D104-21 Acute Patent Foramen Ovale Shunt Reversal in a Post-Cardiac Arrest Patient With Refractory Hypoxia

Abstract Introduction Patent foramen ovales (PFOs) are found in about 25% of the adult population. Most findings are incidental and are of little clinical significance. However, in some instances, sudden elevated right atrial pressures can create a right-to-left shunt, a life-threatening complication allowing for de-oxygenated blood to bypass the lungs. PFOs can be culprits of strokes and refractory hypoxia. In the intensive care unit (ICU) ventilator use often causes quick changes in hemodynamics which may allow PFOs to cause adverse outcomes requiring prompt identification and change in management strategy. Description A 70-year-old female was admitted for management of nausea and vomiting secondary to partial gastric outlet obstruction and grade D esophagitis. Patient underwent successful naso-gastric tube decompression and was advanced to a clear liquid diet. She then experienced an aspiration episode that resulted in pulseless electrical activity (PEA) arrest, but successful return of spontaneous circulation (ROSC) occurred after three rounds of cardiopulmonary resuscitation (CPR). The patient was transferred to the ICU. After some time the patient developed refractory hypoxia with an arterial blood gas (ABG) showing a paO2 of 49 mmHg despite increases to positive end-expiratory pressure (PEEP), maxed 1.0 FiO2 and intact ventilator circuit checks. Chart review eventually revealed a prior 2D echocardiogram being significant for a PFO. Point-of-care ultrasound (POCUS) with agitated saline demonstrated the appearance of bubbles within three cardiac cycles, therefore consistent with the presence of acute right-to-left intra-cardiac shunt formation. Thus, PEEP was decreased; phenylephrine was added, and inhaled epoprostenol was initiated in hopes to equalize left and right sided pressures by decreasing pulmonary resistance and increasing systemic afterload. Right-to-left shunting seemingly decreased as the patient’s oxygenation improved with a repeat ABG showing a paO2 of 76 mmHg. Interventional cardiology ultimately performed a successful PFO closure after a risk-benefit analysis. Discussion PFOs have limited indications to close due to their relative lack of clinical significance; however, this case exhibits one of those rarer circumstances while simultaneously highlighting the importance of POCUS in the ICU. It is prudent to be knowledgeable of ventilator-related physiological changes, causes of refractory hypoxia and nuanced differences between commonly utilized medications as this can help aid in early identification allowing for management adjustments to be made thus preventing potential adverse outcomes in critically ill patients. This abstract is funded by: None