Prospective comparison between buffered 1% lidocaine-epinephrine and skin cooling in reducing the pain of local anesthetic infiltration.

BACKGROUND: Pain associated with the infiltration of local anesthesia is attributed to the acidity of the solution. Buffering with sodium bicarbonate has been used widely to reduce this affect. Growing evidence supports skin cooling (cryoanalgesia) as a measure to reduce infiltration pain.

OBJECTIVE: To compare the effect of 1% lidocaine-epinephrine [1:100,000] buffered with sodium bicarbonate with skin cooling for 2 minutes with ice in reducing the pain of infiltration of anesthetic solution.

METHODS AND MATERIALS: Sixty healthy volunteers were recruited for this prospective study. Each subject received an intradermal injection of buffered solution in one arm and injection of unbuffered solution after ice application in the other arm. Immediately after each injection, subjects rated pain of infiltration on a 100-mm visual analog scale. Pain scores were compared using the paired t-test.

RESULTS: Sixty percent of subjects reported that pain of infiltration was greater after skin cooling than with buffered solution. Mean ± standard deviation pain scores were 24.8 ± 21.7 for skin cooling and 21.1 ± 20.8 for buffered solution; this difference was not statistically significant.

CONCLUSION: There is no significant difference between buffered anesthetic solution (buffering) and skin cooling in reducing the pain of infiltration of 1% lidocaine - epinephrine.