3334 Hydrogels and other lubricants in endoscopy.

Abstract

Background: Lubrication is commonly used in endoscopy despite little data on efficacy. Hydrogels are polymers, which when bonded to surfaces and wetted, become very effective lubricants. Hydrogels are biocompatible and could make very effective endoscopic lubricants. Aims: To measure the static and dynamic coefficient of friction of freshly excised porcine colonic tissue, using different lubricants including hydrogels, on the shaft of a colonoscope. Methods: The shaft of the endoscope was curved to form rails held in place by a wooden jig. A toboggan of known weight was constructed with colonic tissue stretched on the underside to run on the rails. The jig was tilted using a rotary table and control unit which allowed accurate measurements of the angles at which the toboggan started to move and the angle required to keep the toboggan moving using water, KY jelly, silicone spray and spray oil lubricants. Hydrogel measurements were made using hydrogel coated urinary catheters as the rails. Coefficient of friction was calculated for the different lubricants. Results: The static and dynamic coefficient of friction were difficult to measure for the lubricants other than hydrogels due to their viscosity resulting in very slow movements. The values for KY, silicone and oil were generally less than water, though not significantly. The static coefficient of friction was reduced by a factor of 6 for hydrogels and by a factor of 10 for dynamic coefficient of friction over all other lubricants. These results were significant(p