Effect of lignocaine versus sodium bicarbonate on reducing pain due to intravenous injection of propofol: a prospective randomised double-blinded, controlled study

Context Propofol is the most commonly used intravenous (IV) anesthetic drug for induction of anaesthesia and for sedation, but pain which occur during its injection still remains a problem. Approximately 70 to 90% of patients who receive propofol for anaesthesia induction experience pain during injection and this pain can be quite severe. The most frequently used drug to alleviate pain in propofol injection is IV Lignocaine which acts through the local anesthetic effect on the veins. Administration of sodium bicarbonate with lidocaine was proved to reduce pain in propofol injection through increasing sodium ions concentration as well as increasing serum pH through its buffering effect. Aims To compare the effect of adding lignocaine vs sodium bicarbonate to propofol in reducing pain on propofol injection. Settings and design A randomized, controlled, double-blinded trial. Methods and material One hundred and eighty patients underwent conscious sedation during surgical procedures were randomly divided into three equal groups as follows: Group (L) 3 ml (60 mg) of lignocaine 2% premixed with propofol, group (B) 3 ml of sodium bicarbonate 8.5% premixed with propofol and group (S) 3 ml of normal saline premixed with propofol. The 3 groups were compared regarding pain intensity immediately after IV injection of propofol using the four-point verbal rating and BP. Results The incidence of pain and the pain score were significantly lower in the lignocaine group (43%) in comparison to both group (Saline 81% and bicarbonate 71%) P value < 0.001. However, no difference in pain score or the incidence of pain were found between Group S and Group B. Conclusions Our study demonstrated that mixing lignocaine with propofol appears to be effective in reducing both the incidence and severity of the pain during propofol injection when compared to mixing propofol with sodium bicarbonate or normal saline.