ID:140 FC-D09-2 Perioperative nitric oxide weaning strategy in a surgical case of pulmonary embolism

Background: Inhaled nitric oxide (iNO) is commonly used for the management of pulmonary hypertension to improve oxygenation and reduce pulmonary vascular resistance. However, discontinuation of iNO may occasionally lead to worsening in oxygenation, necessitating its reintroduction. Clinical Course/Activities: We report the case of a 74-year-old man who was transported to our hospital with dyspnea and loss of consciousness. He was diagnosed with pulmonary thromboembolism, and due to hemodynamic instability, emergency surgery was performed. Under cardiopulmonary bypass with cardiac arrest, thrombi were removed from both pulmonary arteries. However, weaning from cardiopulmonary bypass was difficult, leading to the initiation of venoarterial extracorporeal membrane oxygenation (VA-ECMO) and iNO. ECMO was successfully discontinued on postoperative day (POD) 3, and NO was gradually tapered and iNO was discontinued on POD 5. However, oxygenation worsened, necessitating the reintroduction of iNO. After intratrachial suctioning and postural changes, oxygenation improved, and iNO was discontinued again on POD 6. The patient was weaned from mechanical ventilation on POD 8 and was discharged on POD 28 without major complications. Discussion: Rebound hypoxemia following iNO withdrawal is a known phenomenon, potentially related to increased pulmonary vascular resistance and ventilation-perfusion mismatch. In this case, retained secretions and suboptimal lung recruitment may have contributed to oxygenation deterioration. Appropriate respiratory care and positioning played a crucial role in stabilizing respiratory function and enabling successful iNO discontinuation. Conclusion: We experienced a case of difficult weaning from iNO after pulmonary thromboembolectomy. Careful assessment of respiratory status, including airway clearance and repositioning, is essential to prevent rebound hypoxemia and facilitate successful weaning from iNO.