ABSTRACT Objective: To determine whether topical lidocaine attenuates the pain of buffered lidocaine infiltration. Methods: This was a prospective, randomized, double‐blind, placebo‐controlled trial conducted at a university‐based ED. The subjects were adults who had lacerations being repaired using local anesthesia. Two 0.5‐mL injections of buffered lidocaine were given in a standardized manner. The first was given prior to application of topical study solution. The second was given on the opposite side of the laceration after topical application of study solution, which was 5 mL of either 2% lidocaine or saline placebo. The pain of each infiltration was measured using a visual analog pain scale. Pain scores were calculated and compared using a Wilcoxon test with significance defined as p 0.05. Results: A total of 54 subjects participated; 29 received lidocaine topically and 25 received placebo. The groups were similar with respect to age, gender, wound length, wound location, and initial pain score. Pain scores decreased by 11.6 ± 18.6 mm for lidocaine and 10.9 ± 20.9 mm for placebo (p > 0.5). The study had the power to detect a 15‐mm pain score difference (α = 0.05 and β = 0.20) on a 100‐mm scale. Conclusion: Topical 2% lidocaine does not attenuate the pain of infiltration of buffered lidocaine more than does topical normal saline. Investigation of other topical anesthetics with and without epinephrine in conjunction with buffered lidocaine is warranted.
ABSTRACT Objective: To compare the pains of infiltration of a local anesthetic for simple lacerations when used from within the wound vs through intact skin. Methods: A randomized, prospective, single‐blind, experimental protocol was conducted on a convenience sample of adults with simple lacerations. Subjects received two 0.5‐mL injections of buffered lidocaine in each of the sites being compared. Immediately following each injection, pain was measured using a visual analog pain scale. Pain scores were converted to a numerical score and analyzed by a Wilcoxon signed‐rank test. Subjects also were asked which injection hurt more, the first or the second (analyzed by a x 2 test). Results: A total of 63 subjects were enrolled. The first injection was within the wound and the second injection through intact skin (group 1) for 32 patients, and the order was reversed for 31 patients (group 2). Median pain scores for all inside‐the‐wound injections (14 mm) were lower than those with intact skin injections (37 mm; p < 0.0001). In group 1, 4 subjects reported the first injection (within wound) hurt most, 23 thought the second (intact skin) hurt most, and 5 found no difference. In group 2, 18 subjects reported the first injection (intact skin) hurt most, 5 believed the second injection (within wound) hurt most, and 8 found no difference, p < 0.0001. Conclusion: Local anesthesia is less painful when injected from within a laceration as compared with intact skin.
