Is Maximal Lung Recruitment Worth It?

Abstract

In their recent article, Borges and colleagues nicely show by computed tomography (CT) that nearly complete lung recruitment may be achieved in most mechanically ventilated patients with acute lung injury/acute respiratory distress syndrome (ALI/ ARDS) (1). Unfortunately, the authors failed to prove that their maximal lung recruitment strategy is safe. To obtain full recruitment, which was defined as PaO2 PaCO2 400 mm Hg, they use an aggressive strategy consisting of a sequential increase in inspiratory pressures up to 60 cm H2O if necessary. However, the extreme values of PaCO2 and pH observed during recruitment can hardly be considered as safe. Furthermore, the minimal gain in reversing collapse beyond 45 cm H2O (Figure 2 of their article) indicates that unnecessarily high distending pressures were probably used. The low rates of barotrauma and hyperinflation on CT do not exclude overdistension, which is easily identified in their data by the increase in PaCO2 and the decrease in cardiac output. More important, overdistension may worsen lung injury, release inflammatory mediators, and induce distant organ failure and death (2, 3). In fact, despite the low number of patients, the 57% mortality rate is unexpectedly high compared with most recent trials and with previous data of the same group. Decades of research have moved us toward a more gentle and rational ventilation (4). Overdistension may be a high price to pay for maximal recruitment.