In both ICUs treatment of acute circulatory failure followed national and international guidelines, especially concerning septic shock. For all shock states, first line therapies were prompt vascular volume expansion in case of probable hypovolemia, immediate antibiotics in case of sepsis, invasive mechanical ventilation if necessary, quick use of continuous iv norepinephrine sellekchem to reach a MAP level above 65 mmHg, systematic echocardiography within the first hours, systematic dobutamine use in case of systolic myocardial dysfunction or low superior vena cava oxygen saturation after volume expansion.Patients with hypotension (defined as a systolic arterial pressure below 90 mmHg and/or a MAP below 65 mmHg over 10 minutes) for less than 12 h were included at the time (H1) they were carrying an arterial line and a bladder catheter.

Patients were not included in case of renal transplant, chronic haemodialysis, diabetic ketoacidosis, or diabetes insipidus. Patients were excluded if they died or were discharged before the ninth hour after inclusion (H9), if they were started on renal replacement therapy (RRT) before H9, or on diuretics before H9, if the arterial and/or bladder catheters were removed before H12, or if diabetes insipidus occurred between H1 and H72.

Data collectionWe recorded age, gender, size, body weight, underlying diseases (chronic hypertension, diabetes mellitus, chronic cardiac failure, liver cirrhosis, chronic renal insufficiency (defined as steady state creatinine clearance < 60 mL/minute), presence of solitary kidney), use of antihypertensive drugs before admission, type of antihypertensive drug used (angiotensin conversion enzyme (ACE) inhibitors; angiotensin II receptor blockers (ARB); diuretics, calcium inhibitors), administration of nonsteroidal anti-inflammatory drugs (NSAID), immunoglobulins, methotrexate, lithium, aciclovir, amphotericin, ciclosporin, tacrolimus, cisplatin, or protease inhibitors within 72 hours before inclusion, aminoglycosides or vancomycin within 96 hours before inclusion, iodinated contrast media within five days before inclusion, number of nephrotoxic drugs received before inclusion, presence of an urinary tract obstruction or not, urinary origin of sepsis, cause of shock (septic [20], cardiogenic, haemorrhagic, hypovolemic), simplified acute physiology score (SAPS II) [21], ICU and hospital stay outcome.

Recent serum creatinine at steady state was searched for all patients in hospital electronic registry and by calling the generalist practitioner. In case of an unsuccessful search, steady state serum creatinine was determined by the MDRD formula [22].We also recorded the time elapsed Anacetrapib between the beginning of hypotension and inclusion, the lowest MAP recorded before inclusion and the volume of vascular expansion within the six hours before inclusion.MAP and urine output, and catecholamine dosages were recorded hourly from H1 to H72.