Study designs of evaluations included in the review
Randomised controlled trials (RCTs), quasi-randomised trials, and systematic reviews and meta-analyses of RCTs or quasi-randomised trials were eligible for inclusion.
Specific interventions included in the review
Studies that assessed vascular access gained by needleless closed systems, conventional closed systems or conventional open systems were eligible for inclusion. The included studies compared needleless closed systems with conventional open systems and needleless closed systems with conventional closed systems. The types of needleless connectors used were CLAVE (ICU Medical, Inc., San Clemente, USA), PosiFlow (Becton Dickinson, Utah, USA), Mutiflo hub (Clave, Ohmeda, Trappes, France), Multilumen Smartsite DNFC (Alaris Medical Systems, San Diego, USA) and the InterLink System. Where specified, conventional open systems used standard luer caps or standard luer caps with a hub protection box which was impregnated with antiseptic twice daily. Conventional closed systems used the PRN Luer slip adaptor.
Participants included in the review
Studies of patients in the hospital setting, with intravascular catheters in situ, were eligible for inclusion. The patients in the included studies had diverse underlying diseases and diverse types and numbers of intravascular lines: major heart surgery patients with several intravascular lines simultaneously; cardiac surgery patients with a central venous catheter with several access points; medical, surgical and trauma patients with a multi-lumen central venous catheter; patients (unclear specification) with a central venous catheter; diabetic and immunosuppressed patients who required intravenous placement for blood drawing for up to 3 days.
Outcomes assessed in the review
Studies that reported sufficient data for calculating the risks of catheter-related infection in the treatment and control groups were eligible for inclusion. The studies reported data related to:
catheter-associated bloodstream infection, defined according to the Centers for Disease Control and Prevention criteria;
catheter tip colonisation, defined as the presence of 15 or more colony-forming units (cfu)/mL in the semiquantitative culture described by Maki et al. (reference given), or the isolation of at least 1,000 cfu/mL in an unclearly specified semiquantitative culture technique;
hub inlet colonisation, defined as the presence of bacteria in a standard semiquantitative culture or the isolation of at least 100 cfu/mL in the semiquantitative culture;
skin colonisation around the insertion site, defined as the presence of bacteria in a standard semiquantitative culture; and
adaptor fluid colonisation, defined as any growth on blood agar incubated for 4 days or in tryptic soy broth incubated for 7 days.
How were decisions on the relevance of primary studies made?
Two reviewers independently assessed studies for inclusion in the review. Any disagreements were resolved through discussion with a third reviewer.