitas, CA 95035 • 800-433-3773 Medical Care Holdings, Inc. or its affiliated companies. 8 King Road • Rockleigh, NJ 07647 • 800-522-4662 All other trademarks are the property of their respective owners. www.spectra-labs.com KTVBULLETIN_EXT Rev. 7/13 Kt/V Calculations for the Assessment of Spectra Laboratories offers the following Kt/V calculations for the assessment of hemodialysis adequacy: Hemodialysis Adequacy Quick Kt/V Calculations: Full Kt/V Calculations: There are a number of dialysis adequacy dialysis, the characteristics of the dialyzer being calculations published in the scientific literature used and the change in fluid volume. The Kt/V Keshaviah 1.162*ln (Pre BUN/Post BUN) Depner Full UKM Refer to Reference #5 that provide information regarding the efficiency calculation, although more accurate than the URR, Daugirdas II Natural Log (Post BUN/Pre BUN – 0.008 of dialysis. These calculations range from “quick” is complex and not easily calculated. However, in x t) + [4-3.5 x (Post BUN/Pre bedside Kt/V calculations that require only a its simplest form, the Kt/V is equal to the natural BUN)] x UF/Wt pre and post Blood Urea Nitrogen (BUN) result, log of the pre BUN/post BUN. By substitution, to full kinetic modeling calculations that require Kt/V relates to URR as the negative natural log additional patient information to calculate the of 1-URR. These basics become important in Note that the Quick Kt/V calculation can be The table below outlines the patient information most accurate Kt/V. deciding upon the calculations used to estimate ordered for patients individually, as part of the that is required for the different Kt/V calculations. dialysis efficiency. Although the National Kidney Foundation KDOQI™ patient’s LTO, or on an account basis and reported Quick Kt/V calculations require only pre and post Clinical Practice Guidelines recommend full kinetic In order to provide an easily calculated any time a pre and post BUN result is reported. BUN patient values, whereas the more complex Kt/V calculations require additional patient modeling as the preferred method for determining approximation of Kt/V, the URR equation was All of the above calculations are designed for 4 information, such as pre and post weight. dialysis efficiency , simpler Kt/V equations that modified by measuring patient values, creating patients receiving dialysis three times per week, correlate with the Urea Kinetic Modeling (UKM) normograms of the patient data (see Figure 1), between 2 and 4 hours per session. Patients Kt/V are also available. Equations that include and establishing the calculation that best receiving dialysis more than three days per week natural log function are preferable because they approximated the measured Kt/V. These formulas, should use the Standard Kt/V. more closely account for changes that take place commonly referred to as “quick” or “bedside” during the dialysis session. calculations, provide a simple means to arrive at Kt/V approximation without any additional The most common estimation of dialysis efficiency Patient Data Requirements for Kt/V Calculations: information than the pre and post BUN. is the Urea Reduction Ratio, or URR. BUN is used Kt/V Pre BUN Post BUN Pre Wt Post Wt UF Start Stop Frequency Schedule as a marker for uremia. The ratio is calculated by Calculations Time Time taking the amount of BUN present after the dialysis Wt Depner Full √ √ √ √ √ √ √ √ session (post BUN) and dividing it by the BUN UKM 0.10 0.08 0.06 0.04 1.80 present prior to the start of the dialysis session 0.02 Daugirdas II √ √ √ √ √ √ √ (pre BUN), using the formula: 0.00 Natural Log 1.60 Keshaviah √ √ URR (%) = 100 x (1 - (Post BUN/Pre BUN)) 1.40 A “quick” calculation, requiring only a pre and post BUN but incorporating the logarithmic The URR measures two points - the beginning and

Kt/V 1.20 expression of the change, most easily approximates the calculated Kt/V. end of dialysis. There is no urea in dialysate, so the differential between the patient’s blood and the dialysate is greatest during the beginning of the 1.00 session and least toward the end of the session. The URR is a simple average of this differential 0.80 between the beginning and end of dialysis. However, this ratio is not static and changes over 0.60 the course of the dialysis session. 0.40 0.50 0.60 0.70 0.80 URR Kt/V was first introduced in 1985 and incorporated the change in urea concentration over the time on Figure 1: Normogram4

CLINICAL PRACTICE GUIDELINES FOR HEMODIALYSIS ADEQUACY, UPDATE 2006 Because the Keshaviah Quick Kt/V formula also uses the natural log in its calculation, we have found it most closely correlates with both the complex Kt/V calculations that GUIDELINE 2: METHODS FOR MEASURING AND EXPRESSING HEMODIALYSIS DOSE Spectra offers - the Daugirdas II Natural Log Kt/V and the Depner Full UKM Kt/V. 2.4 The preferred method for measurement of the delivered dose is formal urea kinetic modeling. Other methods may be used, provided they give similar results and do not significantly If you would like to change your account based Kt/V to the Keshaviah formula, overestimate the modeled dose. 2.20 2.20 please contact Customer Service: 2.00 2.00 1-800-433-3773 (Milpitas, CA) • 1-800-522-4662 (Rockleigh, NJ) 1.80 1.80 1.60

1.60 1.40

1.40 1.20 1.00 1.20 0.80 1.00 0.60

Depner Full UKM Depner Full UKM Daugirdas II (Post BUN/Pre BUN-0.008 x t) + Daugirdas II (Post BUN/Pre BUN-0.008 x t) + Natural Log [4-3.5 x (Post BUN/Pre BUN)] x UF / Wt Natural Log [4-3.5 x (Post BUN/Pre BUN)] x UF / Wt Jindal 0.04*URR-1.2 Jindal 0.04*URR-1.2 Basile 0.023*URR-0.284 Basile 0.023*URR-0.284 Depner 0.026*URR-0.49 Depner 0.026*URR-0.49 Keshaviah 1.162*In(Pre/Pst) Keshaviah 1.162*In(Pre/Pst) Kt/V Calculations for the Assessment of Spectra Laboratories offers the following Kt/V calculations for the assessment of hemodialysis adequacy: Hemodialysis Adequacy Quick Kt/V Calculations: Full Kt/V Calculations: There are a number of dialysis adequacy dialysis, the characteristics of the dialyzer being calculations published in the scientific literature used and the change in fluid volume. The Kt/V Keshaviah 1.162*ln (Pre BUN/Post BUN) Depner Full UKM Refer to Reference #5 that provide information regarding the efficiency calculation, although more accurate than the URR, Daugirdas II Natural Log (Post BUN/Pre BUN – 0.008 of dialysis. These calculations range from “quick” is complex and not easily calculated. However, in x t) + [4-3.5 x (Post BUN/Pre bedside Kt/V calculations that require only a its simplest form, the Kt/V is equal to the natural BUN)] x UF/Wt pre and post Blood Urea Nitrogen (BUN) result, log of the pre BUN/post BUN. By substitution, to full kinetic modeling calculations that require Kt/V relates to URR as the negative natural log additional patient information to calculate the of 1-URR. These basics become important in Note that the Quick Kt/V calculation can be The table below outlines the patient information most accurate Kt/V. deciding upon the calculations used to estimate ordered for patients individually, as part of the that is required for the different Kt/V calculations. dialysis efficiency. Although the National Kidney Foundation KDOQI™ patient’s LTO, or on an account basis and reported Quick Kt/V calculations require only pre and post Clinical Practice Guidelines recommend full kinetic In order to provide an easily calculated any time a pre and post BUN result is reported. BUN patient values, whereas the more complex Kt/V calculations require additional patient modeling as the preferred method for determining approximation of Kt/V, the URR equation was All of the above calculations are designed for 4 information, such as pre and post weight. dialysis efficiency , simpler Kt/V equations that modified by measuring patient values, creating patients receiving dialysis three times per week, correlate with the Urea Kinetic Modeling (UKM) normograms of the patient data (see Figure 1), between 2 and 4 hours per session. Patients Kt/V are also available. Equations that include and establishing the calculation that best receiving dialysis more than three days per week natural log function are preferable because they approximated the measured Kt/V. These formulas, should use the Standard Kt/V. more closely account for changes that take place commonly referred to as “quick” or “bedside” during the dialysis session. calculations, provide a simple means to arrive at Kt/V approximation without any additional The most common estimation of dialysis efficiency Patient Data Requirements for Kt/V Calculations: information than the pre and post BUN. is the Urea Reduction Ratio, or URR. BUN is used Kt/V Pre BUN Post BUN Pre Wt Post Wt UF Start Stop Frequency Schedule as a marker for uremia. The ratio is calculated by Calculations Time Time taking the amount of BUN present after the dialysis Wt Depner Full √ √ √ √ √ √ √ √ session (post BUN) and dividing it by the BUN UKM 0.10 0.08 0.06 0.04 1.80 present prior to the start of the dialysis session 0.02 Daugirdas II √ √ √ √ √ √ √ (pre BUN), using the formula: 0.00 Natural Log 1.60 Keshaviah √ √ URR (%) = 100 x (1 - (Post BUN/Pre BUN)) 1.40 A “quick” calculation, requiring only a pre and post BUN but incorporating the logarithmic The URR measures two points - the beginning and