title: Fluid balance as an early indicator of acute kidney injury in CV surgery.
abstract: BACKGROUND
  We hypothesized that positive fluid balance (FB) is the result of intraoperative kidney injury and associated renal vasoconstriction, and therefore may be an early clinical indicator of acute kidney injury (AKI). Since rapid changes in fluid volume occur during cardiovascular (CV) surgery, we investigated the influence of immediate postoperative FB on AKI.
  
  
  METHODS
  Data from the Nesiritide Study were retrospectively analyzed to investigate the association between FB and AKI.
  
  
  RESULTS
  Patients were classified into a negative FB (NegFB, median -1,221 ml, IQR -1,974 to -653 ml, n = 71) and a PosFB (median 849 ml, IQR 328 - 1,552 ml, n = 19) group based on FB status in the first 24 h postoperatively. The PosFB group had a higher incidence of AKI (NegFB 25.3% vs. PosFB 47.3%, p = 0.090) compared to the NegFB group. The difference in the incidence of AKI was significantly higher (NegFB 25.3% vs. high- PosFB 80%, p = 0.001) in the subset of patients who had FB ≥ 849 ml (highPosFB, n = 10). The highPosFB group demonstrated a significantly elevated risk for AKI in both unadjusted (OR = 9.8, 95% CI 1.9 - 51.2, p = 0.007) and multivariate models (OR = 8.1, 95% CI 1.5 - 45.1, p = 0.03).
  
  
  CONCLUSIONS
  PosFB in the immediate postoperative period may be an independent early indicator of AKI in patients undergoing CV surgery.
authors.affiliation: Division of Nephrology, Hypertension and Transplantation, University of Florida, Gainesville, FL, USA.
authors.forename: Bhagwan
authors.initials: B
authors.lastname: Dass
authors.forename: Michiko
authors.initials: M
authors.lastname: Shimada
authors.forename: Ganesh
authors.initials: G
authors.lastname: Kambhampati
authors.forename: Noel I
authors.initials: NI
authors.lastname: Ejaz
authors.forename: Amir A
authors.initials: AA
authors.lastname: Arif
authors.forename: Abutaleb A
authors.initials: AA
authors.lastname: Ejaz
mesh_terms: D058186:Acute Kidney Injury / Q000209:etiology* / Q000401:mortality / Q000503:physiopathology / Q000628:therapy; D000368:Aged; D006348:Cardiac Surgical Procedures / Q000009:adverse effects* / Q000401:mortality; D005431:Florida; D006801:Humans; D015994:Incidence; D007668:Kidney / Q000098:blood supply / Q000503:physiopathology*; D016015:Logistic Models; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D016032:Randomized Controlled Trials as Topic; D017582:Renal Replacement Therapy; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014554:Urination; D014656:Vascular Surgical Procedures / Q000009:adverse effects* / Q000401:mortality; D014661:Vasoconstriction; D014882:Water-Electrolyte Balance