Mechanical Ventilation during Extracorporeal Membrane Oxygenation in Acute Respiratory Distress Syndrome: A Narrative Review

Abstract

Acute respiratory distress syndrome (ARDS) is a life-threatening condition involving acute hypoxemic respiratory failure. Mechanical ventilation remains the cornerstone of management for ARDS; however, potentially injurious mechanical forces introduce the risk of ventilator-induced lung injury, multiple organ failure, and death. Extracorporeal membrane oxygenation (ECMO) is a salvage therapy aimed at ensuring adequate gas exchange for patients suffering from severe ARDS with profound hypoxemia where conventional mechanical ventilation has failed. ECMO allows for lower tidal volumes and airway pressures, which can reduce the risk of further lung injury, and allow the lungs to rest. However, the collateral effect of ECMO should be considered. Recent studies have reported correlations between mechanical ventilator settings during ECMO and mortality. In many cases, mechanical ventilation settings should be tailored to the individual; however, researchers have yet to establish optimal ventilator settings or determine the degree to which ventilation load can be decreased. This paper presents an overview of previous studies and clinical trials pertaining to the management of mechanical ventilation during ECMO for patients with severe ARDS, with a focus on clinical findings, suggestions, protocols, guidelines, and expert opinions. We also identified a number of issues that have yet to be adequately addressed.

Keywords: acute respiratory distress syndrome; extracorporeal membrane oxygenation; mechanical ventilation; multiple organ failure; ventilator-induced lung injury.

Figure 1

(a) Mechanical ventilation can cause VILI including volutrauma, atelectrauma, barotrauma, and biotrauma, which has been shown to contribute to multiple organ failure and mortality in patients with ARDS; (b) ECMO mitigates ventilation load to allow the lungs to rest, and may reduce the risk of VILI and multiple organ failure. (VILI, ventilator-induced lung injury; ARDS, acute respiratory distress syndrome; ECMO, extracorporeal membrane oxygenation; MP, mechanical power; V_T, tidal volume; Pplat, plateau pressure; ∆P, driving pressure; RR, respiratory rate; FiO₂, fraction of inspired oxygen).

Figure 1

(a) Mechanical ventilation can cause VILI including volutrauma, atelectrauma, barotrauma, and biotrauma, which has been shown to contribute to multiple organ failure and mortality in patients with ARDS; (b) ECMO mitigates ventilation load to allow the lungs to rest, and may reduce the risk of VILI and multiple organ failure. (VILI, ventilator-induced lung injury; ARDS, acute respiratory distress syndrome; ECMO, extracorporeal membrane oxygenation; MP, mechanical power; V_T, tidal volume; Pplat, plateau pressure; ∆P, driving pressure; RR, respiratory rate; FiO₂, fraction of inspired oxygen).