Discussion
Tension pneumomediastinum is a rare but potentially lethal condition
seen in critically ill patients. Traditionally, pneumomediastinum occurs
in young patients with asthma. During an asthmatic attack, rapid
breathing causes alveolar rupture into the lower-pressure mediastinum.
This condition is often harmless and resolves spontaneously as air is
absorbed with time.(3) On the other hand, tension
pneumomediastinum can also occur due to prolonged mechanical
ventilation, particularly in settings of high end-expiratory
pressure.(2) Understandably so, this complication has
seen an increase in incidence following the emergence of the COVID-19
pandemic, as high end-expiratory pressure ventilation has been utilized
to a greater extent for management of COVID-19-related respiratory
distress.(1) This form of pneumomediastinum is far
more complicated and requires urgent intervention.
Tension pneumomediastinum is thought to occur in patients with COVID-19
secondary to diffuse alveolar damage. The increased presence of diseased
alveoli on the mediastinal surface allows for preferential rupture into
the mediastinum due to the pressure gradient between the alveoli and the
perivascular sheaths. Further spreading of the pulmonary interstitial
emphysema into the mediastinum is subsequently known as the Macklin
effect.(4) In patients with COVID-19, the diseased
lung may create a one-way valve at the mediastinal/pleural border, which
can subsequently lead to air retention in the mediastinum. Increased
pressure in the mediastinum can cause compress mediastinal contents. In
particular, compression of the great vessels can lead to decreased
venous return, hypotension with tachycardia, and potentially
cardiovascular collapse.(2)
Currently, management for tension pneumomediastinum in the COVID-19
population has largely been conservative.(1) Different
approaches include reducing airway pressures and adjusting ventilator
settings to allow for permissive hypercapnia in an effort to reduce
pressure gradients across the mediastinal surface. These methods may be
sufficient for management of tension pneumomediastinum in stable
COVID-19 patients, but those who are unstable may require immediate
surgical decompression. After review of the current literature, we
describe the first case report of operative management for a massive
tension pneumomediastinum secondary to COVID-19.(1) Of
note, there was one previous report of tension pneumomediastinum
secondary to COVID-19 that resolved with bedside mediastinotomy via the
Chamberlain procedure.(5)
In our patient with COVID-19, a tension pneumomediastinum formed in the
chest and neck, with subsequent spread to the arms bilaterally. The
enlarging pneumomediastinum caused difficulty breathing and progressive
dysphonia with an increased pitch in the tone of his voice. Due to
impending airway obstruction, the patient was sent for emergent
mediastinal drainage. Specifically, we created a subxiphoid pericardial
window, employed subxiphoid and suprasternal drainage of the
pneumomediastinum, and performed substernal dissection with lighted
scope. The anterior mediastinum was decompressed completely using our
operative procedure, resulting in rapidly reduced swelling in the
patient’s neck, improvement of his voice, and disappearance of the
crepitus with complete clinical and radiographic healing.
Here, we describe the first operative management of massive tension
pneumomediastinum secondary to SARS-CoV-2 infection. In this case of a
48-year-old male with severe COVID-19 pneumonitis requiring intubation,
we used an operative technique that provided rapid decompression of
unstable tension pneumomediastinum using a pericardial window and
mediastinal drain. This case demonstrates that precipitous decline may
occur in a patient with diseased lung parenchyma such as COVID-19 and
that our method may offer an effective operative solution for rapid
decompression required for massive tension pneumomediastinum
dissolution.