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

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. 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. 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%. 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. 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. Data obtained from this study may contribute to improve local infiltration anesthesia in ambulatory phlebectomy and other phlebologic procedures.