Effect of Mechanical Ventilation Strategy on Lung Injury in Patients With Less Severe Acute Respiratory Distress Syndrome: Targeted on RAGE

During the past two decades, there current concept has evolved significantly that ventilator-induced lung injury (VILI) may not only impose a direct mechanical stress and subsequent injury to the lungs, but may also induce local as well as systemic inflammation responses, generally referred as biotrauma.1 Patients with ARDS often die of severe systemic inflammatory response syndrome (SIRS) and multiorgan dysfunction2 rather than refractory hypoxemia. Ranieri et al found that patients with less severe ARDS, i.e., a lung injury score of 2.5 or less, receiving ventilation with lung protective strategy involving low tidal volume (7.5 mL/kg PBW) and high PEEP could attenuate the pulmonary and systemic cytokine response compared with conventional ventilation with high tidal volume.3 Stuber et al found an increase in pro-inflammatory cytokines in the lung and plasma of patients with ARDS within 1 hour after switching the patients from a protective to non-protective ventilator strategy.4 The receptor for advanced glycation end-products (RAGE) was recently identified as a marker of injury to the alveolar type I epithelial cells5. Clinical studies showed that the plasma level of RAGE was associated with severity of lung injury and clinical outcome, and low tidal volume strategy ventilation accelerated the decline in plasma RAGE levels. These results suggest plasma RAGE level might be a reliable biomarker of alveolar epithelial injury in acute lung injury and may associated with ventilator induced lung injury6. Although, current approach to mechanical ventilation of a patient with ARDS emphasizes the use of lower tidal volumes with lower plateau pressures to avoid causing lung overdistension and ventilator associated lung injury (VILI)7; however, in the real world, some studies showed that strictly reduction of tidal volume to 6ml/kg PBW was modest in modern time, and was noticed only in patients with greater lung injury scores8. The benefit of VT strictly reduction to 6ml/kgP