title: Impact of water exchange colonoscopy on serum sodium and potassium levels: an observational study.
abstract: BACKGROUND
  Concerns over the hypothetical adverse effects of water absorption and the disturbance of serum sodium and potassium levels prompted a quality assurance evaluation of water exchange (WE) colonoscopy.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the balance of water infused and suctioned in WE colonoscopy, and to quantify the acute impact on serum levels of sodium and potassium.
  
  
  METHODS
  Prospectively collected quality monitoring data of patients undergoing screening and surveillance colonoscopy at the Sacramento Veterans Affairs Medical Center were analyzed. Measurements were made of volume infused and suctioned during, and blood samples drawn 10 min before the start of and 10 min after completion of WE colonoscopy. Outcome measures included volume of water infused and suctioned, and serum levels of sodium and potassium.
  
  
  RESULTS
  A total of 140 patients (134M:6F), mean age of 59, underwent WE colonoscopy. Mean total volume of water infused was 1,839 mL. A negative balance of an average of 22 mL was documented. The mean (standard deviation) values (in meq/L) of serum levels of sodium 139.33 (2.27) and 139.28 (2.32), and potassium 3.86 (0.36) and 3.91 (0.39), before and after colonoscopy, respectively, showed no significant change.
  
  
  CONCLUSIONS
  The WE method allowed most of the water infused during colonoscopy to be recovered by suction at the completion of colonoscopy. Serum sodium and potassium levels did not change significantly within 10 min after completion. The WE method appears to be safe with minimal water retention and is devoid of acute fluctuations in serum levels of sodium and potassium.
authors.affiliation: Section of Gastroenterology, 111G, Sacramento VA Medical Center, VANCHCS, 10535 Hospital Way, Mather, CA, 95655, USA, jwleung@ucdavis.edu.
authors.forename: Joseph W
authors.initials: JW
authors.lastname: Leung
authors.forename: Rodelei
authors.initials: R
authors.lastname: Siao-Salera
authors.forename: Ovanes
authors.initials: O
authors.lastname: Abramyan
authors.forename: Surinder K
authors.initials: SK
authors.lastname: Mann
authors.forename: Gregory
authors.initials: G
authors.lastname: Ward
authors.forename: Andrew
authors.initials: A
authors.lastname: Yen
authors.forename: Rebeck
authors.initials: R
authors.lastname: Gutierrez
authors.forename: Felix W
authors.initials: FW
authors.lastname: Leung
mesh_terms: D015415:Biomarkers / Q000097:blood; D003113:Colonoscopy / Q000009:adverse effects* / Q000379:methods / Q000592:standards; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000097:blood*; D011446:Prospective Studies; D011785:Quality Assurance, Health Care; D012964:Sodium / Q000097:blood*; D014867:Water / Q000009:adverse effects
chemical_list: D015415:Biomarkers; D014867:Water; D012964:Sodium; D011188:Potassium