To the Editor: —We read with interest the recently featured article “Predictors of Postoperative Acute Renal Failure after Noncardiac Surgery in Patients with Previously Normal Renal Function” by Kheterpal et al.  1in Anesthesiology. We congratulate the authors on this excellent article. The importance of alterations in renal function in the perioperative period is not widely recognized by anesthesiologists. Hence, we appreciate the contribution of the authors on this subject.

During our own work on renal function, we have noticed a recent change away from using the Cockroft and Gault formula for estimation of Creatinine Clearance toward using the Modification of Diet in Renal Disease formula in view of the many drawbacks with the Cockroft and Gault formula.2,3,4,5We noted in the article significant findings related to renal function and obesity. These results may have looked different with the Modification of Diet in Renal Disease formula with respect to the obese patients in their population.

We would be curious if the authors could comment on their choice of formula for estimation of creatinine clearance in their article.

*A I Dupont Hospital for Children, Wilmington, Delaware.

Kheterpal S, Tremper KK, Englesbe MJ, O’Reilly M, Shanks AM, Fetterman DM, Rosenberg AL, Swartz RD: Predictors of postoperative acute renal failure after noncardiac surgery in patients with previously normal renal function. Anesthesiology 2007; 107:892–902
National Kidney Foundation: K/DOQI Clinical practice guideline to define chronic kidney disease: Evaluation, classification and stratification. Am J Kidney Dis 2002; 39:S1–266
National Kidney Foundation
Levey AS, Bosch JP, Lewis JB, Greene T, Rogers N, Roth D: A more accurate method to estimate glomerular filtration rate from serum creatinine: A new prediction equation. Ann Intern Med 1999; 130:461–70
Kaiske BL: Serum creatinine formulas to estimate kidney function, Brenner & Rector’s The Kidney, 8th edition. Edited by Brenner BM. Philadelphia, Saunders, 2007, pp 725–34Brenner BM
Froissart M, Rossert J, Jacquot C, Paillard M, Houillier P: Predictive performance of the modification of diet in renal disease and Cockroft–Gault equations for estimating renal function. J Am Soc Nephrol 2005; 16:763–73