The effect of local cooling on pain perception during infiltration of local anaesthetic agents, a prospective randomised controlled trial.

The effect of pre-infiltration local cooling of the site of inguinal herniorrhaphy on pain perception during infiltration of local anaesthetic was studied in a prospective randomised controlled trial. One hundred patients were randomly allocated to receive topical application of either a cooled saline bag (study group) or a saline bag at room temperature (control group) prior to injection of local anaesthetic. Pain scores were recorded using a visual analogue scale following application of the saline bags and again on completion of infiltration with local anaesthetic. There was no significant difference in pain scores following topical saline bag application. However, a highly significant difference (p = 0.0001, Mann-Whitney U) was observed between post-infiltration pain scores of the study group (median = 2) and the control group (median = 6).