ARDS can be caused by direct lung injury and systemic inflammatory response, the common causes are as follows: 1, the lung itself causes: pneumonia, including bacterial, viral or fungal pneumonia, can cause changes in the lung itself; elderly people inhale stomach contents into the lungs by mistake; toxic substances; patients in car accidents with lung impact injuries, i.e. pulmonary contusions; 2, causes outside the lung: serious infections in other areas, such as cholecystitis and cholangitis form systemic infections or even shock, can lead to ARDS; severe pancreatitis, massive blood transfusion, non-lung trauma such as multiple fractures can also lead to ARDS.