To investigate the effect of different temperature water on water infusion colonoscopy.

This is a randomized, controlled trial that is carried out from August 2017 to February 2018 at a single center and a total of 300 subjects who underwent colonoscopy examination for cancer screening were included in this study. The patients were randomized to three groups: air insufflation group, cool water group (22℃), warm water group (38℃). The colonoscopy procedures were performed by three experienced endoscopist without any sedation. The following parameters were assessed: patients′ abdominal pain scores evaluated by the visual analogue scales (VAS), the cecal intubation time, the cecal intubation rate, the polyp detection rate, position exchange, abdominal compression, the degree of satisfaction, withdrawal time, diagnosis results.

There was significance difference in the abdominal pain (5.5±4.0; 3.0±2.0; 3.0±1.0), the cecal intubation time (187.00±131.25s; 268.00±89.50 s; 250±103.50s), withdrawal time (137.5±62.00 s; 156.50±76.25s; 156.00±67.00s) and the degree of satisfaction (74%; 87%; 90%) between the three groups (P<0.05). Other outcomes were no different including the cecal intubation rate (94%; 98%; 97%), the polyp detection rate (19.15%; 24.49%; 23.71%), abdominal compression, position exchange (P>0.05). The abdominal pain scores in the air insufflation group is much higher than two water infusion groups (P<0.05), but there is no difference between the two water infusion groups (P>0.05); the degree of satisfaction in the air insufflation group is much lower than two water infusion groups (P<0.05), but there is no difference between the two water infusion groups (P>0.05); the cecal intubation time and withdrawal time in the two water infusion groups are longer than air insufflation group (P<0.05), there is no difference between the two water infusion groups (P>0.05).

Although water method needs more time to reach the cecum, it can reduce abdominal pain and improve degree of satisfaction compared with the air method. There is no difference between the warm water group and the cool water group in abdominal pain scores, the cecal intubation time, withdrawal time, degree of satisfaction, the cecal intubation rate, the polyp detection rate, abdominal compression, position exchange. Therefore, water do not need to be warmed in water infusion colonoscopy.