Tension posterior pneumomediastinum in acute respiratory distress syndrome due to COVID-19

摘要

A 52-year-old male was admitted to intensive care unit with respiratory failure secondary to COVID-19 severe acute respiratory distress syndrome (ARDS). After presenting with 2-weeks of dyspnoea, diarrhoea, and fever, he was diagnosed with COVID-19 pneumonia and treated with remdesivir and dexamethasone. He ultimately required mechanical ventilation, and a lung-protective strategy was implemented consisting of a tidal volume of 6 cc/kg, plateau pressure 30 cm H2O, and a low PEEP ARDSNet table. Two days later, pneumomediastinum and widespread subcutaneous emphysema occurred. Eight days into mechanical ventilation, the patient had a cardiac arrest. After resuscitation, refractory hypotension ensued requiring escalating doses of vasopressors. The arterial line tracing demonstrated pulsus paradoxus and transient hand pressure in the subxiphoid area caused episodes of hypotension, which immediately resolved upon release. This may have related to air mobilization into the mediastinum impairing venous return. Transthoracic echocardiogram demonstrated left atrial collapse due to extrinsic compression (Panels A and B; Videos 1 and 2). Volume resuscitation was also instituted with haemodynamic improvement. A non-contrast chest computed tomography (CT) confirmed the presence of pneumomediastinum with a pocket of air extrinsically causing left atrial compression. The patient was repositioned in reversed Trendelenburg while a drainage approach was decided. However, repeat chest CT obtained 6 h later in preparation for CT-guided drainage revealed resolution of the air pocket with left atrial re-expansion (Panels C and D; Video 3 and Supplementary material online, Video S1), and displacement of the air to the upper chest. Unfortunately, the patient had severe multiorgan dysfunction and ultimately expired.