Comparison of the effects of lidocaine pre-administration and local warming of the intravenous access site on propofol injection pain: Randomized, double-blind controlled trial.

BACKGROUND: Lidocaine reduces pain that occurs upon the intravenous injection of propofol. But, there are few non-pharmacological nursing interventions to reduce propofol injection pain.

OBJECTIVE: To compare the effects of lidocaine pre-administration and local warming of the intravenous access site on propofol injection pain.

DESIGN: Prospective, double-blind, randomized controlled trial.

SETTING: The 555 bed, non-teaching National Cancer Center in Kyunggido, South Korea.

PARTICIPANTS: A total of 96 patients who underwent thyroidectomy under total intravenous general anesthesia with propofol were randomly allocated to the control, lidocaine pre-administration (LA) or local warming (LW) group.

METHODS: All three groups received 2% propofol with an effect-site target at 3μg/mL for induction dose. The control group received 2% propofol with no intervention. The lidocaine pre-administration group received 2% propofol 30s after 1% lidocaine 30mg. The local warming group received 2% propofol after warming of the intravenous access site for 1min using 43°C forced air. Propofol injection pain was assessed by four-point verbal categorial scoring (VCS), numerical rating scale (NRS) and surgical pleth index (SPI).

RESULTS: Pain VCS of the LA group (mean±SD, 1.11±0.45) was significantly reduced (U=-3.92, p<.001) compared to the control group (mean±SD, 1.71±0.74). Pain VCS of the LW group (mean±SD, 0.76±0.44) was significantly reduced (U=-5.17, p<.001) compared to the control group (mean±SD, 1.71±0.74). Pain VCS of the LW group was significantly reduced compared to the LA group (U=-3.33, p=.001]. Pain NRS of the LA group (mean±SD, 4.31±2.32) was significantly reduced (mean difference, 1.82; 95% CI, 0.63-3.00; p=.003) compared to the control group (mean±SD, 6.13±2.39). Pain NRS of the LW group (mean±SD, 3.06±2.37) was significantly reduced (mean difference, 3.07; 95% CI, 1.63-4.51; p<.009) compared to the control group. There were significant differences in pain NRS between the LA group and the LW group (mean difference, 1.25; 95% CI, 0.09-2.42; p=.035). SPI of the LA group (mean±SD, 64.1±16.3) was significantly reduced (mean difference control versus LA, 8.36; 95% CI, 1.64-15.1; p=.016) compared to the control group (mean±SD, 72.5±9.56). SPI of the LW group (mean±SD, 55.0±16.2) was significantly reduced (mean difference control versus LW, 17.4; 95% CI, 10.8-24.0; p<.001) compared to the control group. There was a significant difference in SPI between the LA group and LW group (mean difference, 9.06; 95% CI, 1.02-17.1; p=.028).

CONCLUSION: Local warming of the intravenous access site by 43°C forced air for 1min is slightly more effective in reducing propofol injection pain compared to lidocaine pre-administration.