The American Bison is one of my favorite mammals, so it is no surprise that I found this interesting and a good teaching point last year while working along with the V.A. thoracic surgery service: http://www.nejm.org/doi/full/10.1056/NEJMicm010281#t=article — This article presents a case which illustrates a concept known as a “buffalo chest”, or absence of anatomical separation of the two hemithoraxes, secondary to genetics, trauma, or iatrogenesis. I saw these in patients who had undergone median sternotomies for various cardiothoracic procedures. It’s also a physiology seen in trauma patients, patients with cancer who have had resections, people with various kinds of primary pulmonary disease, or just randomly by genetic bad luck (I imagine, though the article doesn’t list this as a specific cause). This is known as a buffalo chest because the American Bison (or at least according to the article, some) has a single, contiguous pleural space. While I would never use the word “easy” to describe the hunting of buffalo, particularly with bows from horseback, this facilitated the killing of them for food (or sick entertainment in the case of some poor buffalo shot by settlers off a train), as a GSW or penetrating arrow would to their broad sides could lead to a tension physiology.

Consider this possibility in the crashing patient with tension pneumothorax that doesn’t resolve with a unilateral chest tube, especially if any of the risk factors described. I agree with something described (and criticized by some)  in the FOAMed trauma world — nobody should die of traumatic arrest without decompression of the bilateral chests. I think this supports the empiric decompression of the contralateral chest in the positive pressure-ventilated patient in undifferentiated cardiac arrest where pneumothorax is wanting to be ruled out, and would really like to see more research on better ways to manage it in the acute setting.