Lower tidal volumes in Brazil, also in patients without acute respiratory distress syndrome?

Abstract

In a recent study, Azevedo and colleagues [1] show tidal volumes (V T ) to be low in patients in Brazilian ICUs. By showing this, it is clear that ventilation practice in Brazil mirrors worldwide changes, at least with regard to V T in patients with acute respiratory distress syndrome (ARDS) [2,3]. Eff orts to implement protective ventilation have been largely restricted to patients with ARDS, which is understandable since its benefi cial eff ects were convincingly demonstrated in these patients only. It is not unreasonable, however, to consider that lower V T also benefi ts patients without ARDS [4], although it could also be argued that lower V T strategies could harm patients without ARDS since it may increase sedation and maybe even paralysis needs, which are associated with increased incidence of delirium, ventilator-induced diaphragm dysfunction, and longer duration of ventilation. Furthermore, the new ARDS defi nition categorizes patients as having mild, moderate and severe ARDS [5]. It has been questioned whether attempts to control V T should be restricted to patients with moderate or severe ARDS. Consequently, the ICU community remains reluctant to use lower V T in patients without ARDS and patients only having mild ARDS, and desires randomized controlled trial (RCT) evidence. When planning a RCT, one would like to know to what V T the ‘lower’ V T is to be compared. We would like to know, therefore, what V T was used in patients without ARDS, in patients with mild ARDS, and in patients with moderate or severe ARDS in Brazilian ICUs?