title: Preoperative dehydration increases risk of postoperative acute renal failure in colon and rectal surgery.
abstract: OBJECTIVE
  There is limited data regarding the effects of preoperative dehydration on postoperative renal function. We sought to identify associations between hydration status before operation and postoperative acute renal failure (ARF) in patients undergoing colorectal resection.
  
  
  METHODS
  The NSQIP database was used to examine the data of patients undergoing colorectal resection from 2005 to 2011. We used preoperative blood urea nitrogen (BUN)/creatinine ratio >20 as a marker of relative dehydration. Multivariate analysis using logistic regression was performed to quantify the association of BUN/Cr ratio with ARF.
  
  
  RESULTS
  We sampled 27,860 patients who underwent colorectal resection. Patients with dehydration had higher risk of ARF compared to patients with BUN/Cr <10 (AOR, 1.23; P = 0.04). Dehydration was associated with an increase in mortality of the affected patients (AOR, 2.19; P < 0.01). Postoperative complication of myocardial infarction (MI) (AOR, 1.46; P < 0.01) and cardiac arrest (AOR, 1.39; P < 0.01) was higher in dehydrated patients. Open colorectal procedures (AOR, 2.67; P = 0.01) and total colectomy procedure (AOR, 1.62; P < 0.01) had associations with ARF.
  
  
  CONCLUSIONS
  Dehydration before operation is a common condition in colorectal surgery (incidence of 27.7 %). Preoperative dehydration is associated with increased rates of postoperative ARF, MI, and cardiac arrest. Hydrotherapy of patients with dehydration may decrease postoperative complications in colorectal surgery.
authors.affiliation: Department of Surgery, School of Medicine, University of California, Irvine, 333 City Blvd. West Suite 1600, Orange, CA, 92868, USA.
authors.forename: Zhobin
authors.initials: Z
authors.lastname: Moghadamyeghaneh
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Phelan
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Carmichael
authors.forename: Steven D
authors.initials: SD
authors.lastname: Mills
authors.forename: Alessio
authors.initials: A
authors.lastname: Pigazzi
authors.forename: Ninh T
authors.initials: NT
authors.lastname: Nguyen
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Stamos
mesh_terms: D058186:Acute Kidney Injury / Q000453:epidemiology* / Q000209:etiology; D000368:Aged; D003107:Colorectal Surgery / Q000009:adverse effects*; D003681:Dehydration / Q000150:complications* / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D057234:Preoperative Period; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology