Unexplained Hypoxemia

Patent Foramen Ovale Right-to-Left Shunt PFO
  • Ferdinando Luca LoriniEmail author
  • Bruno Rossetto
  • Francesco Ferri


Assessment of unexplained hypoxemia and the inability to wean a patient from ventilatory support are potential uses of echocardiography in the intensive care unit. Causes of hypoxemia that can be diagnosed by echocardiography include intracardiac right-to-left shunting, pulmonary embolus, and disorders of the left ventricle such as left ventricular systolic and/or diastolic dysfunction and mitral valvular abnormalities that can lead to pulmonary edema. If no cardiac abnormality is identified (ventricular or valvular dysfunction), right-to-left shunting must be considered, and the most common cause is patent foramen ovale (PFO).


Patent foramen ovale PFO Right-to-left shunt Atrial septal defects Contrast echocardiography Bubble test 

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Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Ferdinando Luca Lorini
    • 1
    Email author
  • Bruno Rossetto
    • 2
  • Francesco Ferri
    • 1
  1. 1.Department of Anesthesia and Intensive Care MedicineASST Papa Giovanni XXIIIBergamoItaly
  2. 2.Department of Anesthesia and Intensive Care MedicineASST Gaetano PiniMilanItaly

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