SCANNING ELECTRON-MICROSCOPIC INVESTIGATIONS OF LARGE-BORE CATHETERS USED FOR EXTRACORPOREAL DETOXIFICATION METHODS

Forty two large-bore catheters which remained in position in 31 patien ts for a period of 2-73 days (average in situ time xBAR=26.8 days per patient) were investigated with use of scanning electron microscopy an d for bacterial colonization. Microbiological results indicated coloni zation of the intravascular large-bore catheters in 8 out of 42 cathet ers (19%). The scanning electron microscopic investigation provided mo rphological evidence for bacterial colonization in only three catheter s (7%). The three different catheter materials had small deposits of f ibrin and protein on the inner and outer surfaces after 2 days. This s econd layer covered the entire surface after 3 days and increased to a thickness of 3-60 mum during the following days. In this matrix, eryt hrocytes, thrombocytes and granulocytes could also be seen.