A pulmonary shunt is the passage of deoxygenated blood from the right side of the heart to the left without participation in gas exchange in the pulmonary capillaries.

Hypoxemia is common in pulmonary hypertension (PH) and may be partly related to ventilation/perfusion mismatch, low diffusion capacity, low cardiac output, and/or right-to-left (RL) shunting. To determine whether true RL shunting causing hypoxemia ...

Intrapulmonary shunt will be always mildly overestimated because of a minimal constant contribution of a physiologic shunt (right to left shunt of the Thebesian and bronchial circulation) [34].

Echocardiography, including transthoracic and transesophageal approaches, is especially useful for detecting intrapulmonary right-to-left shunts, such as those resulting from pulmonary arteriovenous malformations.

2014年1月6日 · Inadequate contrast (e.g., from large body habitus), poor effort during Valsalva maneuver, and predominant left-to-right shunt flow can decrease the sensitivity of detecting a right-to-left shunt on transthoracic contrast echocardiography, which ranges from …

2023年7月17日 · The lungs are further divided into five separate lobes, two on the left and three on the right. Each lobe is made up of small sacks of air called alveoli. There are approximately 300 million alveoli in healthy lungs. It is at the surface of alveoli where diffusion from air into pulmonary arterioles occurs. [1] [2] [3]

In pulmonary disease, areas of the lung may not receive ventilation (e.g., as airways are blocked or collapsed). Perfusion to these areas is therefore wasted as no gas exchange takes place; …

2010年4月4日 · Right-to-left shunting during exercise in PAH is due to an abnormally high pulmonary vascular resistance leading to right atrial pressure exceeding left atrial pressure, forcing systemic venous blood through a patent foramen ovale (PFO) directly into the systemic arterial circulation.

PAVM is a benign condition yet presenting several times as refectory hypoxia due to intrapulmonary right-to-left shunt. Depending on the size and number of PAVM presented and the degree of shunt the clinical presentation can vary from asymptomatic (despite altered gas exchange as noted in blood gas analysis) to severe hypoxia with no correction ...

First described in 1949, platypnea-orthodeoxia syndrome is a clinically underrecognized syndrome defined by O 2 desaturation in the upright position but not in the supine position. Reported causes include intracardiac shunting, pulmonary vascular shunting, ventilation-perfusion mismatch, or a combination of these mechanisms.