Quality of lower limb preoperative skin preparation using colorless versus colored disinfectants–results of an experimental, randomized study in a close to reality setting

BACKGROUND: Appropriate preoperative skin cleansing is important to control surgical site infections. Both colored and colorless skin disinfectants are available, however certain types of skin preparation, such as octenidine-dihydrochloride with alcohol have a long residual antimicrobial effect but are available only in colorless form. We hypothesized that colorless skin disinfectants lead to more incomplete skin preparation of lower limbs compared to colored agents. METHODS: We randomly assigned healthy volunteers to undergo a determined skin cleansing protocol for total hip arthroplasty in the supine position to either a colored or colorless skin cleansing protocol. The adequacy of skin preparation was compared between orthopedic consultants and residents. The colorless disinfectant was mixed with a fluorescent dye and missed skin areas were visualized using UV lamps. Both preparations were photo-documented following standardized protocols. The primary outcome of interest was the number of legs with an incomplete scrubbed area. The secondary outcome was the cumulative skin area not disinfected. RESULTS: Fifty-two healthy volunteers (104 legs; 52 colored and 52 colorless) underwent surgical skin preparation. The number of legs incompletely disinfected was significantly higher in colorless compared to colored disinfectant group (38.5% (n = 20) vs. 13.5% (n = 7); p = 0.007). Regardless of the disinfectant, consultants performed better than the residents. When using colored disinfectant, residents incompletely prepared the site in 23.1% (n = 6) compared with 57.7% (n = 15) with a colorless disinfectant (p = 0.023). Conversely consultants using colored disinfectant incompletely prepared the site in 3.8% (n = 1) compared with 19.2% (n = 5) for colorless disinfectant (p = 0.191). The total amount of uncleansed skin was significantly higher using colorless skin disinfectant (mean ± standard deviation: 8.78 cm(2)± 35.07 vs. 0.65 cm(2) ± 2.66, p = 0.002). CONCLUSIONS: Application of colorless skin disinfectants for hip arthroplasty cleansing protocol led to decreased skin coverage among consultants and residents compared to colored preparations. Colored disinfectants remain the gold standard in hip surgery, however we should be aiming to develop newer colored disinfectants with long residual antimicrobial effects to enable visual control during the scrubbing process.