Effectiveness of Different Techniques of Ethyl Chloride Spray for Venepuncture-Induced Pain: A Randomised Controlled Trial

BACKGROUND: Venepuncture is an essential component of anaesthesia services. However, this invites pain generating the first negative experience with anaesthesia. Hence, relief of this pain carries considerable importance. Efficacy of ethyl chloride spray although studied, there is no consensus for the best way of application. OBJECTIVES: The present study was conducted to find an effective technique/method of ethyl chloride spray application to reduce venepuncture pain. METHODS: Adult patients posted for different anaesthesia procedures were randomised into three groups. Venepuncture was done either after installation of distilled water or spray of ethyl chloride either once to twice. Venepuncture pain was assessed with a 0-100 Numeric Rating Scale. RESULTS: The analysis showed significant differences among the groups (F [2,96] = 66.27, P < 0.05). The twice sprayed group experienced the least pain ([mean ± standard deviation [SD]] 16.67 ± 10.21), lower in the once spray group ([mean ± SD] 27.58 ± 13.24), and the controls had the highest pain score ([mean ± SD] 49.09 ± 11.28). Post hoc Tukey's tests showed all the three groups differed significantly. The effect size was large, and the variability of the spray on the reduction of pain scores is 58% (η(2) = 57.99). CONCLUSION: Ethyl chloride spray effectively reduces the pain on venepuncture, especially when the vapocoolant is sprayed twice each over 5 s, and from a distance of 5 cm perpendicular to the skin.