Conclusions Evidence shows the effectiveness and superiority of adrenaline for outcomes of most clinical relevance among outpatients with acute bronchiolitis, and evidence from a single precise trial for combined adrenaline and dexamethasone.
The strength of evidence for this reduction in admission rates was considered low based on the GRADE system, largely because it came from a single trial; however, recent empirical evidence suggests that reliance on evidence from a single precise trial that has been carried out well is reasonable.
For clinicians using trials we suggest that when a meta-analysis is not available, a focus on the most precise trial is reasonable provided it is adequately powered.
For clinicians and guideline authors trying to use systematic reviews and trials, we cautiously suggest that when a meta-analysis is not available, then a focus on the most precise trial is reasonable provided it is adequately powered (that is the confidence intervals exclude values that would change the clinical decision) and adequately conducted.
About the size of a lunchbox, it resembles the prototype invented a century ago, when judges and lawyers first recognized the value of keeping precise trial records, though most machines now store information on hard drives and floppy disks.
For systematic reviewers we suggest that: (1) key trial(s) in a review deserve greater attention (2) systematic reviewers should check agreement of the most precise trial and the meta analysis.
The Precise Trial is using adipose tissue derived cells for transendocardial injections in patients with ischemic cardiomyopathy.
We calculated the p-value for the most precise trial and meta-analysis.
The estimates of effect for the most precise trial and meta-analysis were generally similar.
Finally as suggested in Figure 1, even if the most precise trial is identified, it still needs to be critically appraised, and, if unacceptably flawed, the second most precise trial examined, etc.
Figure 3 shows the comparison of p-values from the most precise trial and the meta-analysis.
