Abstract
Occluded ERBD tubes and intact ERBD tubes which were experimentally soaked in bile collected through EN BD tubes were examined mainly by scanning electron microscope. Occluded ERBD tubes were filled with black-brownish materials on gross examination. These materials consisted of bacterial mass and brown-granular layers on light microscopy, and both were piled up each other and formed concentric circle appearance. This brown layer contained bilirubin calcium and others. Serial observations of ERBD tube soaked in bile revealed as follows : first, a few bacteria were attached locally on the tube surface and formed small colonies, and gradually spreaded on the whole surface of the tube, then the materials containing bilirubin calcium and others piled up the bacterial layers. Repeating these process progressed the occlusion of ERBD tube. It is considered that the bile flow volume is one of the most important facter for tube occlusion. It would be requested to develop the material which can interfere with the bacteria attachment to the tube surface or to maintain bile flow as much as possible for avoidance of ERBD tube occlusion.
