Abstract
We report a case of a patient with pulmonary hypertension who presented with acute hypoxemic respiratory failure. The patient had continued refractory hypoxemia despite a prolonged ICU admission that included ventilatory support, and empiric therapy for pulmonary embolism and pneumonia. Transthoracic echocardiography (TTE) revealed a patent foramen ovale (PFO), which after percutaneous closure resulted in profound improvement in hypoxemia and clinical status.
1
Case report
A 45-year-old morbidly obese male presented to the emergency department with progressive shortness of breath and fatigue. His symptoms worsened over four days, limiting his ability to ambulate. His medical history was notable for obstructive sleep apnea, secondary polycythemia, congestive heart failure, and continuous home oxygen therapy. His daily medications included aspirin 325 mg daily, carvedilol 3.125 mg BID, enalapril 20 mg daily, felodipine 10 mg daily, hydrochlorothiazide 25 mg daily, potassium 10 mEq BID, colchicine 0.6 mg BID, esomeprazole 40 mg daily, and indomethacin 50 mg TID PRN.
Upon presentation, he was afebrile, with a pulse of 98 bpm and blood pressure 127/88 mmHg. He was tachypneic with a rate of 30 breaths per minute and hypoxic with an oxygen saturation of 73% on room air. He was morbidly obese (body mass index of 64.9) and was in moderate respiratory distress. Cardiac examination revealed a regular rate and rhythm and a 2/6 holosystolic murmur at the left lower sternal border. Breath sounds were diminished at the bases bilaterally. There was 2 + lower extremity edema extended to the knees bilaterally. An initial ABG on room air was obtained and revealed the following: pH 7.30, PAO2 70 mmHg, PCO2 44 mmHg, and oxygen saturation 71%. His respiratory status deteriorated on bilevel positive airway pressure (BiPAP) support, so he was intubated and admitted to the ICU.
An electrocardiogram revealed a normal sinus rhythm, a rate of 93 bpm, RAD, and a right bundle branch block ( Fig. 1 ). CXR revealed an enlarged cardiac silhouette, pulmonary edema, and small bilateral pulmonary effusions ( Fig. 2 ). Lower extremity venous duplex scan revealed left soleal and posterior tibial deep venous thromboses.
Initial management included mechanical ventilatory support, anticoagulation with heparin for presumed pulmonary embolism (PE), and empiric antibiotic therapy for possible pneumonia. A TTE with bubble study demonstrated a right-to-left interatrial shunt, consistent with a PFO. The RV was severely dilated with reduced function and had estimated systolic pressure of 45 mmHg. Given the venous thrombi and RV dilation, intravenous fibrinolytic therapy was administered for presumptive PE. Five days following fibrinolytic therapy, the patient’s clinical status continued to deteriorate with a severe, persistent alveolar-arterial oxygen gradient and poor systemic oxygenation.
For further evaluation, a right heart catheterization was performed and revealed the following pressures (mm Hg): RA 18, RV 80/10, PA 80/40 (mean 58), and PCWP 30. Cardiac output was 7.2 L/min and cardiac index was 2.9 L/min 2 by Fick. An oxygen shunt run revealed a femoral artery saturation of 88%, IVC 57.8%, SVC 63.1%, RA 61.7%, RV 65%, PA 66.7%, pulmonary vein 99%, and LA 86%. Q p /Q s was 0.81. Normal pulmonary vein saturations indicated adequate lung ventilation and perfusion, and the LA saturation of 86% indicated right to left shunting through the PFO causing systemic hypoxia.
The PFO was transiently occluded with a 24 mm balloon ( Fig. 3 ) for 10 minutes without change in RV or PA pressures and an increase in the femoral arterial O 2 saturation to 94%. The PFO was then successfully closed with a 25 mm occlusion device ( Fig. 4 ) with use of intracardiac echocardiography (ICE), which allows operators to evaluate cardiac structures such as cor triatriatum or a chiari network that may interfere with device deployment; furthermore, ICE permits accurate ascertainment of device positioning and allows optimal sizing for device placement. Immediately following PFO closure, the femoral arterial saturation improved to 97%. Serial ABGs revealed PaO2 (mmHg) increased from 70.9 one day prior to PFO closure to 85.7 one day following the procedure.
