Rare.

Diagnostic criteria: reduction of more than 4 % of the saturation of oxygen (SpO2) when the patient moves from the supine to the sitting or standing position. The cause is posssibly an effect of the positioning on the configuration of the interauricular septum reorientating the blood flow coming from the inferior vena cava through a patent foramen ovale.

Clinical signs: refractory hypoxemia and/or dyspnea in the standing or sitting position;  sometimes uncomfort caused by the orthostatism. Diagnosis: echocardiography with injection of microbubbles in a vein draining into the inferior vena cava.

Possible causes:

-        increased lung resistance: postpneumonectomy status, pulmonary embolism, kyphoscoliosis

-        modified compliance of the right ventricle: Ebstein disease, constrictive pericarditis, pericardial effusion, myxoma of the right atrium.

Treatment: percutaneous closure of the foramen ovale keeping in mind that in some cases, it can act as a safety valve in case of  right ventricular hypertension and so avoid right heart failure.

Another cause of platypnea-orthodeoxia, due to a different mechanism, is the hepatopulmonary syndrome (see this term)

Anesthetic Implications:

according to the cause; avoid increasing the pulmonary vascular resistances.

References :

-        Girard E, Sicot E, Leroux L, Morteau B et al.
Le syndrome platypnée-orthodéoxie, une cause inhabituelle de détresse respiratoire après coelioscopie.
Ann Fr Anesth Réanim 2005 ; 24 : 1282-6

-        Guérin P, Lambert V, Godart F, Legendre A et al.
Transcatheter closure of patent foramen ovale in patients with platypnea-orthodeoxia : results of a multicentric French registry. 
Cardiovascul Interv Radiol 2005 ; 28 : 164-8.

-        Canivet A, Lancellotti P.
Syndrome de platypnée-orthodéoxie : une observation clinique perspicace.
Rev Méd Liège 2017 ; 72 : 494-8.

-        Köhl S, Inghilleri P, Cartigny G, Eicher JC, Benkhadra S.
Une désaturation isolée en postopératoire : diagnostic de syndrome platypnée-orthodéoxie.
Anesth Réanim 2019 ; 5 : 200-3.

Updated: June 2019