Hypoxemia in COVID-19 patients: An hypothesis

Area of Science:

• Critical Care Medicine
• Cardiology
• Pulmonology

Background:

• COVID-19 patients present with severe hypoxemia unresponsive to conventional mechanical ventilation.
• These patients often lack increased lung stiffness or severe dyspnea, posing a diagnostic challenge.

Purpose of the Study:

• To hypothesize that a probe-patent foramen ovale (PFO) opening explains unexplained hypoxemia in severe COVID-19.
• To explore the physiological mechanisms linking COVID-19, pulmonary hypertension, and PFO-related shunting.

Main Methods:

• Review of existing literature on PFO prevalence, COVID-19 pathophysiology, and hypercoagulability.
• Discussion of physiological evidence for intracardiac shunting in COVID-19 patients.
• Identification of diagnostic methods like echocardiography and potential therapeutic interventions.

Main Results:

• Hypothesis proposed: increased pulmonary artery pressure in COVID-19 may open a PFO, causing a right-to-left shunt.
• This shunt can lead to severe hypoxemia without significant changes in lung mechanics or dyspnea.
• COVID-19's hypercoagulability and pulmonary emboli contribute to elevated pulmonary pressures.

Conclusions:

• An open PFO is a plausible explanation for severe hypoxemia in select COVID-19 patients.
• Bedside diagnostic tests can identify an open PFO.
• Potential treatments include shunt closure and reduction of pulmonary vascular resistance.