Under Pressure: Spontaneous Pneumomediastinum with Resultant Cardiac Tamponade Influencing the Decision to Initiate Extra-Corporeal Membrane Oxygenation

Abstract

IntroductionWe present a case of a rare but serious adverse consequence of Acute Respiratory Distress Syndrome (ARDS) secondary to COVID-19 infection: spontaneous pneumomediastinum and pneumopericardium resulting in cardiac tamponade. Case descriptionA 35 year old unvaccinated female with a history of degenerative disc disease, Sjogren's disease, and mild persistent asthma presented with COVID-19 pneumonia. On admission, she required near-maximum heated high flow oxygen, yet desaturated with minimal movement. Three days later, she noted sharp chest pain with worsening oxygenation. Chest radiograph revealed diffuse subcutaneous air with concern for bilateral pneumothoraces, and follow up CT revealed pneumomediastinum, pneumopericardium, and extensive subcutaneous emphysema. She was subsequently intubated. She ultimately developed signs of obstructive shock, and an emergent chest CT demonstrated tamponade physiology on the heart from the mediastinal air. Bedside echocardiogram was unable to be performed due to air surrounding the heart. At this time, her Murray score was 3.8, and discussions began regarding transfer to a referral center for Extracorporeal Membrane Oxygenation (ECMO). Given her tenuous hemodynamics and the prospect of transfer in a low-pressure aircraft, a mediastinotomy tube was placed with a large air leak, tidaling of the tube, and improvement in hemodynamics. On arrival at the ECMO center (Saint Joseph Hospital), her tamponade physiology had improved, but she was requiring progressively higher ventilator pressures due to her severe ARDS. Her extensive pneumomediastinum, pneumoperitoneum, and subcutaneous emphysema would likely only be worsened by higher positive end-expiratory pressures. Due to this complex physiology, she was deemed a VVECMO candidate and was cannulated the day after transfer. Following cannulation, her pneumomediastinum and pneumoperitoneum improved, and eventually her mediastinotomy tube no longer demonstrated an air leak or tidaling. As such, it was removed and her hemodynamics remained stable with no evidence of recurrent tamponade. DiscussionThis presented a unique case in which the choice for VVECMO was influenced not only by severity of ARDS, but also by the complicating factor of positive pressure ventilation causing worsening tamponade physiology due to spontaneous tension pneumomediastinum. Additionally, this case adds to the reports of spontaneous pneumomediastinum in COVID-19 infection, as our patient had no history of trauma or barotrauma before this occurred. On literature review, we have only found one other case report in which a tension pneumomediastinum in COVID-19 required bedside mediastinotomy. Physicians should be aware of this potentially fatal complication and expedite referral to an ECMO center.