Is There a Preinterventional Mechanical Ventilation Time Limit for Candidates of Adult Respiratory Extracorporeal Membrane Oxygenation.

Venovenous extracorporeal membrane oxygenation (VV-ECMO) is a useful life support in severe acute respiratory distress syndrome (ARDS). Although prolonged mechanical ventilation (MV) before institution of ECMO is known to be a poor prognostic factor for outcomes of VV-ECMO, a reasonable deadline for this period has not been defined yet. To discover the answer, we reviewed a 9 year institutional experience of adult respiratory ECMO in VV configuration and investigate the relationship between the MV time before ECMO and in-hospital mortality. This retrospective study included 129 adult patients receiving VV-ECMO for ARDS in a single institution from 2007 to 2016. Important demographic and clinical data before ECMO intervention were collected for analyses of in-hospital mortality. The MV time before ECMO independently predicted hospital death in adult respiratory ECMO here. While compared to the patients receiving MV for 7 days or less, the patients receiving MV for more than 7 days before ECMO showed a higher in-hospital mortality rate (77% vs. 38%, p < 0.001). They also experienced a more significant deterioration in respiratory function during MV before the institution of ECMO. Therefore, from the clinical observation, we thought that a 7 day period might be an acceptable limit on MV time before institution of VV-ECMO. Integrating other respiratory parameters into the current PaO2/FiO2 (PF) ratio-based inclusion criteria of adult respiratory ECMO might be helpful to reduce the risk of prolonged MV in selected patients.

Venovenous Extracorporeal Membrane Oxygenation for Acute Respiratory Distress Syndrome in Adults: Prognostic Factors for Outcomes.

Despite a therapeutic option for severe acute respiratory distress syndrome (ARDS), the survival benefit of venovenous extracorporeal membrane oxygenation (VV-ECMO) is still controversial in adults. This study was aimed at investigating the prognostic factors for ECMO-treated ARDS in adult patients.From 2012 to 2015, 49 patients (median age: 57 years) received VV-ECMO in our institution and were included in this retrospective study. The indication of VV-ECMO was a severe hypoxemia (PaO2/FiO2 ratio <70 mmHg) under mechanical ventilation (MV) with a peak inspiratory pressure (PIP) >35 cmH2O and a FiO2 >0.8. To decrease the impact of pulmonary injuries associated with the high-pressure ventilation, the settings of MV on VV-ECMO were downgraded according to our protocol. Outcomes of this study were death on VV-ECMO and death in hospital. Important demographic and clinical data during the treatment were collected for outcome analyses.All patients experienced significant improvements in arterial oxygenation on VV-ECMO. Twenty-four hours after initiation of VV-ECMO, the median PaO2/FiO2 ratio increased from 58 to 172 mmHg (P < 0.001) and the median SaO2 increased from 86% to 97% (P < 0.001). In the meantime, the MV settings were also effectively downgraded. The median PIP decreased from 35 to 29 cmH2O (P < 0.001) and the median tidal volume decreased from 7 to 5 ml/kg/min (P < 0.001). Twelve patients died during the treatment of VV-ECMO and 21 patients died before hospital discharge. Among all of the pre-ECMO variables, the pre-ECMO pulmonary dynamic compliance (PCdyn) <20 mL/cmH2O was identified to be the prognostic factor of death on VV-ECMO (odds ratio [OR]: 6, 95% confidence interval [CI]: 1-35, P = 0.03), and the pre-ECMO duration of MV >90 hours was the prognostic factor of death before hospital discharge (OR: 7, 95% CI: 1-29, P = 0.01).VV-ECMO was a useful salvage therapy for severe ARDS in adults. However, the value of PCdyn and the duration of MV before intervention with VV-ECMO may significantly affect the patients' outcomes.