expiratory rib cage compression, endotracheal suctioning, and vital signs

sir, we read with interest bousarri et al.’s article which has been recently published in your journal under the title “the effect of expiratory rib cage compression before endotracheal suctioning on the vital signs in patients under mechanical ventilation.”[1] while the article is potentially of interest to readers, there are several aspects that need attention. first of all, it concerns us that all patients with peep were excluded from this study. the usual practice internationally is that all patients who require positive pressure ventilation  have a small amount of peep; therefore, this raises significant issues in regard to external validity of the study as many centers would have no patients with similar treatment characteristics as those who were included in .....