Comparison of intravenous dexmedetomidine and intravenous lignocaine for the prevention of conventional propofol injection pain: A prospective randomised double-blind study

Abstract

Background: Pain on injection with propofol is a well recognized problem sometimes very distressing to patient. Current study compared the effectiveness of intravenous dexmedetomidine and lignocaine pretreatment for the prevention of propofol pain during induction of general anaesthesia. Methods: Ninety, American Society of Anesthesiologists (ASA) grade I and II patients were randomised into three groups of 30 each, Group D, Group L and Group N. Group D, patients received dexmedetomidine 0.2 μg/kg diluted to 5 ml of normal saline, group L, patients received 0.5 mg/kg preservative free lignocaine diluted to 5 ml of normal saline and group N, patients received 5 ml of normal saline. Intravenous access was secured with 20 G cannula and venous occlusion was applied to forearm using a pneumatic tourniquet inflated to 90 mm of Hg for 1 minute. The study drugs were injected over 5 seconds and after 1 minute venous occlusion was released and 25% of total calculated dose of propofol (2 mg/kg) was given intravenously over a period of 60 seconds. Severity of pain was evaluated using McCrirrick and Hunter scale at 0 seconds, 30 seconds and 60 seconds respectively and then remaining propofol and neuromuscular blocking agent was given. Results: The groups were comparable demographically. There was significant difference in pain scores assessed at 0 seconds, 30 seconds and at 60 seconds between the three groups. Conclusions: Dexmedetomidine in a dose of 0.2 μg/kg before applying venous occlusion by tourniquet for one minute in the same vein before inducing the patient with propofol was effective in decreasing the propofol injection pain when compared to lignocaine in a dosage of 0.5 mg/kg and placebo.