Volume of 4% sodium bicarbonate required to remove pain in tumescent anaesthesia for endovenous laser ablation of saphenous veins: a randomized, double-blind, controlled trial

Background: Sodium bicarbonate in tumescent anaesthesia for endovenous laser ablation (EVLA) of saphenous varicose veins is underused. Objective: To find the volume of 4% sodium bicarbonate required to significantly reduce intraprocedural pain. Methods: Tumescent solution ingredients were determined by recalculating concentrations based on the Klein solution and was titrated to a slightly alkaline pH by buffering with 4% sodium bicarbonate. The outcome variable was the level of intraprocedural pain measured with a visual analogue scale. Results: In total, 74 patients undergoing EVLA were randomized to receive either buffered solution at pH 7.1 (group A) or buffered solution at pH 6.63 (group B). Median pain scores (interquartile range) were significantly lower in patient group A than in group B (0.65 (0.2-1.38) versus 1.65 (0.87-3.5), p