Fact-Checking Buffalo Chest
“It was after this realization that I began trying to find the ‘point’ of California, to locate some message in its history.”
A few months ago, I found myself in one of my favourite places – the American Museum of Natural History in New York City. Meandering through the levels of skeletons, taxidermy and peculiar dioramas plucked from distant North American epochs, I reflected. For the decades that New York City has, and has not, been my home these static scenes anchor me and also arouse something faintly appreciable as Rousseau’s criticisms of modernity. Do these faux landscapes delight me because, in them, I see freedom? Do they transport me to the dread of residency and remind me that I persisted and matured? Does their permanence act as mental flotsam to which I cling in the churning, whirling, walloping commotion of nasal swabs, airports, rental cars and unfamiliar pillows? Do they ground my life – our lives – before this rotten pandemic?
I always approached the American bison diorama with pause. Looking at it summons a dilute, naïvely-romantic impression of American manifest destiny, inculcated by forced-memorization of poems like Whitman’s “Pioneers! O Pioneers!” Yet, this most recent visit was different – a surgical mask fogged my vision and I had arrived with new friends. But rather than disclose mist-like ruminations obscuring my existential horizon like the water vapour on my eyeglasses, I turned to small-talk.
“The reason that bison were pushed to near extinction is because they have a communicating pleural cavity,” I said. “Puncturing one lung, simultaneously drops both lungs because of their anatomy.”
I recalled a consult, when I was a fellow, for bilateral pneumothoraces following placement of a subclavian central line in the surgical ICU. My mentor told me that the patient had ‘buffalo chest’ physiology and this was the indelible genesis of my trivial chit-chat. My focus turned outwards again and even my reflection in the diorama glass looked bored with itself.
And so, it was to my surprise and immense interest that Blacha and colleagues published a very recent ‘fact check’ on the buffalo chest. Their journey was triggered by a great review of pleural disease published a few years back by Drs. Feller-Kopman and Light.
What they did
Literature reviews were performed seeking human case reports of ‘buffalo chest’ and for review of the mediastinal anatomy of the North American bison. A questionnaire was sent to 50 Dutch veterinarians; a select group of veterinarians with specialty in exotic animals were consulted including the veterinarian from whom the term ‘buffalo chest’ was originally coined. Finally, autopsies of North American bison were performed to investigate for fenestrations between pleural spaces using visual inspection and instillation of water and methylene blue and examination of the contralateral pleural space.
What they found
They identified 47 case reports of patients with buffalo chest. 31 of the cases followed cardiothoracic surgery which is understood to cause interpleural communications. However, the remaining 16 were in patients with no history of cardiothoracic surgery – 10 developed bilateral pneumothoraces following unilateral iatrogenic causes [e.g., central line placement, transbronchial biopsy, chest tube thoracostomy] while 6 presented with spontaneous bilateral pneumothoraces.
Data on North American bison was lacking. Their questionnaire and consultations found no clear evidence for interpleural fenestrations in bison. They were unable to obtain contralateral water and methylene blue on a single bison at the Rotterdam Zoo that was euthanized for medical reasons other than respiratory problems. After meeting with Dr. Thorlson in Arizona [see below], they were able to visually inspect the mediastinum of 8 bison at a meat processing plant in Colorado. 50% of the bison did have visible interpleural fenestrations.
If consciousness is a nothingness between the ‘past which no longer is and the future which is not yet’ then we are compelled to fill this vacuum with cohesive stories. These narratives anchor ourselves [e.g., the American bison diorama], but also professions [e.g., buffalo chest] and nations [e.g., manifest destiny]. As the details of these stories can drift it is important, I think, to continually revisit them to test their veracity.
What is the origin of ‘buffalo chest’? Is this a myth? Does it happen in humans? The curiosity of Blacha and colleagues quite literally led them on a westward American journey. To my eye, this is the most interesting and, frankly, endearing aspect of their report. That is, they located and interviewed the veterinarian with whom Schorlemmer and colleagues communicated in their original case report. Dr. Kenneth Throlson was located in ‘a small town in the south of Arizona’ and was reportedly surprised to learn that his observation had been incorporated into the lexicon of thoracic medicine.
Dr. Thorlson had worked with thousands of American bison and observed that about 50% of them had gross interpleural fenestrations on autopsy. He had also noted that some bison died after sustaining a unilateral thoracic puncture injury – typically via a rival’s horn; interpleural connections explain their demise. His observed frequency of pleural fenestrations was confirmed by Blacha and colleagues in a small sample [n = 8] of bison. Importantly, the authors also report that these communications are also present in other mammals such as dogs, horses, cats and rabbits and rightly suggest that their presence in humans are likely underappreciated.
Therefore, in any unilateral pneumothorax, they note, it is wise to inspect the contralateral chest for evidence of cross-communication.
Best wishes, warmest regards,