Summary of findings for the main comparison. Vapocoolant compared with placebo/no treatment for pain treatment during intravenous cannulation.
| Vapocoolant compared with placebo/no treatment for pain treatment during intravenous cannulation | ||||||
| Patient or population: pain treatment during intravenous cannulation Settings: metropolitan hospitals in UK; emergency departments in children’s hospitals in the USA; US school of dentistry; tertiary children's hospital in Canada; Army Medical Centres in the USA; metropolitan teaching hospital in Australia; emergency department of a tertiary hospital in New Zealand Intervention: vapocoolant Comparison: placebo/no treatment | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | Number of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| Placebo/No treatment | Vapocoolant | |||||
| Pain during cannulation | Mean pain during cannulation in the control group was 33 | Mean pain during cannulation in the intervention group was 12.5 lower (18.7 lower to 6.4 lower) | ‐ | 848 (8 RCTs) | ⊕⊕⊕⊝ Moderatea,b,c | |
| Pain at application | Mean pain at application in the control group was 0 | Mean pain at application in the intervention group was 6.3 higher (2.2 higher to 10.3 higher) | ‐ | 461 (4 RCTs) | ⊕⊕⊕⊕ Moderatec | |
| First attempt success | Study population | RR 1.00 (0.94 to 1.06) | 812 (6 RCTs) | ⊕⊕⊕⊝ Moderateb | ||
| 832 per 1000 | 832 per 1000 (782 to 882) | |||||
| Moderate | ||||||
| 853 per 1000 | 853 per 1000 (802 to 904) | |||||
| Adverse events | Study population | Not estimable | 551 (5 RCTs) | ⊕⊕⊝⊝ Lowd | ||
| Mean risk of adverse events in the control group was 0 | All minor and included 4 reports of cold sensation, 3 transient reactions of erythema at the site of spray and 1 report of burning sensation. RD = 0.03, 95% CI 0.0 to 0.05) | |||||
| *The basis for the assumed risk (e.g. median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI) CI: confidence interval | ||||||
| GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate Very low quality: We are very uncertain about the estimate | ||||||
aFour of eight trials described no blinding of participants, but results were consistent with those of blinded studies, and so we did not downgrade for risk of bias
bHigh degree of heterogeneity was not explained by methodological and clinical differences but could be due to the small number of studies, with five studies showing good effects and 3 showing lesser or no effects of vapocoolants. Therefore, we downgraded, giving serious risk of inconsistency
cMeasurements were taken on a VAS 100 scale; although the CI does include the minimally clinically important difference, it also spans the range below the minimally important clinical difference. We downgraded on the basis of small numbers in each trial, which might overestimate treatment effects.
dTrials were not pooled, as adverse effects were reported differently across studies; so again we downgraded to serious for imprecision and for inconsistency for this outcome.