Effects of fentanyl and lignocaine on propofol injection pain: a randomized, placebo-controlled double-blind study

Background: Pain on intravenous injection of propofol (PIP) is a well-known drawback and is still a limitation of this otherwise excellent IV anaesthetic agent. Efforts are underway to reduce the incidence and severity of this pain.
Aims and objectives: To compare the efficacy of fentanyl with lignocaine in reducing the incidence and severity of PIP.
Materials and Methods: Ninety patients of ASA grade I and II, aged 18-60 yrs, weight 40-80 kg, scheduled for elective surgery under general anaesthesia were randomly allocated to one of the three groups (n=30). Each patient received 2 ml of pretreatment solution over a period of 5 seconds followed one minute later by injection of propofol mixture at a rate of 2.5 ml every 5 seconds until loss of consciousness. Group L (Lignocaine): Pretreatment with 2 ml NS; propofol mixture:10 ml of 1% propofol and 2 ml of 2% lignocaine (40mg). Group F (Fentanyl): Pretreatment with 2 ml fentanyl (100g); propofol mixture: 10 ml of 1%propofol and 2 ml NS. Group P(Placebo): Pretreatment with2 ml NS; propofol mixture: 10 ml of 1% propofol and 2 ml NS. Pain during injection of propofol mixture and pretreatment solution were assessed and graded as mild, moderate or severe. Heart rate and BP were monitored before laryngoscopy and 1, 2 and 5 minutes after laryngoscopy and every 15 minutes thereafter. The data were represented as frequencies and meanSD and statistical analysis was done using SPSS Version 15.0. Confidence level of the study was kept at 95%; hence a "p" value <0.05 was considered as statistically significant.
Results: The incidence of pain was 33.33% in Group L, 36.67% in Group F and 80%in Group P. Pain score was significantly lower in Group L and Group F as compared with Group P (p<0.001). However, there was no statistically significant difference in pain scores between Group L and Group F (p=0.713). Incidence of recall of pain was significantly higher in Group P when compared with Group L (p=0.024) and Group F (p=0.002). However, no significant difference was seen between Group L and Group F (p=0.407). There were no significant haemodynamic changes warranting any medical or surgical intervention in any of the groups.
Conclusion: We conclude that fentanyl can prove to be a better alternative than lignocaine for the prevention of PIP because it has an added advantage of providing intra and post operative analgesia and a stable haemodynamics.