Are hydrostatic and pneumatic methods of intussusception reduction comparable?

The hydrostatic pressures and flow rates of barium sulphate and water soluble contrast in concentrations representative of those used for intussusception reduction were measured. The change of height with discharge of fluid from the filled kit was also assessed. A group of experienced paediatric radiologists and radiographers significantly underestimated the height to which contrast should be placed for intussusception reduction. The results indicate that baseline hydrostatic reduction pressures tend to be less and maximum pressures significantly less than those presently advocated for pneumatic reduction. This disparity may account for the apparent improvement in intussusception reduction rates reported for air enema when compared with barium enema. Intraluminal pressure monitoring during contrast enema would aid control of intussusception reduction but hydrostatic reduction would still be at a disadvantage because of lower flow rates. Where hydrostatic reduction is performed, the contrast density and height used should be set to give known pressure, according to local guidelines.