Proning on Veno-venous ExtraCorporeal Membrane Oxygenation in Treatment of Severe ARDS in COVID-19: A Retrospective Case Series

ABSTRACT

Aim and background: Infection due to SARS-CoV-2 may lead to an atypical ARDS, requiring in the most severe cases VV ECMO. The management of persistent severe hypoxemia under VV ECMO requires a multistep clinical approach including prone positioning which could improve oxygenation. Objective: To assess the synergistic effect of prone ventilation and VV-ECMO in addition to lung-protective ventilation to improve patient outcomes in severe ARDS. Materials and methods: Fortis hospital has been an established ECMO center prior to the COVID-19 pandemic but has now become a primary referral center for ECMO retrieval of critically ill patients. In the past 10 months, we had 19 ECMO patients. All patients who underwent ECMO insertion had CT imaging done on the day of ECMO insertion. Patients with inhomogeneous lung opacities on imaging were postulated to potentially benefit from proning on ECMO. We would like to present a case series of 3 patients (2 retrievals and 1 in-house) subjected to prone ventilation immediately after initiation of VV ECMO in view of ARDS with refractory hypoxia, high driving pressures, and Murray score of >3. Femoro-jugular configuration of VV ECMO was used with adequate anticoagulation. All patients were subjected to proning and supining with a dedicated team of 8-10 members including a senior intensivist and airway expert at the head end and perfusionist taking care of the ECMO circuit along with 6 support staff on side of the patient and 1-2 staff for placing/removing the head support, chest, and pelvic bolsters. All patients received immunomodulation with methylprednisolone for the persistent maladaptive hyperinflammatory states. Ventilatory parameters on conventional lung-protective ventilation were compared to parameters on ECMO at the initiation of proning and after completion of prone sessions. Any complications associated with proning were noted. Results: We describe 3 patients with severe COVID-19 bronchopneumonia with refractory hypoxemia who received prone ventilation on VV ECMO. The median age of patients was 40 years with 1 male and 2 female patients. The median time from symptom onset to mechanical ventilation was 7 days and from mechanical ventilation to VV ECMO initiation was 1.5 days. The median duration on VV-ECMO was 5 days with a duration of prone sessions lasting 18 hours. The mean driving pressure has reduced by 17.6% with an improvement in compliance by 26.3%. The paO2 and P/F ratio improved by 63.2% and 260%, respectively, on ECMO support and these changes were sustained post-ECMO decannulation. None of the patients had any major complications associated with proning. The median duration of hospital stay was 30 days. Days to discharge were prolonged due to sepsis from secondary infection. All 3 patients survived to hospital discharge with minimal to no oxygen requirement, mobilized to an adequate functional capacity to perform activities of daily living. Conclusion: ECMO is often used in patients with severe ARDS and refractory hypoxemia to improve oxygenation and survival. Prone positioning concurrently with ECMO in selected patients can further aid in optimizing alveolar recruitment and reducing ventilator-induced lung injury, which ultimately may be associated with a reduction in-hospital mortality.