[Ethyl chloride aerosol spray for local anesthesia before arterial puncture: randomized placebo-controlled trial].

Objectives: To compare the efficacy of an ethyl chloride aerosol spray to a placebo spray applied in the emergency department to the skin to reduce pain from arterial puncture for blood gas analysis.

Material And Methods: Single-blind, randomized placebo-controlled trial in an emergency department of Hospital de Basurto in Bilbao, Spain. We included 126 patients for whom arterial blood gas analysis had been ordered. They were randomly assigned to receive application of the experimental ethyl chloride spray (n=66) or a placebo aerosol spray of a solution of alcohol in water (n=60). The assigned spray was applied just before arterial puncture. The main outcome variable was pain intensity reported on an 11-point numeric rating scale.

Results: The median (interquartile range) pain level was 2 (1-5) in the experimental arm and 2 (1-4.5) in the placebo arm (P=.72).

Conclusion: Topical application of an ethyl chloride spray did not reduce pain caused by arterial puncture.