title: Perioperative Hemodynamic Instability and Fluid Overload are Associated with Increasing Acute Kidney Injury Severity and Worse Outcome after Cardiac Surgery.
abstract: OBJECTIVE
  The study aimed to investigate patients' characteristics, fluid and hemodynamic management, and outcomes according to the severity of cardiac surgery-associated acute kidney injury (CSA-AKI).
  
  
  METHODS
  In a single-center, prospective cohort study, we enrolled 282 adult cardiac surgical patients. In a secondary analysis, we assessed preoperative patients' characteristics, physiological variables, and medication for intra- and postoperative fluid and hemodynamic management and outcomes according to CSA-AKI stages by the Renal risk, Injury, Failure, Loss, End-stage renal disease (RIFLE) classification. Variables of fluid and hemodynamic management were further assessed with regard to the need for postoperative renal replacement therapy (RRT) and in-hospital mortality by the area under the curve for the receiver operating characteristic (AUC-ROC) and multivariate regression analysis.
  
  
  RESULTS
  Patients with worsening RIFLE stage, were significantly older, had lower estimated glomerular filtration rate and higher body mass index, more peripheral vascular and chronic obstructive pulmonary disease, atrial fibrillation, and prolonged duration of cardiopulmonary bypass (all p < 0.01). Patients with more severe AKI stage stayed longer in the intensive care and hospital, had higher in-hospital mortality, and requirement for RRT (all p < 0.001). Also, with worsening RIFLE stage, patients had lower intraoperative mean arterial pressure (MAP); p = 0.047, despite higher doses of norepinephrine (p < 0.001). The intraoperative MAP showed the best discriminatory ability (AUC-ROC: >0.8) for and was independently associated with RRT and in-hospital mortality. Moreover, with increasing AKI severity, patients received significantly more fluid infusion, and required higher dose of furosemide; nonetheless, they had increased postoperative fluid balance.
  
  
  CONCLUSIONS
  In this cohort, reduced MAP and increased fluid balance were independently associated with increased mortality and need for RRT after cardiac surgery.
authors.affiliation: Research and Science Administration of Medical School Brandenburg (MHB), Brandenburg an der Havel, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Haase-Fielitz
authors.forename: Michael
authors.initials: M
authors.lastname: Haase
authors.forename: Rinaldo
authors.initials: R
authors.lastname: Bellomo
authors.forename: Paolo
authors.initials: P
authors.lastname: Calzavacca
authors.forename: Anke
authors.initials: A
authors.lastname: Spura
authors.forename: Hassina
authors.initials: H
authors.lastname: Baraki
authors.forename: Ingo
authors.initials: I
authors.lastname: Kutschka
authors.forename: Christian
authors.initials: C
authors.lastname: Albert
mesh_terms: D058186:Acute Kidney Injury / Q000175:diagnosis* / Q000209:etiology* / Q000401:mortality / Q000628:therapy; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D001826:Body Fluids; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D003422:Critical Care; D019468:Disease Management; D005260:Female; D006439:Hemodynamics; D017052:Hospital Mortality; D006801:Humans; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D063868:Patient Outcome Assessment; D059035:Perioperative Period; D011183:Postoperative Complications; D011379:Prognosis; D017582:Renal Replacement Therapy; D012307:Risk Factors; D012720:Severity of Illness Index; D014883:Water-Electrolyte Imbalance / Q000150:complications*