Research in context
Evidence before this study
In their 2011 guidelines for the prevention of intravascular catheter-related infections, the US Centers for Disease Control and Prevention stated that substances for skin preparation before catheter insertion was an unresolved issue. Although evidence was accumulating for use of chlorhexidine for skin preparation before catheter insertion, the higher clinical efficacy of chlorhexidine reported in studies could not be attributed to the chlorhexidine alone, but rather to the combination of chlorhexidine with alcohol, when compared with aqueous povidone iodine. Chlorhexidine in alcohol and povidone iodine in alcohol had not been compared head to head in a large-scale trial. The bactericidal efficacy of povidone iodine might be compromised by the presence of skin biomaterials, with possible partial inactivation of the antiseptic agent and so whether scrubbing before skin antisepsis before surgery should be done was also debated.
Added value of this study
We did a multicentre randomised controlled trial in 11 intensive care units in which all patients due to receive a central venous catheter, arterial catheter, or haemodialysis catheter were enrolled to receive skin preparation with 2% chlorhexidine–70% isopropyl alcohol or 5% povidone iodine–69% ethanol, both preceded or not by skin scrubbing, for antisepsis. Patients assigned to receive the chlorhexidine–alcohol combination had fewer catheter-related infections and catheter-related bloodstream infections compared with those assigned to receive the povidone iodine–alcohol combination. Skin scrubbing before skin antisepsis did not reduce the incidence of catheter colonisation.
Implications of all the available evidence
Chlorhexidine–alcohol combination should now be the standard of skin preparation before catheter insertion. Scrubbing of the skin with detergent should not. Whether the combination should be used for skin preparation before surgery remains to be established, as do the optimum concentration of chlorhexidine and type and concentration of alcohol to be combined with chlorhexidine.