Vapocoolant spray reduces pain scores by Cohen's d -0.30 to -0.48 in critically ill adults during arterial punctureA cold spray eases pain during blood draws for critically ill patients

OBJECTIVES: Critically ill adult patients who require arterial puncture for arterial blood gas analysis are exposed to pain. We evaluated the potential effect of a vapocoolant spray on reducing pain in this population. METHODS: SNOW study was a multicentre, randomised, single-blind, placebo-controlled, assessor-masked, superiority trial conducted in four intensive care units in French hospitals. We randomly assigned critically ill adult patients (aged ≥18 years) to one of two treatment groups (vapocoolant spray or placebo) before an arterial puncture for arterial blood gas analysis. The primary outcome was the intensity of the patient's visual analogue scale rating of pain immediately after the arterial puncture, as assessed by masked assessors. The analysis is reported in the modified intention-to-treat population, which included all randomised patients except those who withdrew or did not consent to continue and those who did not receive their allocated treatment because they met a criterion for ineligibility. The trial was registered on Clinicaltrials.gov with the identifier NCT03973385. RESULTS: From November 12, 2020, to January 12, 2022, 201 patients were randomised to receive either vapocoolant spray (101 patients) or placebo spray (100 patients); 194 received the allocated intervention and 192 were included in the analysis (96 in each allocation group). In the modified intention-to-treat analysis, both the best and worst scenarios for handling with missing data demonstrated that the use of vapocoolant spray was significantly associated with a lower visual analogue scale pain score at the end of the arterial puncture procedure (effect size [Cohen's d]: -0.30 [95% confidence interval: -0.58 to-0.01] and -0.48 [-0.77 to -0.19], respectively). No instances of serious adverse events were reported. CONCLUSIONS: In critically ill adult intensive care patients, the use of vapocoolant spray reduced pain during arterial puncture for blood gases, without significant side effects.