Analysis of patients with severe ARDS on VV ECMO with pulmonary hypertension or right ventricular failure treated with iNO: a retrospective observational study

Abstract Background: In a retrospective observational study, we investigated patients with severe acute respiratory distress syndrome (ARDS) undergoing veno-venous (VV) extracorporeal membrane oxygenation (ECMO) support with known pulmonary arterial hypertension (PAH) and/or right ventricular (RV) failure treated with iNO. Objective: We analysed clinical characteristics such as time on mechanical ventilation, weaning from VV ECMO, organ dysfunction, the iNO therapy in terms of indication, dosing and duration, the ability of iNO to lower PAH in responder and non-responder patients, the survival rate, in-hospital mortality and long-term survival. Results: Of the 657 patients identified with ECMO support, 292 under VV ECMO support were evaluated and n=55 patients with iNO were included. We found that in-hospital mortality and long-term survival were poor in patients with severe ARDS under VV ECMO support with persistent PAH and/or RV failure. A rescue therapy with the pulmonary vasodilator iNO showed that only one-third of the cohort responded to the therapy with a sufficient decrease of the mean PAP. Survival between iNO responder and non-responder showed a trend albeit data between the groups were not statistically significant. We did not find a higher rate of continuous renal replacement therapy as marker for acute renal failure when iNO concentrations were ≤ 20 ppm and when the treatment duration stayed ≤ 3 days. Conclusions: This retrospective observational study suggests that persistent PAH and/or RV failure is associated with worse clinical outcome in patients with severe ARDS and VV-ECMO support. Concomitant treatment with the pulmonary vasodilator iNO reduced PAH and/or reversed RV dysfunction in only one-third of the patient population (iNO responder patients) but did not alter the rate of acute kidney failure.