Use of Hybrid Veno-venous-pulmonary Artery ECMO in A Patient with Respiratory Failure Secondary to COVID-19

ABSTRACT

Background: Extracorporeal membrane oxygenation (ECMO) is a form of cardio-pulmonary life support used for patients with respiratory and/or cardiac failure. Hybrid ECMO is a sophisticated circuit to match the exact hemodynamic demands in patients who are refractory to traditional ECMO settings. Case A 43-year-old male presented with dyspnea for four days. On physical examination, he exhibited increased work of breathing and decreased breath sounds bilaterally. Pulse oximetry was 70% on room air, minimally improved to 75% on maximum high flow nasal cannula. He was found to be COVID-19 positive and demonstrated diffuse bilateral lung consolidation on CT chest consistent with severe acute respiratory distress syndrome. Patient was intubated but continued to show poor oxygenation with P/F ratio of 71 (Normal >400). Veno-Venous (VV) ECMO was started with cannulations into the right femoral vein (RFV) and right internal jugular vein (RIJV);this resulted in an initial improvement of partial pressure of oxygen (pO2) in arterial blood gas. However, within a few days, pO2 started to decrease with visual evidence of recirculation of oxygenated blood into the venous drainage line. A transthoracic echocardiography revealed severe pulmonary artery (PA) hypertension secondary to respiratory failure with PA pressure of 116mmHg (Normal 18-25mmHg). This prompted a revision of the ECMO circuit to offload the right ventricle. Revised circuit included a cannula in the RFV for venous drainage and oxygenated venous return through two pathways cannula in the RIJV (approximately 1 liter return), and a third cannula inserted through the left subclavian vein terminating into the main PA (approximately 4 liters return). Hereon, patient was able to maintain adequate pO2 for the remainder of his hospital stay until he was transferred to a lung transplant center. Conclusion: Our case illustrates the clinical sophistication of hybrid VV-PA ECMO-especially in patients with PA hypertension and impending right-sided heart failure. As respiratory failure secondary to COVID-19 becomes more prevalent, hybrid ECMO may provide a practical solution to protect the right heart in the journey to lung transplant.