Analysis
For analyses evaluating data which were independent between groups, Kruskall-Wallis or Pearson's chi-square tests were performed with Bonferroni correction for multiple comparisons. For data that was not independent (i.e., measurements on multiple days from the same patient), we chose one observation per patient at random or used linear mixed models to first control for patient level effects. Similarly, repeated measures correlation was used with log or cubed transformation as necessary to satisfy assumptions of normality. Dose response relationships between ∆Pes and suggested cut-offs of Pocc, P0.1, and PMI are reported with box-plots [Several thresholds have been proposed using esophageal pressure to characterize high or low inspiratory effort [In addition, the following data were collected on all test days: respiratory mechanics (resistance, peak flow, tidal volume, static respiratory system compliance (CAnalyses were performed with EZR (Saitama Medical Center, Jichi Medical University, Saitama, Japan) and R (R Core Team, Vienna, Austria). Additional details on the materials and methods are provided in the Additional file 