Abstract
Purpose: :
Topical gel anesthesia is gaining popularity for intravitreal injections and cataract surgery, but a potential risk exists in the gel’s physical ability to shield bacteria from povidone-iodine’s antiseptic action. The purpose of this project is to determine if application of 5% povidone-iodine solution prior to 2% lidocaine gel reduces bacterial growth to a degree comparable to application of povidone-iodine alone, and to determine if application of povidone-iodine for 5 seconds prior to lidocaine gel reduces bacterial growth to a degree comparable to application for 30 seconds.
Methods: :
Blood agar plates inoculated with Staphylococcus epidermidis were prepared using 2% lidocaine gel and 5% povidone-iodine solution in 8 groups as follows: 1) no treatment; 2) application of lidocaine gel; 3) application of lidocaine gel, followed by povidone-iodine for 30 seconds; 4) application of lidocaine gel, followed by povidone-iodine for 5 seconds; 5) application of povidone-iodine for 30 seconds; 6) application of povidone-iodine for 5 seconds; 7) application of povidone-iodine for 30 seconds, followed by lidocaine gel; 8) application of povidone-iodine for 5 seconds, followed by lidocaine gel. The plates were then incubated at 37 degrees Celsius for 24 hours, and the bacterial growth was determined by two graders.
Results: :
Plates on which lidocaine gel was applied alone or prior to povidone-iodine had no statistically significant difference in bacterial counts compared to plates without any treatment (p=0.553 and p=0.485, respectively). Plates on which povidone-iodine was applied alone or prior to lidocaine gel demonstrated no bacterial growth, regardless of whether the antiseptic was retained on the plate for 5 seconds or for 30 seconds.
Conclusions: :
Povidone-iodine is effective at reducing bacterial counts when applied prior to lidocaine gel, regardless of whether the antiseptic has been present for 30 seconds or for just 5 seconds prior to administration of the anesthetic. Lidocaine gel was confirmed to be a barrier to antisepsis when administered prior to povidone-iodine.
Keywords: endophthalmitis • bacterial disease