Statistical analysis
Categorical data are presented as numbers, percentages, and rates, while continuous data as mean and standard deviation, or median and range, when appropriate. A chi square test or Fisher’s exact test were performed to analyze categorical data, while unpaired Student T test or Mann Whitney test were applied depending on patients’ distribution. Two-way analysis of variance for repeated measures was applied to verify respiratory differences in the two groups. Multivariate logistic regression analysis (MLRA) was used to assess the effect of PEEP on intubation, adjusted for the covariates listed as baseline features. Variation inflation factor (VIF) was used to evaluate for collinearity. Variables with VIF>2 were considered colinear and excluded from the analysis. A p-value of <0.05 was considered statistically significant. Statistical analysis was performed using the GraphPad Prism 8.0 software package (GraphPad Software, San Diego, CA).