Ventilatory Management of ARDS Before and During ECMO

Acute respiratory distress syndrome (ARDS) is characterized by an acute onset of respiratory failure with arterial hypoxemia and lung stiffening, due to a massive “lesional” (i.e., not from cardiac origin) pulmonary edema. Mechanical ventilation is mandatory to guarantee viable gas exchange but may, at the same time, cause ventilator-induced lung injury (VILI). The use of a lung protective strategy based on tidal volumes of 6 ml/kg of predicted body weight and plateau pressure kept below 30 cmHO has been shown to improve patient’ss survival. Some positive end-expiratory pressure (PEEP) should always be used in patients with ARDS, and some data suggest that higher levels of may ameliorate the survival of the most severe ones. Recruitment maneuvers are a valuable tool in improving oxygenation. Recent data reinforced the role of early prone position in more severely hypoxic patients. To date no pharmacologic strategy has shown a clear benefit in reducing mortality from ARDS, except for the use of neuromuscular blocking agents in the early course of the disease, once again in the subgroup of more severely hypoxic patients. When patients are connected to ECMO, the ventilatory strategy heads toward a more protective strategy, with a further reduction of tidal volumes, respiratory rate, and FiO. The practice of different ECMO centers is more heterogeneous on the use of aggressive “lung recruitment” as opposed to “lung collapse” strategies. Finally, new ventilatory modalities are expected to improve patient-ventilator interaction and enhance the use of assisted breathing during ECMO.