Double-blind, bilateral pain comparison with simultaneous injection of 2% lidocaine versus buffered 2% lidocaine for periocular anesthesia.

Abstract

Determine if raising the pH of 2% lidocaine with epinephrine 1:100 000 to a physiologic level decreases pain perception during periocular, subcutaneous anesthesia. Double-blind, prospective, randomized study. Simultaneous unilateral injections of buffered and unbuffered lidocaine solutions were given before surgery to patients having bilateral, periocular surgery. Fifty-four consecutive patients (27 male and 27 female; mean age, 68 years; standard deviation, 11 years). Patients were given simultaneous injections of buffered and unbuffered 2% lidocaine with epinephrine 1:100 000. The needles were inserted simultaneously and the anesthesia was injected for a 20-second count for a total volume of 1.0 ml per injected side. After the simultaneous injections, the patients were asked to rate the pain on each side on a Likert-type visual analog scale of 0 to 10. Sixty-five percent of patients preferred the buffered lidocaine with a scaled pain reduction of 0.9 (P = 0.0005). Additionally, for the patients who believed that the buffered solution was less painful, the mean decrease in scaled pain rating was 2, for a 51% reduction in pain level (P = 0.001). No gender differences were noted. Buffering 2% lidocaine with epinephrine 1:100 000 with sodium bicarbonate 8.4% offers a clinically and statistically significant reduction in pain experienced by two-thirds of patients receiving periocular subcutaneous anesthesia.