Ventilator induced lung injury (VILI) in acute respiratory distress syndrome (Ards). “barotrauma” to “biotrauma”: case report
Acute respiratory distress syndrome is the most severe manifestation of acute lung injury and it is associated with high mortality rate. ARDS is characterized by the acute onset of diffuse neutrophilic alveolar infiltrates protein-rich edema due to enhanced alveolar-capillary permeability and hypoxemic respiratory failure. Mechanical ventilation is the main ARDS supportive treatment. However, mechanical ventilation is a non-physiologic process and complications are associated with its application. Mechanical ventilation may induce lung injury; referred to as ventilator-induced lung injury (VILI) and it is in form of alveolar rupture due to over distension of alveoli due to positive pressure ventilation i.e.Volutrauma, Barotrauma, Biotrauma. The Biotrauma is a form of VILI is the ability of inflation volume to disrupt the alveolarcapillary interface and promote proinflammatory cytokine released from the lungs and trigger the systemic inflammatory response syndrome, and can lead to inflammatory injury in the lung as well in other organs. The biotrauma is the leading cause of mortality in patient with ARDS. The lung protective ventilation strategy- Low tidal volume ventilation has shown some reduction in mortality in patients with ARDS but mortality is still high in patient with severe ARDS secondary to Pneumocystis jiroveci pneumonia (PJP) despite of lung protective ventilation strategy. In patients with Severe ARDS due to PJP, the outcome can be improved with the use of Extracorporeal life support (ECLS) techniques, such as extracorporeal membrane oxygenation (ECMO) or extracorporealCO2 removal (ECCO2R), because with such technique the patient can be given very low tidal volume 2-4ml/kg/PBW and risk of VILI can be avoided.