Iontophoresis versus subcutaneous injection: a comparison of two methods of local anesthesia delivery in children.

The relative efficacy of local lidocaine anesthesia administered by subcutaneous injection and by iontophoresis was studied in 13 pediatric renal dialysis patients (ages 11-19 years: mean age 15.8 years). Each patient served as his own control at 3 assessment periods. Each type of anesthetic delivery method was administered to either of 2 fistula sites. Patients used visual analogue scales to rate pain, anxiety, and satisfaction for each method. Behavioral observations were made by an observer and a nurse. Paired sample t tests were used to compare the 2 drug delivery methods for patient, observer, and nurse ratings across assessment periods. There were no significant differences between methods for ratings of anxiety before or during the procedure. The injection of lidocaine was rated as more painful by the observer and nurse (with a trend for patients) than the use of iontophoresis. But, the patients and nurse rated the injection method as more effective. Iontophoresis was never rated as superior to the injection method, even after turning over control of drug delivery by iontophoresis to the patient (sessions 2 and 3). Patients were more satisfied with iontophoresis at session 2 when they took over control, but lost enthusiasm by session 3. Three subjects withdrew from the study due to cutaneous burns and prolonged anesthesia delivery time with iontophoresis. Iontophoresis appears to be effective in reducing the pain of dialysis needle insertion but requires further investigation before it can be considered a viable alternative to subcutaneous injection.