Specific problems of arterial, Swan-Ganz, and hemodialysis catheters.

In our experience, the incidence and pathogenesis of colonization may vary in different types of catheters. Arterial, Swan-Ganz, and hemodialysis catheters are good examples of this problem. This observation has implications for diagnosis, and the best method for each type of catheter may not be the same. In our opinion, laboratory diagnosis in daily practice should be limited to external surface cultures of the tip of intravascular catheters. Intraluminal cultures should be limited to research purposes, except in catheters used for parenteral nutrition or hemodialysis. In this case, the intradermal segment gives more sensitive information. Sensitivity in diagnosing pulmonary artery colonization can be improved by evaluating both the tip and intradermal segments. In presence of an indwelling introducer the intradermal segment should be replaced by the introducer tip.