Thus, MLN8237 its value in septic critically ill patients in the ICU should be interpreted carefully before concluding that there is renal injury or estimating optimal MAP.ConclusionsA poor correlation between renal RI and MAP found only in septic and critically ill patients without AKI suggests that determinants of RI are numerous. Consequently, renal circulatory response to sepsis estimated by Doppler ultrasonography cannot reliably be predicted simply from changes in systemic hemodynamics. The value of a single RI measurement at ICU admission to determine optimal MAP remains uncertain.Key messages? RI, measured by Doppler ultrasonography, is correlated to MAP, age, and PaO2/FiO2 ratio only in septic and critically ill patients without AKI.? RI was increased in cases of AKI, but theses correlations were abolished.

? RI did not differ between patients who received or did not receive NE and was not correlated with the NE dose.? This correlation between RI and MAP in septic and critically ill patients without AKI is poor, suggesting that the determinants of RI are numerous.? A single RI measurement at admission of septic critically ill patients to predict persistent AKI or to determine optimal MAP seems insufficient.AbbreviationsAKI: acute kidney injury; CI: confidence interval; GFR: glomerular filtration rate; ICU: intensive care unit; MAP: mean arterial pressure; NE: norepinephrine; PaO2/FiO2: arterial partial pressure of oxygen/fraction of inspired oxygen; RBF: renal blood flow; RI: resistive index; RVR: renal vascular resistance; SAPS II: Simplified Acute Physiology Score II; sCr: serum creatinine.

Competing interestsThe authors declare that they have no competing interests.Authors’ contributionsAD conceived, designed, and coordinated the study. BM and JC helped to collect the clinical data. AO helped to carry out the statistical analysis. OJ-B, CF, HR, JR, GJ, CC and AO helped to critically revise the manuscript. All authors read and approved the final manuscript.NotesSee related commentary by Lerolle, http://ccforum.com/content/16/6/174AcknowledgementsThe authors thank Erwan Floch (Newmed Publishing Services) for revising the English and Olivier Branchard for his assistance in obtaining the consent of the ethics committee. Earlier this year, this study was presented in part at the Congress of the French Society of Critical Care in Paris, France.

Regional anticoagulation with citrate in continuous venovenous hemodialysis (CVVHD) reduces the frequency Batimastat of bleeding complications, provides longer filter lifetime [1-3], and may reduce mortality in ICU patients [4]. Reduced risk of bleeding complications and extracorporeal clotting using citrate CVVHD might be particularly beneficial in patients with impaired coagulation due to liver failure [5].