Preventive effect of a vapocoolant spray on propofol-induced pain: a prospective, double-blind, randomized study

Propofol causes injection pain. Although lidocaine pre-treatment via venous occlusion is known to be the most effective way, it still has some inconvenience. We implemented this study to compare the effect of a vapocoolant spray with lidocaine pre-treatment.

Participants (n = 90) were randomized to one of three groups. Group V: after placebo injection and tourniquet, the vapocoolant spray was applied; group L: after lidocaine injection and tourniquet, the placebo spray was applied; group C: after placebo injection and tourniquet, the placebo spray was applied. The intensity of propofol-induced pain, the incidence of metallic taste, and the satisfaction were assessed.

Propofol-induced pain was significantly lower in groups V and L than in group C [0.5 (0-2.25), 0.5 (0-1), and 5 (1-7), median (interquartile range), respectively, p < 0.001]. There was no significant difference in pain intensity between groups V and L. Group L showed a significantly higher incidence of metallic taste than groups V and C (23, 0, and 0%, respectively; p = 0.001). Groups V and L showed higher satisfaction scores than group C [5 (4-5), 4 (3.75-5), and 2 (2-3), respectively; p < 0.001], and there was a significant difference between groups V and L (p = 0.012).

Vapocoolant spray showed a similar effect to lidocaine in analgesia and lowered the incidence of a metallic taste. These resulted in greater satisfaction with the vapocoolant spray compared with lidocaine. Vapocoolant spray is an effective and convenient way to prevent propofol-induced pain.