Pleural effusion during weaning from mechanical ventilation: a prospective observational multicenter study

Abstract

Background: Pleural effusion is common during invasive mechanical ventilation, but its role during weaning is unclear. We aimed at assessing the prevalence and risk factors for pleural effusion at initiation of weaning. We also assessed its impact on weaning outcomes and its evolution in patients with difficult weaning.

Methods: We performed a prospective multicenter study in five intensive care units in France. Two hundred and forty-nine patients were explored using ultrasonography. Presence of moderate-to-large pleural effusion (defined as a maximal interpleural distance ≥ 15 mm) was assessed at weaning start and during difficult weaning.

Results: Seventy-three (29%) patients failed weaning, including 46 (18%) who failed the first spontaneous breathing trial (SBT) and 39 (16%) who failed extubation. Moderate-to-large pleural effusion was detected in 81 (33%) patients at weaning start. Moderate-to-large pleural effusion was associated with more failures of the first SBT [27 (33%) vs. 19 (11%), p < 0.001], more weaning failures [37 (47%) vs. 36 (22%), p < 0.001], less ventilator-free days at day 28 [21 (5-24) vs. 23 (16-26), p = 0.01], and a higher mortality at day 28 [14 (17%) vs. 14 (8%), p = 0.04]. The association of pleural effusion with weaning failure persisted in multivariable analysis and sensitivity analyses. Short-term (48 h) fluid balance change was not associated with the evolution of interpleural distance in patients with difficult weaning.

Conclusions: In this multicenter observational study, pleural effusion was frequent during the weaning process and was associated with worse weaning outcomes.

Keywords: Mechanical ventilation; Pleural effusion; Ultrasonography; Weaning.

Fig. 1

Study flow chart; green and red squares denote International Consensus Conference classification of weaning success and failure, respectively; *three patients were not extubated despite the success of the first SBT because of borderline cough, and experienced a novel fatal complication leading to death before any extubation attempt; they could not be classified according to the International Consensus Conference **including 192 planned and 7 unplanned. *** Including 39 planned and 2 unplanned

Fig. 2

Kaplan–Meier curves for the probability of successful extubation after the first spontaneous breathing trial in mechanically ventilated patients with (red lines) or without (blue lines) moderate-to-large pleural effusion