“Awake” extracorporeal membrane oxygenation (ECMO): pathophysiology, technical considerations, and clinical pioneering

Abstract

Venovenous extracorporeal membrane oxygenation (vv-ECMO) has been classically employed as a rescue therapy for patients with respiratory failure not treatable with conventional mechanical ventilation alone. In recent years, however, the timing of ECMO initiation has been readdressed and ECMO is often started earlier in the time course of respiratory failure. Furthermore, some centers are starting to use ECMO as a first line of treatment, i.e., as an alternative to invasive mechanical ventilation in awake, non-intubated, spontaneously breathing patients with respiratory failure (“awake” ECMO). There is a strong rationale for this type of respiratory support as it avoids several side effects related to sedation, intubation, and mechanical ventilation. However, the complexity of the patient–ECMO interactions, the difficulties related to respiratory monitoring, and the management of an awake patient on extracorporeal support together pose a major challenge for the intensive care unit staff. Here, we review the use of vv-ECMO in awake, spontaneously breathing patients with respiratory failure, highlighting the pros and cons of this approach, analyzing the pathophysiology of patient–ECMO interactions, detailing some of the technical aspects, and summarizing the initial clinical experience gained over the past years.

Use of extracorporeal membrane oxygenation in cystic fibrosis in an Australian cystic fibrosis centre

“…As a bridge to transplantation, some patients with CF may require non‐invasive and/or mechanical ventilation. A select few are now requiring ECMO . A recent analysis of the Extracorporeal Life Support Organization (ELSO) registry between 1998 and 2013, demonstrated an overall survival rate of 52% in the CF population, with 38 of 72 patients surviving their ECMO run.…”

“…It is also unclear how patients who did not receive lung transplants were withdrawn from ECMO support. More recently, the use of ‘awake’ ECMO in CF, defined as the use of ECMO in extubated patients, demonstrated excellent survival outcomes in a case series . This allowed participation in pre‐transplantation rehabilitation and oral nutritional intake …”

Mechanical Ventilation during Extracorporeal Membrane Oxygenation in Patients with Acute Severe Respiratory Failure

“…To avoid potential adverse effects of deep sedation and paralysis, some pioneering centers start to use ECMO as the first line therapy, rather than rescue therapy after MV failure. Thus, there is accumulating evidence on the use of ECMO in awake, spontaneously breathing patients [83–85]. In patients waiting for lung transplantation, those underwent ECMO with spontaneous breathing demonstrated improved survival when compared to other bridging strategies [84].…”

Ventilation during extracorporeal support

“…In fact, the potential benefits of spontaneous ventilation need to be evaluated together with its potential detrimental effects [14]. Indeed, high inspiratory efforts and very high respiratory drive, often independent from the blood gas and pH value have been described in the acute phase of ARDS [13,20].…”