Methods This multicentre randomised, non-blinded equivalence trial recruited adults (≥18 years) with an intravenous
catheter of expected use longer than 4 days from three hospitals in Queensland, Australia, between May 20, 2008, and
Sept 9, 2009. Computer-generated random assignment (1:1 ratio, no blocking, stratifies ed by hospital, concealed before
allocation) was to clinically indicated replacement, or third daily routine replacement. Patients, clinical staff, and
research nurses could not be masked after treatment allocation because of the nature of the intervention. The primary
outcome was phlebitis during catheterisation or within 48 h after removal. The equivalence margin was set at 3%.
Primary analysis was by intention to treat. Secondary endpoints were catheter-related bloodstream and local infections,
all bloodstream infections, catheter tip colonisation, infusion failure, catheter numbers used, therapy duration,
mortality, and costs. This trial is registered with the Australian New Zealand Clinical Trials Registry, number
ACTRN12608000445370.