Comparison of lung weights. Lung weights of 78 patients with acute lung injury (ALI) upon admission (red circles) in comparison to the values of 43 mechanically ventilated trauma patients with morphologically and functionally normal lungs (reference ventilated, gray circles). Dashed lines mark the 95% reference intervals for total lung mass and total lung volume, respectively, calculated from reference ventilated patients. Because reference ventilated patients were ventilated with the same positive end-expiratory pressure (10 cmH2O) and also underwent computed tomography during uninterrupted mechanical ventilation, only these reference ventilated patients were used for the graphical comparison with ALI patients in this graph. ALI patients whose data points fall within the gray box did not have an increased lung weight.