Vapocoolant spray reduces pain scores by Cohen's d -0.30 to -0.48 in critically ill adults during arterial puncture

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Australian critical care : official journal of the Confederation of Australian Critical Care Nurses Published June 5, 2026 Medically reviewed June 5, 2026 Study authors: Jacq Gwenaëlle, Minghetti Fabien, Souppart Virginie, Labreuche Julien, Aegerter Philippe, Chauvin Va… PubMed ↗ NCT03973385 ↗ DOI ↗ By Dr. Ji-eun Park, MD · Brain, Mind & Pain

Key Takeaway

Consider vapocoolant spray to reduce immediate pain during arterial puncture in critically ill adults.

This randomized controlled trial evaluated pain management during arterial puncture in critically ill adult patients aged 18 years or older. The study population included 201 patients randomized to receive either vapocoolant spray or placebo spray. A total of 194 patients received the allocated intervention, and 192 were included in the final analysis.

The primary outcome measured the intensity of the patient's visual analogue scale rating of pain immediately after the arterial puncture. Results indicated lower pain scores with vapocoolant spray compared to placebo. The effect size was Cohen's d: -0.30 in the best scenario and -0.48 in the worst scenario. The 95% CI for the effect size ranged from -0.58 to -0.01 in the best scenario and -0.77 to -0.19 in the worst scenario.

Safety data indicated no instances of serious adverse events. Patients who withdrew or did not consent to continue were excluded from analysis. Tolerability was described as without significant side effects. Follow-up duration was not reported. The study was conducted in four intensive care units in French hospitals.

The findings suggest a reduction in immediate procedural pain for this specific population. Clinicians should consider the magnitude of the effect when weighing the use of vapocoolant spray in their practice. Further research may be needed to confirm long-term safety and efficacy in broader settings.

Study Details

Study typeRct

Sample sizen = 201

EvidenceLevel 2

Follow-up216.0 mo

PublishedJun 2026

PMID41996883

TrialNCT03973385

View Original Abstract ↓

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.