Propofol injection pain: A randomised,controlled trial comparing the effect of local warming and local cooling of injection site

Objective: various drugs and techniques have been proposed in order to prevent propofol induced pain. although warming of propofol and local warming have been reported to be effective in reducing the pain,local cooling has not been studied yet. in this study,we have aimed at studying the effect of local warming and cooling on the pain induced by propofol. method: 120 patients of ages beetween 18-65 undergoing elective surgery were included in this prospective,single-blinded study. patients were randomized into 3 equal groups in group i (control),no intervention was applied,in group ii warming at +40°c,in group iii cooling at +2-4°c was applied for 2 minutes prior to propofol administration at the site of venous access . in each patient,propofol was injected over a period of 1 min at a dose of 2,5 mg/kg. pain scores during propofol injection was recorded using the 5-point verbal rating scale. results: demographic data were comparable between groups 21 of 40 patients in the local warming group,9 in the local cooling group (group iii) and 7 in the control group (group i) had no pain (p=0,006),(p<0,05). there was a significant difference in the number of patients with severe pain between local warming group and control group. in local warming group none of the patients experienced severe pain whereas in the control group,6 patients experienced severe pain (p<0,05). the frequency of pain (with a pain score of 1,2,3 and 4) at propofol injection was lower in group ii (47.5%) compared to group iii (77.5%) and i (82.5%) (p=0.006),(p=<0,001). there was no significant difference in pain between group i and iii. conclusion: application of local warming prior to propofol administration has decreased the pain induced by propofol effectively whereas local cooling had no impact.