Background: Povidone-iodine is a commonly used antiseptic for preparing the skin for regional anesthesia. However, chlorhexidine solution has been demonstrated superior for skin preparation before insertion of intravascular devices, taking of blood cultures and before epidural insertion in children. The information regarding the initial efficacy of these disinfectants has not yet been defined. The purpose of the present study was to investigate the initial efficacy of an alcohol-based chlorhexidine and povidone iodine solution as the antiseptic of choice for all regional techniques.

Material and Method: One hundred patients requesting regional anesthesia were randomly assigned to receive skin preparation with either single-use povidone iodine or alcohol-based chlorhexidine solution. Two quantitative skin cultures were obtained from the insertion site: one obtained just prior to skin disinfection and the other immediately following antisepsis after allowing it to air-dry.

Results: Complete data were available for 98 patients. Bacteriological examination revealed mainly coagulase negative Staphylococci (78.6%; 77/98). The proportion of subjects with a positive skin culture immediately after skin disinfection differed significantly between the povidone iodine and alcohol-based chlorhexidine groups (35% vs. 10%, respectively; p = 0.003). The incidence of positive skin culture was lower in the chlorhexidine group, with an absolute risk reduction (ARR) of 0.25, a relative risk reduction (RRR) of 71% and a number need to treat (NNT) of 4.

Conclusion: For skin disinfection prior to the neuraxial blockade procedure, the use of alcohol-based chlorhexidine compared with the use of povidone iodine lowered the incidence of insertion-site-colonization.

Keywords: Antiseptic, Anesthesia, Povidone iodine, Chlorhexidine