(1123) Negative Pressure Assist Ventilation to Wean off Venovenous Extracorporeal Membrane Oxygenation

Introduction: Negative pressure ventilation (NPV) has been used as lifesaving ventilation since 1928 with the practice eventually lost to modern positive pressure ventilator (PPV). NPV has seen renewed interest in its use for patients with chronic neuromuscular disorders and respiratory muscle weakness. Though there have been reports of NPV used to prevent orotracheal intubation and wean patients off of PPV. We present a case of NPV used to de-escalate veno-venous extracorporeal membrane oxygenation (VV-ECMO) support in a mechanically ventilated patient.

Description: A 40 year old female with a history of systemic lupus erythematosus, common variable agammaglobulinemia, epilepsy, and gastroparesis with TPN dependence presented with mitral valve endocarditis complicated by bacteremia and embolic strokes. Her course was further complicated by secondary hemophagocytic lymphohistiocytosis and severe acute respiratory distress syndrome (ARDS) requiring VV-ECMO support. Her course was prolonged and complex incurring pneumothoraces, right ventricular dysfunction, pulmonary hypertension, ventilator associated pneumonias, and fibrotic lung changes attributed to ARDS. While supported on PPV and VV-ECMO she tolerated weaning of sedation and participated in daily physical therapy. She recovered her native ability to oxygenate without the support of the ECMO lung. However, despite several months of support, her native lung carbon dioxide clearance did not recover. She was declined consideration for lung transplantation at multiple institutions. Facing limited options, continuous NPV assist via a cuirass was added to PPV regimen. After 114 days of VV-ECMO support, she only required 72-hrs of NPV to safely wean sweep gas flow and was successfully decannulated from ECMO. She survived a total of 28 days off VV-ECMO with PPV-NPV assist ventilation.

Discussion: NPV assist to PPV was implemented to decrease the respiratory effort, increase functional residual capacity, improve ventilatory distribution, recruit lung, and decrease ECMO support. After initiating negative pressure assist via cuirass the patient’s tidal volume improved from (80 -120) to (180 - 290) ml-per-breath. To our knowledge this is the first case describing successful use of NPV used to de-escalate VV-ECMO support in mechanically ventilated patient.