The effects of lidocaine anesthesia via lontophoresis on laceration wound healing in a guinea pig model

Abstract

0 The Effects of tidocaine Anesthesia via Iontophoresis on Laceration Wound Healing in a Guinea Pig Model AA Ernst, J Pomerantz, TG Nick, M Landry, J Limbaugh/Louisiana State University Departments of Medicine and Pathology, Section of Emergency Medicine; University of Mississippi School of Allied Health Professions Study background: Iontophoresis is a painless technique for topical anesthesia that uses an electric field to drive charged ions across an epithelial surface. Although it has been used successfully for intact skin, the safety of this technique for laceration repair has never been demonstrated. Study ol~lective: To investigate the effect of iontophoretic fields on rapidly proliferating cells involved in healing of laceration wounds. Design: Prospective, single-blinded animal study using a guinea pig model. Participants: Twelve adult albino guinea pigs. Intervention: Each of the 12 guinea pigs received four induced uncontaminated lacerations. Guinea pigs were nmdomized to groups receiving treatment with lidocaine via iontophoresis, injected lidocainc or half treatment and half control. Aftcr anesthelic treatment, wounds were repaired in as tan dard fashion. The wounds were examined grossly on a daily basis, and on the tenth day the incised skin containing the laceration was examined by a pat hologist blinded to treatment group Measurements and main resuhs: Forty-eight wounds were assessed for wound healing--24 receivcd lidocame via iontophoresis, and 24 received lidocaine via injection. No clinical or histologic evidence of int~:ction or necrosis was present in any wound. The power of the study to determine a 40% difference between the two groups was 0.8. There was significantly more gl-anu[oma and granulation tissue formation in the iontophoresis group than in the irtiected lidocaine control group (P = .0004 Fisher's exact test). -I'herc was no statistically significant differences in the degree of inflammation between the two groups as measured by amount of dermal fibrosis (P =. [4 Fisher's exact test), giant cell Iormation (P = .21, Fisher's exact test), and presence of acute and/or chronic inl]ammation (P = .17, Wilcoxon rank-sum test). Wound healing proceeded normally with 100% in both groups having normal scar formauon and healing at ten days. Conc]usion: lontophoresis appears to be a safe method of anesthesia delivery in this guinea pig model with lacerations. Increased granuloma and granulation tissue formation may indicate an enhancement of wound healing via ionmphoresis. Further study of the safety and efficacy of anesthesia dehvery via this method is needed.