Dilution of a mepivacaine-adrenaline solution in isotonic sodium bicarbonate for reducing subcutaneous infiltration pain in ambulatory phlebectomy procedures: a randomized, double-blind, controlled trial.

ABSTRACT

BACKGROUND: Varicose veins are treated under local infiltration anesthesia. Literature shows that adding sodium bicarbonate reduces the pain associated with local infiltration anesthesia. Nonetheless, sodium bicarbonate is underused. OBJECTIVE: We sought to assess if the use of a solution of mepivacaine 2% plus adrenaline with sodium bicarbonate 1.4% results in less pain associated with local infiltration anesthesia preceding ambulatory phlebectomies, compared with standard preparation diluted with normal saline. METHODS: In all, 100 adult patients undergoing scheduled ambulatory phlebectomy were randomized to receive either a solution of mepivacaine chlorhydrate 2% plus adrenaline in sodium bicarbonate 1.4% or a similar solution diluted in normal saline 0.9%. RESULTS: Median pain scores associated with local infiltration anesthesia reported in the intervention and control groups were 2 (SD=1.6) and 5 (SD=2.0) (P<.0001), respectively. A general linear model with bootstrapped confidence intervals showed that using the alkalinized solution would lead to a reduction in pain rating of about 3 points. LIMITATIONS: Patients were not asked to distinguish the pain of the needle stick from the pain of the infiltration. Moreover, a complete clinical study of sensitivity on the infiltrated area was not conducted. CONCLUSIONS: Data obtained from this study may contribute to improve local infiltration anesthesia in ambulatory phlebectomy and other phlebologic procedures.