Dexmedetomidine Versus Ketamine Pretreatment to Alleviate Propofol Injection Pain: A Randomized and Blinded Study

Abstract

Background: Both ketamine and dexmedetomidine have proven effective in relieving the pain resulting from propofol injection. However, studies comparing them directly are limited. The primary outcome was to compare the incidence of propofol injection pain after dexmedetomidine pretreatment with ketamine pretreatment. Secondary outcome was to study the changes of haemodynamic parameters that arise after the administration of the pretreatment drug till anaesthesia was induced with propofol.
 Methods: In this randomized, triple blinded, parallel arm single centre study, we compared pre-treatment with dexmedetomidine 0.5mcg/kg (Group A) and ketamine 0.5mg/kg (Group B). Our primary objective was to compare the incidence of propofol injection pain. The McCririck and Hunter scale was used to evaluate the pain. Secondarily, we compared the changes of haemodynamic parameters that arose after the administration of the pre-treatment drug till induction of anaesthesia with propofol.
 Results: Among 168 patients evaluated for eligibility, 140 were included for final analysis with 70 patients in each group. The incidence of propofol injection pain in Group A was 74.3% (52/70) and that in Group B was 42.9% (30/70) (p value <0.001). No pain was reported by 25.7% (18/70) and 57.1% (40/70) patients in Group A and B respectively. Mild and moderate to severe pain was experienced by 58.6% and 15.7% patients in Group A, where as it was 40% and 2.9% patients in Group B respectively.
 Conclusion: Ketamine leads to a greater reduction in both the frequency and intensity of pain resulting from propofol injection when compared to dexmedetomidine.