Is Ethyl Chloride Spray Sterile?

Ethyl chloride spray — which is labeled as “nonsterile” by manufacturers — is sometimes used to anesthetize skin before joint injections. In this study, researchers sought to determine whether the spray introduces any bacterial contamination.

At four common injection sites in each of 15 volunteers (shoulders and knees bilaterally; 60 sites total), researchers performed the following sequence in rapid succession. First, they cultured the skin site before any topical application. Second, they swabbed the site with alcohol (as if preparing for arthrocentesis) and cultured the skin again. Third, they sprayed the site with ethyl chloride (using bottles that had been opened and used previously) and cultured the skin yet a third time.

Cultures obtai…