Nitrous Oxide Reduces Pain Associated With Local Anesthetic Injections.

BACKGROUND

Local anesthetic injections can be painful and distressing.

OBJECTIVE

The aim of this study was to determine whether nitrous oxide, ice, vibration, or topical anesthetic improves analgesia for local anesthetic injections.

METHOD: A cohort study of 400 patients undergoing Mohs micrographic surgery with local anesthetic was conducted. Patients received no intervention (n = 200), ice (n = 50), topical anesthetic cream (n = 50), vibration device (n = 50), or nitrous oxide (n = 50). Pain was rated using the Visual Analogue Scale (VAS) and Wong-Baker FACES Pain Rating Scale.

RESULTS

Without intervention, mean VAS was 4.2 and FACES was 4.6. Nitrous oxide was the most successful in reducing pain (mean VAS 1.6 vs. 4.2, P < .01, FACES 1.2 vs. 4.6, P < .01). Topical ice reduced pain (mean VAS 3.0 vs. 4.2, P < .01, FACES 3.0 vs. 4.6, P < .01). Vibration reduced pain (mean VAS 3.5 vs. 4.2, P < .01, FACES 3.6 vs. 4.6, P < .01). Higher pain scores were associated with age <50 (P = .02), male sex (P = .05), and surgery on the nose, lip, ear, or eyelid (P = .02).

CONCLUSION

Nitrous oxide, ice, and vibration reduce injection pain. These interventions are especially useful for younger males undergoing surgery on the nose, lip, ear, or eyelid.