A comparative study of pain on injection with propofol long-chain triglycerides versus propofol medium/long-chain triglycerides with lignocaine

Background: Propofol long-chain triglyceride (LCT) is the most commonly used intravenous anesthetic drug, which has pain on injection as its major disadvantage. Many drugs have been used to alleviate this pain with variable efficacy, among them lidocaine pretreatment is most popular. Propofol medium-chain triglyceride (MCT)/LCT emulsion has the ability to decrease pain on injection. The availability of propofol with two different formulations necessitates a comparison of pain on injection with lidocaine pretreatment. Aim: The aim of this study was to study the incidence and intensity of pain on injection with propofol LCTs versus propofol MCT/LCTs with lignocaine. Materials and Methods: This prospective, double-blind, and randomized controlled study included 120 American Society of Anesthesiology Grade I and II participants undergoing General Anesthesia. In Group A, patients were induced with 1% propofol LCT (2 mg/kg) with 2% lidocaine 2 ml and in Group B 1% propofol MCT/LCT (2 mg/kg) with 2% lidocaine 2 ml. Assessment of pain on injection was performed after 30% of total induction dose was injected at a rate of 1 ml/s by Verbal Rating Scale. Results: Group A reported an incidence of pain in 28.4% and Group B with 13.3%. There was a statistically significant difference in the incidence and intensity of pain with propofol MCT/LCT along with lignocaine. Sixteen patients in Group A and eight patients in Group B had mild pain, whereas one patient in Group A and none of them in Group B had moderate pain. Conclusion: Premixing lignocaine with MCT/LCT propofol significantly reduces both the incidence and intensity of pain as compared to LCT propofol with lignocaine.