Water exchange and suction removal of all residual air in the colonic lumen both contribute to attenuation of insertion pain in a learning curve study.

PURPOSE: Water exchange colonoscopy significantly reduces insertion pain. We report a learning curve experience.

METHOD: Historic cohort was examined by usual air insufflation during scope insertion. Water exchange in consecutive groups using escalating volumes (group 1 to 3) of infused water, and transitioned from leaving residual air initially unattended (group 1 and 2) to suction removal of all residual air in subsequent practice (group 3). pain (0=none, 10=most severe) was assessed at 2 to 3-minute intervals during insertion or at any time the patient voiced discomfort. Procedural outcomes were recorded.

RESULTS: Compared with the historic cohort examined by air insufflation, We produced a significantly lower proportion of patients with poor bowel preparation (≤6% vs. 18.9%, p=0.005). From group 1 to 2, in the presence of a significant increase in volume of water exchanged (volume infused, 954±283 vs. 791±263, p=0.004; volume aspirated, 776±376 vs. 657±183, p=0.120) without suction removal of residual air, there was a non-significant reduction of insertion pain (2.4±2.9 vs. 3.2±3.1, p=0.198). suction removal of all residual air necessitated exchange of even larger volumes of water (1074±533, p=0.023) in group 3; and a further significant decrease of pain score to 1.3±2.4 (p=0.043). a progressive significant increase in insertion time was noted as the volume of water exchanged escalated alongside residual air aspirated (p=0.001).

CONCLUSION: Unrestricted water exchange enhances pain reduction. suction removal of all residual air in the colonic lumen further attenuates insertion pain. Both maneuvers contribute to optimizing reduction of insertion pain in the current learning curve study.