Quantitative data analysis
death
EVENT, RECRUITMENT
Adherence was measured by the proportion of each intervention component performed and captured daily; the number of staff trained; and intervention reach (admissions screened divided by IMV admissions during the trial period). Due to sequential recruitment of clusters over time, we did not measure adherence over time, but provide the final mean adherence proportions for each ICU, ranked from highest to lowest. The trial’s primary outcome was the duration of IMV, measured from initiation of ventilation to the first successful extubation event. The estimate of the treatment effect was a time and cluster adjusted hazard ratio (HR) with 95% confidence intervals. The duration of IMV was analysed using a Cox proportional hazards model, with a frailty term for clustering by ICU. The time to event outcome was censored at the transition from usual care to the intervention training period, hospital discharge, 90-days, death, or if the child received a tracheostomy. We derived an absolute measure of effect by calculating the median of the model-based prediction of survival duration at all 22 periods in the stepped wedge trial and the difference between the intervention and usual care periods, and we summarised the extent of variability over the 22 periods using the interquartile range.