Antiseptic Agents

This is the authors' abstract. We don't add key points for this paper.

Myth: For an epidural injection, Betadine (povidone-iodine) is just as good a skin antiseptic as any of those modern expensive skin preps. Fact: Properly applied chlorhexidine in alcohol (ChloraPrep) is a superior skin antiseptic. Application of an antiseptic to the skin before spinal interventions is an important component of the broader topic of surgical site infection risk management. Indeed, an effective skin antiseptic is only one of the required elements of a good aseptic technique. Although rare, three types of infections have been reported after routine epidural steroid injection: superficial skin injection site infection, discitis, epidural abscess. There are two topical solutions commonly utilized to disinfect clean intact skin: povidone-iodine (PVI) and chlorhexidine gluconate (CHG). Both are commercially available, as either an aqueous or alcohol-based solution. PVI, CHG, and alcohol all have broad-spectrum antimicrobial coverage against gram-positive and gram-negative bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), fungi, virus, and mycobacterium tuberculosis. The effectiveness of these agents has not degraded over time. PVI works primarily through the release of free elemental iodine, which denatures microbial proteins and damages microbial DNA. CHG’s mechanism of action is primarily through disruption of microbial cell membranes. Alcohol works through a combination of disruption of microbial cell membranes and denaturation of proteins. The addition of alcohol improves the antiseptic profile of both PVI and CHG. Compared with aqueous-based antiseptics, alcohol-based antiseptics have a broader antimicrobial coverage, a briefer application process, a more rapid onset of action, and a longer duration of action. CHG 2% in alcohol 70% kills >99.999% of the 23 most common bacterial skin flora in less than three minutes. No skin antiseptic can eliminate all microbes because some reside deep off the surface in glands. The most important safeguard is to ensure that any skin antiseptic used must be allowed to completely dry before initiating an intervention. Optimal antimicrobial activity of all preps requires careful adherence to application instructions provided by the manufacturer. Alcohol-based surgical preps are flammable until fully dried and require vigilance. Many laboratory and clinical studies have been conducted comparing the relative safety and effectiveness of the various antiseptic agents in reducing both laboratory-determined bacterial colony counts and surgical site infections (SSIs). Alcohol-based skin preps are superior to aqueous-based preps in all measures. There is abundant evidence validating the superiority of CHG in alcohol over all other preparations. Several systematic reviews and meta-analyses have yielded consistent results that the lowest risk of SSI follows the use of ChloraPrep (CHG 2% in alcohol 70%), and the reduction of infectious complications is in the order of 30%. Use of 70% alcohol, by itself, has not been adequately studied as a preprocedural skin antiseptic, but compared with Betadine Paint, it possesses a broader antimicrobial spectrum, is quick to apply, has a rapid onset, is not messy, and is less expensive. Adverse events such as skin irritation, erythema, and pruritus attributed to CHG and PVI are uncommon and are comparable. Several medical societies have endorsed the routine use of ChloraPrep specifically for spinal injections as the first choice for a skin antiseptic. The Spine Intervention Society’s (SIS’s) Practice Guidelines for Spinal Diagnostic and Treatment Procedures (Second Edition) and The American Society of Regional Anesthesia and Pain Management (ASRA) endorse ChloraPrep as the preferred skin disinfectant. The Centers for Disease Control and Prevention’s Guideline for the Prevention of Surgical Site Infection (2017) and the World Health Organization’s Global Guidelines for the Prevention of SSI recommend the use of chlorhexidine in alcohol for skin antisepsis because of its superior effectiveness and speed of application. Preoperative skin antisepsis with chlorhexidine in alcohol is not only more effective than preoperative skin antisepsis with iodine formulations for preventing SSI, it also results in cost savings. Concerns about the toxicity of chlorhexadine are based upon two reports on the effect of injection of large amounts of CHG directly into the cerebrospinal fluid in monkeys (1955) and into the anterior chamber of the eye in rats (1984), which resulted in neuronal damage. After 30 years of extensive clinical use, there are no reports of chlorhexidine causing nerve damage in humans, and the incidence of neurologic complications following neuraxial blockade utilizing ChloraPrep is no different than that of Betadine. Anything that kills bacteria such as CHG, PVI, and alcohol is potentially harmful to neural structures. Chlorhexidine 2% in isopropyl alcohol 70% (ChloraPrep) is the preferred choice for topical antisepsis of clean intact skin before spinal interventions. Povidone-iodine in alcohol (DuraPrep) is a reasonable alternative to ChloraPrep for patients who are sensitive to CHG. Aqueous-based skin preps have been proven to be less efficacious than alcohol-based preps. Directions for using ChloraPrep should be carefully followed, particularly systematically painting the area for 30 seconds (not scrub), avoiding solution pooling, and allowing time for complete drying. Funding sources: No funding was received in preparation of this manuscript. Conflicts of interest: No authors have any financial conflicts of interest to disclose. *An extended version of this FactFinder with complete references is available on the Spine Intervention Society Website at https://www.spineintervention.org/resource/resmgr/factfinder/FactFinder_2019_11_Antisepti.pdf. Comparison of four common preprocedural antiseptics used for clean intact skin CHG = chlorhexidine; PVI = povidone-iodine. Comparison of four common preprocedural antiseptics used for clean intact skin CHG = chlorhexidine; PVI = povidone-iodine.