The tidal volume fix?

Prior to publication of the ARDSNet trial of tidal volumes (VT) (1), traditional mechanical ventilation often employed VT of 10–15 mL/kg of unadjusted body weight. While these volumes had long been noted to exceed those of healthy subjects [who usually breathe at 6–8 mL/kg of predicted body weight (PBW)], they were considered necessary for intubated and mechanically ventilated patients to prevent progressive atelectasis, avoid dyspnea and maintain appropriate ventilation. A frequent consequence of using larger VT was the application of abnormally high airway pressures and alveolar forces, especially in patients with acute lung injury, a condition in which the functioning lung is small and both lung collapse and edema are prevalent. Elevated airway pressures potentially incur damaging stretch in those lung units that remain aerated. Animal studies that employ large VT associated with high airway pressures reveal regional disruption of the blood-gas interface, together with inflammation, atelectasis, and hypoxemia, especially in pre-injured lungs. Lung damage secondary to large VT [ventilator-induced lung injury (VILI)] has also been linked experimentally to injury of remote organs (1-3)