Vital signs and serum electrolyte levels are well preserved after large volume water exchange in the colonic lumen used with the water exchange method.

BACKGROUND: Reports of water exchange (WE) colonoscopy did not describe complications, but the safety of the WE method has not been critically evaluated.

AIM: We report the vital signs, cardiac rhythm and serum electrolyte levels before and after large volume water exchange. Unsedated patients are chosen for evaluation to avoid the confounding effects of sedation medications.

PATIENT AND METHOD: Patients in two randomized controlled trials (RCT) comparing the use of air insufflations (AI) vs. WE method for unsedated colonoscopy without missing data of interest were identified. Study 1: Patients' vital signs and cardiac rhythm before (immediately before insertion of the colonoscope into the rectum) and after (immediately after removal of the colonoscope from the rectum) colonoscopy were tabulated. Study 2: In patients who agreed to have pre and post colonoscopy electrolyte evaluation, blood samples (2 mL each) were drawn within 5 to 10 min before and after colonoscopy for measuring the serum Na(+) and K(+) levels.

RESULTS: Study 1: There were no significant differences in vital signs before and after colonoscopy in either the AI or WE group. All patients were in normal sinus rhythm before and after the colonoscopy. Study 2: There were no significant differences between the serum Na(+) and K(+) before and after colonoscopy in either the AI or WE group.

CONCLUSION: Vital signs, cardiac rhythm and serum electrolyte levels are well preserved after large volume WE in the colonic lumen. The WE method is a safe modality in these regards.