Respiratory controversies in the critical care setting. Should tidal volume be 6 mL/kg predicted body weight in virtually all patients with acute respiratory failure?

Over the last 2 decades, it has become clear that mechanical ventilation itself can cause lung injury and affect outcome. The development of ventilator-induced lung injury is strongly associated with overdistension of lung parenchyma, and limiting lung stretch saves lives in patients with acute lung injury. The debate in this paper is whether all patients on mechanical ventilation should be managed with a tidal volume (V(T)) of 6 mL/kg predicted body weight. Current data indicate that reducing lung stretch should be the standard for all patients with acute lung injury and acute respiratory distress syndrome who require ventilatory support. However, insufficient data exist to indicate that a V(T) of 6 mL/kg predicted body weight should be the standard for all patients who require mechanical ventilation. Whether V(T) is the correct target for therapeutic interventions is debatable. Plateau pressure may be a better target for assessing and preventing alveolar over-distension. As the data evolve, it is conceivable that the actual V(T) used should be based on the individual patient's lung mechanics rather than assuming that one V(T) will suit all patients. Consensus at this time is not possible, and this paper presents the arguments on both sides of the controversy.