Comparison of the effects of vapocoolant spray and topical anaesthetic cream (lidocaine-prilocaine) on pain of intravenous cannulation: a randomised controlled trial

Objective Intravenous cannulation is a routine procedure in the ED. Different methods are being used to reduce the pain of intravenous cannulation. Among them, there are studies which have shown the efficacy of vapocoolant spray and lidocaine-prilocaine combination topical cream. This study aimed to compare the efficacy of these methods in pain management.Method This was a randomised clinical trial study including adult (18-65 year) patients admitted to the ED of an academic hospital in Iran between February 2024 and May 2024 and who required peripheral intravenous catheter. Patients were assigned randomly to vapocoolant spray or lidocaine-prilocaine cream. The spray was applied for 30 s immediately before intravenous cannulation and the cream 45 min before intravenous cannulation. Patients' pain scores were assessed by Numeric Rating Scale (NRS) immediately after cannulation along with adverse effects. Patients' willingness to use the same anaesthetic method was also recorded.Result This study included 77 patients; median age was 39 (IQR: 29.75-55.39) and 48% were men. The median cannulation pain score was 2 (IQR: 2-3) in the vapocoolant group and 3 (IQR: 2-3) in the lidocaine-prilocaine cream group (p value=0.09). Overall, adverse events occurred in 24 (31%) patients; 21 patients in the lidocaine-prilocaine group experienced transient paleness (p value=0.03). 33 (43%) patients who received vapocoolant and 21 (27%) patients who used the cream selected to use their assigned method again (p value=0.02).Conclusion This study demonstrated that the vapocoolant spray was not statistically more effective than lidocaine-prilocaine cream in pain reduction during intravenous cannulation. Although all these side effects were generally considered clinically insignificant, the spray group exhibited significantly fewer side effects compared with the cream group.Trial registration number NCT04473820.