Science, Medicine, and the Anesthesiologist

The World Health Organization recommends chlorhexidine solutions over povidone iodine solutions for surgical skin preparation. This advice is based on meta-analyses suggesting that chlorhexidine achieves better skin antisepsis than does povidone iodine. However, there is a concerning emergence of resistance to chlorhexidine. A noninferiority multicenter cluster-randomized trial was done in which 3,360 surgical patients were enrolled (cardiac, n = 2,187 [65%]; abdominal, n = 1,173 [35%]). The primary outcome was surgical site infection within 30 days for abdominal surgery and within 1 yr for cardiac surgery. The assessors were blinded. Noninferiority was predefined if the lower Wald 95% CI limit lay within a margin of −2.5%. The chlorhexidine and povidone iodine groups were alike with regard to demographic data, type and duration of surgery, and timing of prophylactic antibiotics. There was no difference in the rate of surgical site infections between the chlorhexidine group (n = 97, 5.5%) and the povidone iodine group (n = 80, 5.1%). The 95% CI of the difference (−1.1 to 2.0%) did not include the prespecified margin. Thus, when used to prevent surgical site infections in cardiac and abdominal surgery patients, a solution of povidone iodine in alcohol was noninferior to a solution of chlorhexidine gluconate in alcohol.

Take home message: This large, randomized study suggests that the purported superiority of chlorhexidine over povidone iodine for skin preparation may be overstated.