programmed by Stephen Z Fadem

Corrected Standard Kt/V

THE PATIENT

Male Female
Feet inches Centimeters
feet inches
cms
Weight in kg
Age in years
Hgb (Hemoglobin in grams)
Body Water Percent (from below)*
Volume of distribution (by percent):vr
TBWWatson??? Anthropometric vol
BSADubois??? Body Surface Area
(anthropometric vol / body surface area): san_ratio
(anthropometric vol / body surface area)/20: san_ratio
Check Watson and DuBois equations

DIALYSIS

K (dialyzer clearance in cc/min)
T (time of dialysis in minutes)
Number of treatments per week

Kt/Vs

Kt/V (estimated):???
Effective spKt/V (corrected for hgb):???
Estimated equilibrated eKt/Vurea (Clearance turea = 35 min): ktve
Single Pool (sp) Kt/Vurea(Tattersall): ktve
Standard Kt/V: standardized ktv per week
SAn-std Kt/V: san_stdper week

References

  1. Daugirdas JT, Greene T, Chertow G and Depner TA. Clin J Am Soc Nephrol 5:1628-1636,2010
  2. Watson PE, Watson ID, Batt RD. Am J Clin Nutr 33:27-39, 1980
  3. DuBois D, DuBois EF. Arch Intern Medicine. 17:863-71, 1916
  4. Daugirdas JT. Simplified equations for monitoring Kt/V, PCRn, eKt/V, and ePCRn.Adv Ren Replace Ther. 1995 Oct;2(4):295-304.
  5. Leypoldt JK. Hemodial Int. 8:193-7, 2004
  6. Tattersall JE, DeTakats D, Chamney P, Greenwood RN, Farrington K: The post-hemodialysis rebound: Predicting and quantifying its effect on Kt/V. Kidney Int 50:2094-2102, 1996
  7. TOUCHCALC.com
  8. Touchcalc Kt/V Formulas
  9. Calculating Dialyzer Clearance

*Volume of distribution = 60% weight for men, 50% for women and 45% for elderly women)

The first article above addressed the concern that in a subgroup analysis of the HEMO study, women had a lower death rate, but not men when dialyzed to a higher Kt/V. (Also, when women were dialyzed at a lower Kt/V they had a higher mortality rate). The Kt/V formula in HEMO was normalized for volume (V). But, women and men have different volume of distribution and body surface area characteristics. The volume per unit of surface area is lower for women than for men. In their paper, Daugirdas, Greene, Chertow and Depner rescaled the standard Kt/V (different from the spKt/V or e Kt/V) but correcting it for the ratio of Anthropometric Vol/BSA. The rescaled data suggests that to provide adequate dialysis dosing woman will need a higher standardized Kt/V than men, and thus a higher spKt/V.


© 2008-14, Stephen Z. Fadem, M.D., FASN. All rights reserved. No part of this application may be duplicated without written permission from the author.

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