title: Iohexol clearance in unstable critically ill patients: a tool to assess glomerular filtration rate.
abstract: BACKGROUND
  Acute kidney injury (AKI) is associated with significant morbidity and mortality, particularly in unstable critically ill patients. In this context, serum creatinine concentration is an imperfect tool for estimating glomerular filtration rate (GFR), an index of renal function. The objective of this pilot study was to evaluate the feasibility of measuring iohexol clearance for GFR assessment in critically ill patients with acute circulatory failure at intensive care unit (ICU) admission.
  
  
  METHODS
  ICU patients were prospectively included within 12 h of acute circulatory failure; a non-toxic dose of iohexol (5 mL) was infused intravenously and iohexol plasma concentration decrease was measured over 24 h. Urinary iohexol concentration was measured in urine samples collected four times, every 6 h for 24 h. The Kidney Disease Improving Global Outcome score, measuring AKI, was calculated each day.
  
  
  RESULTS
  Among 18 patients with acute circulatory failure, AKI developed in 15; 14 showed decreased serum creatinine concentration during the first 24 h even though 10 presented AKI. The absolute variation in serum creatinine concentration was correlated with fluid balance over 24 h. Median [min; max] plasma clearance of iohexol was 39.4 mL/min [6.1; 154.0] and iohexol urinary clearance 32.8 mL/min [0.8-170.4]. The correlation between plasma and urinary clearance was ρ=0.97, p<0.0001.
  
  
  CONCLUSIONS
  GFR may be estimated by plasma iohexol clearance in unstable critically ill patients. This method is reliable, correlates very well with urinary iohexol clearance and does not depend on input/output fluid balance and fluid infusion, as compared with serum creatinine concentration.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Salmon-Gandonnière
authors.forename: Isabelle
authors.initials: I
authors.lastname: Benz-de Bretagne
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Mercier
authors.forename: Aurélie
authors.initials: A
authors.lastname: Joret
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Halimi
authors.forename: Stephan
authors.initials: S
authors.lastname: Ehrmann
authors.forename: Chantal
authors.initials: C
authors.lastname: Barin-Le Guellec
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood* / Q000652:urine*; D000368:Aged; D000369:Aged, 80 and over; D003404:Creatinine / Q000097:blood; D016638:Critical Illness; D005260:Female; D005919:Glomerular Filtration Rate; D006333:Heart Failure / Q000097:blood* / Q000652:urine*; D006801:Humans; D007262:Infusions, Intravenous; D007362:Intensive Care Units; D007472:Iohexol / Q000008:administration & dosage / Q000032:analysis*; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged
chemical_list: D007472:Iohexol; D003404:Creatinine