Table of Contents
What does Orthodeoxia mean?
Orthodeoxia means low oxygen saturation in the upright posture and improvement when lying down. Platypnea is dyspnea in an upright position, which improves with recumbency [1]. It is an uncommon and often overlooked cause of dyspnea.
What causes Orthodeoxia?
In the majority of cases, the syndrome is caused by the coexistence of an anatomical heart defect, especially patent foramen ovale (PFO), but also atrial septal defect (ASD) or atrial septal aneurysm (ASA) with septal fenestration, combined with structural or functional abnormalities of other thoracic or abdominal …
Why does platypnea happen?
Platypnea is commonly associated with orthodeoxia and both result from diseases that cause intracardiac or extracardiac right-to-left shunting significant enough to cause hypoxia. Measuring oxygen saturation in different positions should be performed any time platypnea is reported.
What is the mechanism of platypnea?
Two conditions must coexist to cause platypnea-orthodeoxia: an anatomical component in the form of an interatrial communication and a functional component that produces a deformity in the atrial septum and results in a redirection of shunt flow with the assumption of an upright posture.
What causes platypnea?
Causes. Platypnea is usually due to either hepatopulmonary syndrome or an anatomical cardiovascular defect increasing positional right-to-left shunting (bloodflow from the right to the left part of the circulatory system) such as a patent foramen ovale.
Does oxygen improve shunt?
True shunt is refractory to oxygen therapy. This results in what is termed “refractory hypoxemia”. Because refractory hypoxemia does not respond to oxygen therapy, other means should be sought to improve arterial oxygenation.
Is Platypnea curable?
Evaluation for platypnea-orthodeoxia is reasonable in patients with unexplained dyspnea since the condition is potentially curable with closure of the anatomic defect.
Why does Platypnea happen?
Does shunt increase co2?
True, the shunted blood has a high CO2 content. Bypassing the gas exchange surfaces of the lungs, that CO2 content ends up in the arterial circulation, and the arterial CO2 should be expected to rise proportionally to the shunt fraction.
What is the difference between right-to-left shunt and left to right shunt?
A left-to-right shunt allows the oxygenated, pulmonary venous blood to return directly to the lungs rather than being pumped to the body. A right-to-left shunt allows the deoxygenated, systemic venous return to bypass the lungs and return to the body without becoming oxygenated.
Is pneumonia a shunt?
Causes of shunt include pneumonia, pulmonary edema, acute respiratory distress syndrome (ARDS), alveolar collapse, and pulmonary arteriovenous communication.
What is platypnea-orthodeoxia syndrome (POS)?
Platypnea-orthodeoxia syndrome (POS) is an uncommon condition of positional dyspnea (platypnea) and hypoxemia (orthodeoxia). The symptoms occur when the patient is upright and resolve quickly with recumbency. These findings are the opposite of those typically seen in cases of advanced heart failure and can pose a diagnostic dilemma.
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Can intracardiac shunt closure be used to treat platypnea-orthodeoxia syndrome?
When platypnea-orthodeoxia syndrome is due to intracardiac shunting without pulmonary hypertension, intracardiac shunt closure can be curative. In this article, we report a case of platypnea-orthodeoxia syndrome in an 83-year-old woman who was successfully treated by means of percutaneous transcatheter closure of an atrial septal defect.
How is platypnea-orthodeoxia syndrome (pot) diagnosed?
Platypnea-orthodeoxia syndrome should be suspected when an individual has normal oxygen saturations on room air while supine, yet experiences dyspnea and desaturations when upright. Correlation with blood-gas analysis that documents positional change in oxygen tension (Pao2) is certainly helpful.