Comparative examination of various rectal tubes and contrast media for the reduction of intussusceptions.

The hydrodynamic influence of different rectal tube sizes, contrast media, and heights of the fluid column on hydrostatic reduction of intussusception was analyzed in vitro. Enemas were performed in dead rabbits to compare the filling speed of bowel with a liquid and a gaseous contrast medium. For hydrostatic reduction, tubing and rectal tube with a large caliber and a low viscosity contrast medium achieved a higher filling speed of colon and are expected to provide a higher force of reduction on the intussusceptum. A rectal tube with a large caliber can be more useful than an increase of the column height. Filling bowel with carbon dioxide was approximately 7 times faster than with meglumine sodium diatrizoate. Theoretical considerations allow the hypothesis that a gaseous medium provides a faster and steadier reduction than a liquid.