This is a radiograph of the patient's lower right leg, showing a fracture of the tibia.

This an example of another cause of non-cardiogenic pulmonary edema--fat emboli. Whenever there is significant trauma to bone, bits of marrow fat can get into the blood stream, and will generally be caught by the lung capillary bed. The fat is broken down into toxic compounds that damage the lung vasculature and cause leakage of fluid into the lung, interfering with oxygenation and causing an increased A-a (alveolar-arterial) gradient.