The purpose of this trial was to prepare for a large randomized trial comparing Arglaes film dressing, a recent innovation containing silver ions, against Tegaderm, a transparent polyurethane dressing. Thirty-one patients admitted to the intensive care unit and requiring the insertion of an arterial line or central venous catheter were recruited into the study. Skin swabs were taken from the insertion sites prior to catheterization and on removal of the intravascular device to measure skin colonization rate between the two dressings. The catheter tips were also cultured on removal to establish if there was a difference between the two groups. No statistical differences were found in bacterial growth between the two dressings.