Written by Megan Hilbert
Vapocoolant spray improved pain from digital blocks for repair of finger injuries.
Why does this matter?
Digital blocks can be both painful and anxiety-provoking for patients. Vapocoolant sprays have been shown to benefit other minor procedures including intravenous cannulation and vaccination – so why not extends its use?
“Oh look, I’ve been impaled” – Olaf from Frozen
Advantages of vapocoolant sprays include that they are fast acting and topical. The active ingredient (ethyl chloride) rapidly evaporates, cooling the skin, but also affects local ion channels, effectively slowing conduction of unmyelinated nerve fibers.
This was a prospective, randomized study aimed at evaluating the effectiveness of vapocoolant spray to reduce pain associated with digital blocks. Patients were randomized into the control or spray-treated groups. The spray-treated group was further subdivided into unilateral and bilateral treatment. All digital blocks were completed with a 27 gauge needle and 1% lidocaine without epinephrine. Providers completing the block were blinded to the randomization. Primary endpoints included visual analog scale (VAS) estimation of pain both during penetration of the needle and infiltration of the local anesthetic as well as evaluation of statistically significant change in pain.
Results showed a statistically significant lower pain score during penetration and infiltration in the spray groups as compared to the control (p<0.001). It also showed a statistically significant pain change during penetration for the bilateral spray-treated group (p<0.001), but not the unilateral spray-treated group (p-0.312); suggesting that if you are going to spray, do so on both sides of the finger. It’s an easy enough intervention that you can add to your toolbox. So next time you go to do a digital block – FREEZE – and take a moment to find some “magic spray.”
Editor’s note: The study protocol for applying vapocoolant involved watching for blanching of the skin. It seems unlikely the physician performing the block remained blinded, and breaches in blinding were not assessed by the authors. ~Nick Zelt
Evaluation of vapocoolant spray effect on pain reduction during digital nerve block: A randomized clinical trial. Am J Emerg Med. 2021 Dec;50:260-263. doi: 10.1016/j.ajem.2021.08.001. Epub 2021 Aug 6.