Lung-protective ventilator strategies are considered standard practice in the care
of patients with the acute respiratory distress syndrome (ARDS). To minimize ventilator-induced
lung injury, attention is directed at avoidance of alveolar overdistention and cyclical
opening and closing. The lowest possible plateau pressure and tidal volume (VT) should be selected. A reasonable target VT in all mechanically ventilated patients is 6 mL/kg. A topic of much controversy is
the optimal setting of positive end-expiratory pressure (PEEP). Results of a meta-analysis
using individual patient data from three randomized controlled trials suggest that
higher PEEP should be used for moderate and severe ARDS, whereas lower PEEP may be
more appropriate in patients with mild ARDS. PEEP should be set to maximize alveolar
recruitment while avoiding overdistention. Volume and pressure limitation during mechanical
ventilation can be described in terms of stress and strain. Fraction of inspired oxygen
(Fio
2) and PEEP are typically titrated to maintain arterial oxygen saturation (Spo
2) of 88 to 95% (Pao
2 55–80 mm Hg). There is currently no clear proven benefit for advanced modes.
Keywords
acute respiratory distress syndrome - lung-protective ventilation strategies - mechanical
ventilation - positive end-expiratory pressure - ventilator-induced lung injury