Data synthesis and analysis
Review Manager (RevMan) version 5.3 (Copenhagen: The Nordic Cochrane
Centre, The Cochrane Collaboration, 2014) was used to calculate the
pooled estimates. Odds ratios (OR) for dichotomous outcomes, the
standardized mean difference (SMD) for continuous data and corresponding
95% confidence intervals (CI) were used for the analyses. The
I2 statistic was used to evaluate the effect of
heterogeneity on the pooled results (I2 >
50% indicated substantial heterogeneity). A fixed-effects model was
used to pool data when the heterogeneity was not significant and a
random effects model was used when significant heterogeneity was
identified. We performed sensitivity analyses of all outcome parameters
by adjusting the effects of the models to assess the robustness of the
results. We perfomed subgroup analyses by type of study and initial or
post-extubation respiratory support. A p -value < 0.05
was considered statistically significant.