SHM Converge Scientific Abstract ePoster Gallery-Help! Lay Me Back Down, I Can't Breathe! Platypnea-Orthodeoxia Syndrome

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Platypnea-orthodeoxia syndrome (POS) is an underrecognized cause of hypoxia that should be suspected when oxygen levels worsen in the seated or upright position and improve when the patient lies supine, especially after cardiac and pulmonary causes have been excluded. The document emphasizes that right-to-left shunting through a patent foramen ovale (PFO) can produce severe, refractory hypoxia even when right atrial pressures are normal. POS may be more likely when obstructive sleep apnea (OSA) coexists with a PFO, as this can increase the likelihood of shunting.<br /><br />Diagnosis can be supported by echocardiography with bubble study, which shows bubbles crossing to the left side of the heart, and by measuring shunt fraction to estimate how much the PFO is affecting oxygenation. A mobile interatrial septum on echocardiography suggests a larger shunt and may predict more significant symptoms.<br /><br />The document also highlights practical diagnostic steps for calculating shunt fraction, including arterial blood gases on room air and after 100% oxygen administration. Recognition is important because PFO closure can improve oxygenation, reduce morbidity, and improve quality of life.<br /><br />Overall, the key message is to consider POS in patients with positional hypoxia, particularly when standard workup is unrevealing and a PFO-related shunt is possible.

Asset Subtitle

Rita Poon

Meta Tag

Author List Megan Ohlfest, Rita Poon, Sneha Daya

Category Clinical Vignettes

Concept Platypnea-Orthodeoxia Syndrome

Concept Patent Foramen Ovale

Concept Hypoxia

Concept Right-to-Left Shunt

Concept Supine Position

Distinguished Non-Finalist

Presenter Organization MedStar Georgetown University Hospital

Presenting Author Rita Poon

Track Adult

Keywords

platypnea-orthodeoxia syndrome

positional hypoxia

patent foramen ovale

right-to-left shunt

hypoxia

obstructive sleep apnea

bubble study

echocardiography

shunt fraction

pfo closure

Platypnea-Orthodeoxia Syndrome

Patent Foramen Ovale

Hypoxia

Right-to-Left Shunt

Supine Position