B52-41 Use of Inhaled Epoprostenol to Facilitate Ventilator Weaning in Scleroderma-Associated Group 1 Pulmonary Arterial Hypertension and Acute Right Heart Failure

Abstract Background Patients with Group 1 pulmonary arterial hypertension (PAH) are highly susceptible to acute right ventricular (RV) failure when exposed to positive pressure ventilation, which increases pulmonary vascular resistance (PVR) and compromises RV preload. In these patients, intravenous pulmonary vasodilators can exacerbate ventilation-perfusion (V/Q) mismatch by dilating vessels in poorly ventilated regions. Inhaled epoprostenol (iEPO) provides selective pulmonary vasodilation only in well-ventilated lung units, improving oxygenation and reducing RV afterload without systemic hypotension. We present a case of scleroderma-associated PAH (Group 1) complicated by acute RV failure and refractory hypoxemia after intubation, successfully managed with iEPO. Case Presentation A 68-year-old woman with scleroderma-associated PAH (mPAP 29 mmHg, PVR 5 Wood units, on macitentan/tadalafil) presented with hypoxemic respiratory failure secondary to necrotizing pneumonia and empyema. CT chest showed multifocal consolidation and loculated effusions, consistent with severely impaired gas exchange. Despite antibiotics and drainage, she developed septic shock and worsening hypoxemia requiring intubation (PaO2/FiO2 ratio 82). Shortly after initiation of positive pressure ventilation, she became profoundly hypotensive with severe RV dilation and septal flattening on echocardiography, consistent with acute RV failure. She required dual vasopressor support (norepinephrine and vasopressin). Given concern that IV pulmonary vasodilators would worsen V/Q mismatch in her diseased lung, inhaled epoprostenol (50 ng/kg/min; patient ∼46kg) was initiated. Within hours, oxygenation improved, vasopressor requirements decreased, and repeat echocardiogram showed reduced RV size and improved septal position. Epoprostenol was weaned by 10ng/hr about 48hrs after initiation. (Figure below with Pre and Post Epo. administration). She was successfully extubated to high-flow nasal cannula within 48 hours and later returned to baseline oxygen requirements. Conclusion In patients with decompensated Group 1 PAH who develop acute RV failure following mechanical ventilation, inhaled epoprostenol offers a targeted, physiologically rational intervention. By selectively lowering pulmonary arterial pressures without worsening V/Q mismatch, iEPO can stabilize hemodynamics, improve oxygenation, and facilitate ventilator weaning in critically ill PAH patients. This abstract is funded by: None