Intravenous ketamine attenuates injection pain and arterial pressure changes during the induction of anesthesia with propofol: a comparison with lidocaine.

OBJECTIVE

To compare the effects of lidocaine and ketamine pretreatment on injection pain and hypotension due to propofol induction.

DESIGN

Double blinded randomized controlled clinical trial. Place and Duration of the Study: Department of Anesthesiology, Surgical Intensive Care Unit and Pain Management, Dow University of Health Sciences and Civil Hospital, Karachi from February 2005 to December 2005.

PATIENTS AND METHODS

One hundred patients, age 20-60 years, of either gender, ASA I and II scheduled for elective gynaecological, urological, orthopedic or general surgical procedures under general anesthesia were randomly allocated into two groups i.e. group A to receive ketamine 0.5 mg/kg in volume of 2 ml with venous occlusion and group B to receive 2 ml of 1% lidocaine with venous occlusion as pretreatment before propofol induction. Venous occlusion was performed using rubber tourniquet after elevating the arm for 30 seconds, which was released 60 seconds after giving the pretreatment bolus and anesthesia was induced with propofol (2 mg/ml). Fifteen seconds after injection of 25%, the calculated dose of propofol and severity of injection pain was evaluated. Heart rate (HR) and noninvasive blood pressure were recorded pre-operatively, just before propofol induction, after propofol induction, immediately after intubation and 3 minutes after intubation.

RESULTS

Comparing the lidocaine group, the intensity and incidence of pain after propofol injection was lower in ketamine group but remained statistically insignificant. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were significantly higher in ketamine group after induction with propofol. The maximum fall in SBP from baseline in ketamine group was 16% and 29.1% in lidocaine group, while maximum decrease in DBP in ketamine group was found to be12.66% vs. 26.47% in lidocaine group. There was no significant change in heart rate from baseline in either group.

CONCLUSION

Ketamine pre-treatment with venous occlusion is an effective method in reducing pain and providing hemodynamic stability after propofol induction.