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.