title: 12-hour versus 24-hour creatinine clearance in critically ill pediatric patients.
abstract: Measurement of renal function is important to optimize drug dosing in critically ill pediatric patients and to prevent dose-related toxicities caused by medications that are eliminated or metabolized by the kidney. In clinical practice, the 24-h creatinine clearance (CrCl) is used as a surrogate marker of renal function. However, a 24-h urine collection period delays the availability of the result and increases the potential for collection errors. This prospective, observational study was performed to determine whether a 12-h CrCl is comparable to the traditional 24-h CrCl and to assess whether CrCl could be reliably predicted by the Schwartz equation, which mathematically estimates a child's GFR. A 24-h urine sample was collected in two 12-h aliquots from 60 catheterized critically ill children (age 2 d to 18 y). CrCl and Schwartz glomerular filtration rate (GFR) estimates were determined for each 12- and 24-h period. Agreement between 12- and 24-h CrCl and between CrCl and Schwartz GFR estimates was assessed using intraclass correlation coefficients (ICCs). An ICC > or =0.8 was considered to indicate excellent agreement. The ICC between the first 12-h CrCl and 24-h CrCl was 0.9605. The ICC between the second 12-h CrCl and 24-h CrCl was 0.9602. The ICC between the 24-h CrCl and Schwartz GFR was only 0.7046. All comparisons of 12- and 24-h CrCl indicated excellent agreement. In summary, the Schwartz equation was not a reliable estimate of renal function in critically ill children, and a 12-h CrCl is just as accurate as the standard 24-h CrCl to assess renal function and guide drug dosing.
authors.affiliation: Department of Pharmacy, Hospital for Sick Children, 555 University Avenue, Toronto M5G 1X8, Ontario, Canada. sandra.pong@sickkids.ca
authors.forename: Sandra
authors.initials: S
authors.lastname: Pong
authors.forename: Winnie
authors.initials: W
authors.lastname: Seto
authors.forename: Mohamed
authors.initials: M
authors.lastname: Abdolell
authors.forename: Angela
authors.initials: A
authors.lastname: Trope
authors.forename: Karen
authors.initials: K
authors.lastname: Wong
authors.forename: Joann
authors.initials: J
authors.lastname: Herridge
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Harvey
authors.forename: Brian P
authors.initials: BP
authors.lastname: Kavanagh
mesh_terms: D000293:Adolescent; D002624:Chemistry, Clinical / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D003401:Creatine / Q000097:blood*; D003404:Creatinine / Q000097:blood; D016638:Critical Illness; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007677:Kidney Function Tests / Q000379:methods / Q000592:standards*; D008297:Male; D008962:Models, Theoretical; D011446:Prospective Studies; D013997:Time Factors
chemical_list: D003404:Creatinine; D003401:Creatine