The pain reduction efficacy of granisetron, dexmedetomidine and lidocaine after etomidate injection for surgery under general anaesthesia

Abstract

Introduction: Pain on injection of anaesthetics is significant for patients' dissatisfaction. The present study aimed to compare the efficacy of granisetron, dexmedetomidine and lidocaine on the reduction of etomidate injection pain. Materials and Methods: A clinical trial was performed on 132 patients aged 18–50 years undergoing elective surgery under general anaesthesia. Two cannulas were inserted into the veins on the dorsum of both hands, and arterial drainage of both was occluded. The patients were randomised into three groups and injected with 6 mg granisetron, 40 mg lidocaine and 5 mcg dexmedetomidine, respectively, into one arm, while injecting normal saline into the other arm. Two minutes later, the tourniquet was released in each group, and 2 mg etomidate was injected into each arm. Participants were asked to rate their pain using the visual analogue scale for each arm on injection, as well as 5 min after injection. Results: A significant difference was found in pain scores of etomidate injection in the three groups of dexmedetomidine, lidocaine and granisetron. Moreover, the pain reduction effect was lower both immediately and at 5 min after injection in dexmedetomidine group than other groups (P = 0.03). In addition, the mean of pain score was lower in lidocaine group than granisetron group (P = 0.01). Nevertheless, the trend of haemodynamic parameters was not significant and different among studied groups (P > 0.05). Conclusion: Dexmedetomidine seems to have been more efficient than the others in reducing etomidate injection pain. However, the adverse effect of the three interventions was not different, and the haemodynamic parameters were stable during anaesthesia.