[neverdem]

You mean they can’t find either lung perforation or something generating gas in the thorax? It would seem impossible.

Look up visceral and parietal pleura. The visceral pleura lines the outside of the lungs, IIRC. It develops a defect. Pop, you lose the nagative pressure in your chest cavity that keeps your lungs expanded.

[HiTech RedNeck]

So, doesn’t the rupture need to be patched somehow to restore full function?