Platypnea-Orthodeoxia: Bilateral Lower-Lobe Pulmonary Emboli and Review of Associated Pathophysiology and Management:

Platypnea-orthodeoxia syndrome in a postoperative patient: a case report

Background

We report a case of platypnea–orthodeoxia syndrome observed in a complex clinical situation associating a bilateral pleural effusion, lobar pulmonary embolism, and a partial anomalous pulmonary venous return.

Case presentation

A 57-year-old Caucasian woman developed acute dyspnea in the postoperative course of an elective gynecological surgery for advanced stage ovarian cancer. Preoperative evaluation had failed to reveal any respiratory or cardiac problem. After evidence of a low arterial oxygen saturation, blood gas analysis from the central venous line correctly inserted in the right internal jugular vein revealed a higher oxygen saturation than in the arterial compartment. A thoracic computed tomography showed bilateral pleural effusion, lobar pulmonary embolism, and a drainage of a left pulmonary vein into the left innominate vein. This unique combination resulted in an uncommon cause of platypnea–orthodeoxia syndrome.

Conclusion

Often associated with right-to-left shunting, platypnea–orthodeoxia syndrome may be observed in complex clinical conditions with several factors influencing the ventilation/perfusion ratio. The paradoxical finding of a higher oxygen saturation in a central venous line than in an arterial line should prompt the clinician to look at the possibility of partial anomalous pulmonary venous return. No specific treatment is required in asymptomatic adults, except for an echocardiographic follow-up to detect the onset of pulmonary hypertension.

Platypnoea-orthodeoxia syndrome due to a right-to-left interatrial shunt following pneumonectomy

A 62-year-old man presents with breathlessness 6 months following right pneumonectomy for lung adenocarcinoma. Previous investigations had not yielded a diagnosis and his symptoms were progressing. The patient described worsened symptoms when stood up (platypnoea), with profound hypoxia until laid supine (orthodeoxia). Platypnoea-orthodeoxia syndrome due to a right-to-left interatrial shunt was diagnosed on contrast-enhanced transoesophageal echocardiography with the patient undergoing successful percutaneous patent foramen ovale closure. Patent foramen ovale is often asymptomatic with a population prevalence of around 20%-30%. Anatomical shifts postpneumonectomy can open, or worsen a previously closed interatrial communication leading to right-to-left shunting of blood. Platypnoea-orthodeoxia is under-recognised, impairing quality of life and patient outcome. Investigations can be falsely reassuring, or poorly sensitive for the causative pathology. Percutaneous closure is safe with high success rates and this case highlights the need for a high index of suspicion for shunts, particularly in postpneumonectomy patients.