Acute Hypoxic and Refractory Respiratory Failure Induced by an Underlying PFO: An Unusual Case of Platypnea Orthodeoxia and Transient Complication after Transcatheter Closure

Dynamic right-to-left interatrial shunt may complicate severe COVID-19

Right-to-left (RTL) interatrial shunt (IAS) may complicate select cases of COVID-19 pneumonia. We describe the use of serial imaging to monitor shunt in critically ill patients. A 52-year-old man presented with COVID-19 pneumonia. Hypoxia worsened despite maximal medical therapy and non-invasive ventilation. On day 8, saline microbubble contrast-enhanced transthoracic echocardiography revealed a patent foramen ovale (PFO) with RTLIAS. Invasive ventilation was initiated the next day. The course was complicated by intermittent severe desaturation without worsening aeration or haemodynamic instability, so PFO closure was considered. However, on day 12, saline microbubble contrast-enhanced transoesophageal echocardiography excluded RTLIAS. The patient was extubated on day 27 and discharged home 12 days later. Thus, RTLIAS may be dynamic and changes can be detected and monitored by serial imaging. Bedside echocardiography with saline microbubble contrast, a simple, minimally invasive bedside test, may be useful in the management of patients with severe hypoxia.