Patient characteristics were assessed with descriptive statistics and frequency distributions. Categorical characteristics were compared using chi-square test or Fisher’s exact test. Continuous characteristics were compared using independent samples t-test or Mann-Whitney U test.
The primary analysis examined ventilator-free days as a function of ED sedation depth. A multivariable linear regression model was constructed to adjust for potentially confounding variables using backward elimination. A priori baseline characteristics with known prognostic significance for mortality in ED mechanically ventilated patients were purposefully selected for model inclusion (age, indication for mechanical ventilation, tidal volume, illness severity). Other clinically relevant and biologically plausible variables significant in univariate analysis at a p < 0.10 level were also included in the model. Collinearity was assessed and the model used variables that were independent of other variables. All tests were two-tailed, and a p value < 0.05 was considered statistically significant.
From prior work regarding early deep sedation in the ICU and ED, we assumed a difference in mean ventilator-free days of 2.5 between groups. For 80% power and α of 0.05, we estimated a sample size of 324 patients (162 per group) would be required [8 (link), 9 , 11 (link), 14 ].
The primary analysis examined ventilator-free days as a function of ED sedation depth. A multivariable linear regression model was constructed to adjust for potentially confounding variables using backward elimination. A priori baseline characteristics with known prognostic significance for mortality in ED mechanically ventilated patients were purposefully selected for model inclusion (age, indication for mechanical ventilation, tidal volume, illness severity). Other clinically relevant and biologically plausible variables significant in univariate analysis at a p < 0.10 level were also included in the model. Collinearity was assessed and the model used variables that were independent of other variables. All tests were two-tailed, and a p value < 0.05 was considered statistically significant.
From prior work regarding early deep sedation in the ICU and ED, we assumed a difference in mean ventilator-free days of 2.5 between groups. For 80% power and α of 0.05, we estimated a sample size of 324 patients (162 per group) would be required [8 (link), 9 , 11 (link), 14 ].
