Introduction
Platypnea-orthodeoxia syndrome (POS) is defined by dyspnea and hypoxemia in the upright position, which improves upon recumbency. While often linked with hepatopulmonary syndrome, intracardiac etiologies, particularly a patent foramen ovale (PFO), may also be responsible. PFOs are typically managed with device closure, and while rare, device migration can occur unbeknownst to the patient with resultant critical sequelae.
Methods
Here, we present the case of an 89-year-old female with a medical history of hypertension, diabetes, and coronary artery disease status post PCI, who arrived with severe dyspnea and was subsequently intubated for profound hypoxia. A chest CT angiogram ruled out pulmonary embolism but identified a foreign object in the pulmonary artery. A bubble contrast echocardiogram confirmed a septal defect and PFO. Further patient history revealed prior placement of a PFO closure device in her native country 30 years ago. Following extubation, she was found to remain significantly hypoxic when sitting and required high-flow nasal cannula support whenever upright, consistent with POS. Her work-up remains ongoing.
Results
POS results from right-to-left shunting of blood, bypassing pulmonary oxygenation. This can occur through intracardiac or intrapulmonary shunts. In this case, migration of the septal closure device likely re-established an interatrial communication, permitting right-to-left shunting and POS physiology due to elevated right atrial pressures.
Conclusions
Our case highlights the importance of considering prior device-related interventions in patients with unexplained hypoxemia and evaluating oxygenation changes in different body positions for added diagnostic value.