Platypnoea–orthodeoxia syndrome (POS) is a rare disorder characterised by both dyspnoea (platypnoea) and arterial desaturation (orthodeoxia) in the upright position, with improvement in the supine position. We report an unusual case in which an 82-year-old woman developed severe hypoxaemia with POS after left total knee replacement. A significant difference in alveolar–arterial blood gas oxygen tension was demonstrated, and hypoxaemia failed to respond to 100% oxygen supply. A patent foramen ovale with a right-to-left shunt was evident on transoesophageal echocardiogram employing colour Doppler and agitated normal saline studies. Interestingly, the patient’s symptoms resolved within 6 months with ongoing chest physiotherapy, without surgical or medical intervention.
- cardiovascular medicine
- radiology (diagnostics)
- respiratory system
- gas/free gas
- geriatric medicine
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Contributors TA suggested the diagnosis and encouraged the investigations. He did the majority of the writing of the article. BJ contributed in writing the case and was involved directly in the care and management of the patient and followed up with the patient. FE gave general guidance and supported in writing the case discussion. GAA provided oversight. All authors gave their final approval before submission.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
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