REDUCING THE PAIN OF LOCAL-ANESTHETIC INFILTRATION - WARMING AND BUFFERING HAVE A SYNERGISTIC EFFECT

Study objective: To compare room-temperature unbuffered lidocaine, war m lidocaine, buffered lidocaine, and warm buffered lidocaine to determ ine which of the four solutions is least painful during infiltration. Design: Randomized, controlled, double-blinded, volunteer study. Type of participant: Thirty-two young healthy adults. Main results: Each su bject received four subcutaneous injections of 1 % lidocaine: room-tem perature unbuffered, warm, buffered, and warm buffered. After each inj ection, participants recorded their perception of pain associated with infiltration of the solution on a visual analog scale. Mean pain scor es for the four solutions were determined and analyzed. The mean perce ived pain score for the warm buffered solution was significantly lower than for any of the other solutions (versus warm: P = .0005; versus b uffered: P = .0028; versus mom temperature: P = .0001). There was no s tatistically significant difference between either the warm solution o r buffered solution and the room-temperature unbuffered lidocaine. The difference in mean pain score for the warm buffered solution, compare d with those for the warm, buffered, and room-temperature solutions, s uggests that warming and buffering have a synergistic effect. Conclusi on: Skin infiltration with warm buffered lidocaine is significantly le ss painful than infiltration with room-temperature unbuffered lidocain e, warm lidocaine, or buffered lidocaine.