Subject Category: Endoscopy

Am J Gastroenterol 2009; 104:2935–2941; doi:10.1038/ajg.2009.429; published online 28 July 2009

Effectiveness of Warm Water Consumption to Reduce Patient Discomfort During Colonoscopy: A Randomized Controlled Trial

Hyuk Lee MD1,2, Jae J Kim MD1, Byung-Hoon Min MD1, Jun Haeng Lee MD1, Young-Ho Kim MD1, Dong Kyung Chang MD1, Jin Yong Kim MD1, Poong-Lyul Rhee MD1 and Jong Chul Rhee MD1

  1. 1Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
  2. 2Department of Internal Medicine, Armed Forces Capital Hospital, Seongnam, Korea

Correspondence: Jae J. Kim, MD, Division of Gastroenterology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Irwon-dong 50, Gangnam-gu, Seoul 135-710, Korea. E-mail: jjkim@skku.edu

Received 11 March 2009; Accepted 23 June 2009; Published online 28 July 2009.





Colonic spasm, a relatively common problem during colonoscopy, may interfere with intubation and examination. This study was conducted to compare the effect of warm water consumption before unsedated colonoscopy on the incidence of spasm, pain, and technical difficulties. In addition, we studied the associations between attributes of patients and the degree of pain experienced by them during procedures undertaken after warm water consumption.



A prospective, randomized, controlled, and investigator-blinded study was conducted in which three groups of patients underwent unsedated colonoscopies. Those randomized to group A (n=64) were instructed to drink 2 l of warm water and 90 ml of sodium phosphate (NaP) solution before colonoscopy. For comparison, those randomized to groups B (n=64) and C (n=64) were instructed to drink 2 l of cold water and 90 ml of NaP solution, or 90 ml of NaP solution without any additional water, respectively. Patient demographics, procedure-related factors, and degree of spasm, pain, and technical difficulty were assessed.



Ileal intubation and withdrawal times were significantly shorter for group A than for groups B and C (P<0.001 and P<0.001, respectively). There was no significant difference between groups in the degree of spasm reported by the endoscopist. The level of pain at the sigmoid colon and splenic flexure during colonoscopy was lower for group A than for groups B and C on both advancement and withdrawal of the colonoscope (P<0.001 and P<0.001, respectively). The level of discomfort 2 h after the completion of endoscopy was lower for group A than for the other groups. (P=0.001). A subgroup analysis showed that warm water consumption was especially beneficial for patients <40 years of age and for those with irritable bowel syndrome. A multivariate analysis showed that warm water consumption before colonoscopy (odds ratio (OR) 0.22; 95% confidence interval (CI): 0.09–0.48 vs. the cold water group and OR 0.34; 95% CI: 0.16–0.73 vs. the no water group) was an independent factor for the reduction of pain during colonoscopy.



The intake of warm water before unsedated colonoscopy reduces procedure-related pain and technical difficulty, especially in patients who are young or have irritable bowel syndrome, even though it does not improve the frequency of visible spasmodic events.