No antiinflammatory effect of short-term topical and subcutaneous administration of local anesthetics on postburn inflammation.

BACKGROUND AND OBJECTIVES. To investigate the effect of topical and subcutaneous administration of local anesthetics on the inflammatory response to thermal injury in human volunteers. METHODS. Sixteen healthy volunteers received identical burn injuries (49 degrees C for 6 minutes) on the right and left calves with a 15 x 25 mm rectangular thermode. Eight subjects had topical 5% EMLA applied before and after burn injury, and another eight subjects were administered subcutaneous 0.5% bupivacaine infiltration before burn injury on the right or left leg. No treatment was applied to the contralateral leg in either group because this served as the control. The dermal response after burn injury in test areas with EMLA or bupivacaine and without treatment was compared 24 hours, 72 hours, 168 hours, and 14 days after burn injury. RESULTS. No significant difference was found in the area of flare, development of blister and ulcerations, or the intensity of inflammation after burn injury between the control legs and EMLA- or bupivacaine-treated legs, respectively. CONCLUSION. No antiinflammatory effect of short-term preinjury and postinjury topical 5% EMLA or subcutaneous 0.5% bupivacaine could be demonstrated after thermal injury in human volunteers.