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

Abstract

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<0.01). Conclusions: These results show that tumescent anesthesia for EVLA of saphenous veins is less painful if the local anesthetic is buffered prior to its infiltration. Nonetheless, the buffering may be inadequate. We advise adding 143 mL of 4% sodium bicarbonate to 1000 mL 0.08% lidocaine so that the pH of the solution is increased to 7.1 and the intraprocedural pain is reduced significantly.