Left-colon WEC May Reduce Insertion Time Compared With Whole-colon WEC.

Colonoscopy will be performed with conventional air insufflation during colonoscope insertion.

Water exchange method (The air pump was turned off before colonoscopy. During colonoscope insertion, residual air in lumen was suctioned and 37°C water was infused into lumen to obtain lumen visualization) was used in whole or left colon. Air was insufflated until cecum was reached or appendix opening was seen.