Pre-spinal surgery skin antisepsis with povidone iodine-alcohol followed by chlorhexidine gluconate-alcohol versus povidone iodine-alcohol applied twice for prevention of surgical wound contamination by bacteria: a randomised, controlled trial.

Aims:To determine if sequential application of povidone iodine-alcohol (PVI) followed by chlorhexidine gluconate-alcohol (CHG) would reduce surgical wound contamination to a greater extent than PVI applied twice in spinal surgery patients. Patients and Methods: A single-centre, interventional, two arm, parallel group randomised controlled trial of 407 patients attending hospital for elective spinal surgery was conducted. For 203 patients, pre-surgical skin disinfection was by application of PVI (10% [w/w (1% w/w available iodine)] povidone iodine in 95% industrial denatured alcohol; Videne Alcoholic Tincture) twice and for 204 patients application of PVI once followed by application of CHG (2% [w/v] chlorhexadine gluconate in 70% [v/v] isopropyl alcohol; Chloraprep with tint). The primary outcome measure was post-skindisinfection surgical site contamination determined by aerobic and anaerobicbacterial growth from post-skin disinfection samples. Results: The detection of viable bacteria in any one of the post-skin disinfection samples (culture-positive) was significantly lower in the group treated with both PVI and CHG than in the group treated with PVI alone: 29.1% (59) vs 41.7% (85), P=0.009; relative risk, 0.574; 95% confidence interval, 0.380 to 0.866. Conclusions: Skin antisepsis with sequential application of PVI and CHG more effectively reduces surgical wound contamination than PVI alone.