Ability of respiratory pulse pressure variation to predict fluid responsiveness in ARDS: still an unanswered question?

Excerpt

We read with interest the study of Lakhal and colleagues [1] suggesting that respiratory pulse pressure variation (PPV) is not an accurate predictor of fluid responsiveness in patients with acute respiratory distress syndrome (ARDS) ventilated with low tidal volume (Vt). They stated that the poor performance of PPV is attributed to small changes in respiratory pleural pressure related to low Vt, such that PPV is low even in the case of marked cardiac preload dependency. These findings are not surprising since in this study [1] the mean static compliance was not very low (40 cmH₂O); therefore, the percentage of transmission of alveolar pressure to the pleural space was not really altered. Thus, the ventilation with low Vt induced small variations in pleural and transpulmonary pressures. …