[Use of iontophoretic anesthesia for venipuncture].

The usefulness of iontophoretic anesthesia with 10% lidocaine was evaluated on insertion of venous catheters on 38 blood donors in a blood bank and on 41 patients in a hospital, after the arm was charged for 3, 6 or 9 minutes with 1.5 mA of electricity by using a hand-made iontophoretic anesthesia apparatus. In the blood donor group, the pain-relief effect was observed in 25% of donors after charging for 3 min; in 68% after 6 min; and in 93% after 9 min. In the patient group, anesthesia was observed in 14% of patients after 6 min and in 65% after 9 min though the effect was observed in 81% after 6 min and in 65% after 9 min. But only 45-48% of subjects in both groups requested the anesthesia after charging for either 6 or 9 min. This suggests that the duration for 9 min was not liked by the subject despite the pain on insertion. Therefore it is concluded that the charging duration of the iontophoresis must be shorter for this method to become useful as local anesthesia.