Effect of lidocaine gel on povidone-iodine antisepsis and microbial survival

PURPOSE: To determine whether the use of lidocaine gel prior to povidone-iodine antisepsis is associated with increased microbial survival. SETTING: Ophthalmology Department, Madigan Army Medical Center, Fort Lewis, Washington, USA. METHODS: A standardized suspension of Staphylococcus epidermidis was used to inoculate 5 blood agar plates that served as a control. A second group of 5 blood agar plates was inoculated, and then lidocaine gel was applied to the plates. A third group of 5 blood agar plates was inoculated, lidocaine gel was applied, and then povidone-iodine 5% was applied and allowed to cover the plates. A fourth group of 5 blood agar plates was inoculated, and then povidone-iodine 5% was allowed to cover the plates. Cultures of Staphylococcus aureus, Pseudomonas aeruginosa, and Haemophilus influenza were tested in a similar fashion. Microbial growth was evaluated after 24 hours. RESULTS: The number of colony forming units (CFUs) was similar in the control group and the S epidermidis, S aureus, and P aeruginosa lidocaine only and lidocaine with povidone-iodine groups. In these groups, each plate grew between 200 CFUs and 300 CFUs. In the Haemophilus influenza series, the lidocaine with povidone-iodine group had fewer CFUs than the control group. In all 4 series, the povidone-iodine only group had the least amount of CFUs, ranging from 0 to 6. CONCLUSIONS: The use of lidocaine gel before application of povidone-iodine 5% resulted in decreased effectiveness of antisepsis and increased microbial survivability. The increase in microbial survivability may increase the risk for postoperative infection in ocular surgery performed under topical anesthesia. J Cataract Refract Surg 2008; 34:1773-1775 (C) 2008 ASCRS and ESCRS