Impact of Water Exchange Colonoscopy on Serum Sodium and Potassium Levels: An Observational Study
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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.
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.
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.
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.
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.
KeywordsWater exchange Colonoscopy Serum electrolytes Colorectal cancer screening
Milli-equivalent per liter
Randomized controlled trial
Veterans Affairs Medical Center
The study was supported in part by an ASGE Endoscopy Outcome Research Grant (JWL) and ACG Clinical Research Grant (FWL), and by the C.W. Law Research Fund and the Research and Medical Services of the VANCHCS (JWL) and VAGLAHS (FWL).
Conflict of interest
JWL received research and educational support from Olympus America. The other authors have no conflict of interests relevant to this study to disclose.
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