Abstract
Topical anesthesia in the form of TAC (tetracaine, adrenaline, cocaine) solution has been used for wound repair. This pilot study was designed to determine if the topical anesthesia achieved using a mixture of lidocaine (5%) and epinephrine (1:2000) (TLE) is equivalent to the topical anesthesia obtained using a solution of tetracaine (0.5%), epinephrine (1:2000), and cocaine (10.4%) (TAC). A prospective, randomized, doubleblind trial was carried out from May 1992 to August 1992 at a community-based teaching hospital Emergency Department (ED) that receives 50,000 annual visits. Patients with facial or scalp lacerations suitable for topical anesthesia presenting to the ED were included when study physicians were in attendance. Exclusion criteria included the presence of a sensory altering substance (eg, ethanol), age younger than two years, hypertension, pregnancy, allergy to any of the study's pharmacological agents, wounds greater than six hours old, grossly contaminated wounds, and wounds longer than six centimeters. Either a TAC or TLE solution was applied to lacerations before suturing. The laceration was repaired and the patient or physician evaluated the degree of pain from the procedure by using a standardized visual pain scale. A total of 35 patients were studied. Seventeen patients were in the TLE group; 18 in the TAC group. The mean ages were compared and found to be similar (P = .40) between the two test groups. The pain scale values, the diameter of tissue blanch around laceration (halo size), and the time to laceration repair from the onset of application of anesthetic were compared and no difference was shown between the TAC and TLE groups. The correlation between the pain scores and the halo size was determined. In the TLE group, a small halo size was associated with a higher pain scale score; in the TAC group this correlation was not apparent. TLE is equivalent to TAC in many respects, especially in producing topical anesthesia. In an average month, 4.6% of the patients seen in the ED of the study site have facial and scalp lacerations amenable to topical anesthesia. The annual cost savings from using TLE instead of TAC is estimated to be $60,000 at the institution studied. The TLE solution also eliminates the potential toxicity from cocaine and tetracaine. © 1995.