Contamination of central venous catheters. The skin insertion wound is a major source of contamination

In a prospective controlled trial we compared the rates of catheter-tip contamination in central venous catheters inserted with or without skin contact. The study was designed so that each patient was their own control. All patients had a single-lumen central venous catheter and a Swan-Gantz sheet inserted through the skin. A Swan-Gantz catheter was inserted and retracted through the sheet thus avoiding contact with skin or subcutaneous tissue. Catheter-tip cultures were performed on removal of catheters. Thirty-three Swan-Gantz catheters were cultured and all were sterile. In the corresponding 33 sheets 16 (48.6%) yielded bacterial growth. Four of the sheets showed growth of more than 15 cfu. In the 26 single-lumen catheters, eight (30.8%) catheter-tips grew bacteria, and four of them had more than 15 colonies. The study supports the theory that the skin-insertion wound is a major source of catheter-contamination.