- subject at a high risk of death, according to investigator's opinion, in the 3 months following enrollment from other causes than acute respiratory distress syndrome (e.g., severe neurological damage or cancer patients in terminal stages of the disease). - subject currently being treated with an endothelin receptor antagonist. - subject currently being treated with another pulmonary vasodilator. - anticipated need for non-invasive mechanical ventilation, endotracheal intubation or tracheostomy at the time of screening. - history of mechanical ventilation (invasive or non-invasive) in the last 7 days. - documented history of end-stage liver disease, cirrhosis or idiopathic pulmonary fibrosis (ipf) with or without pulmonary arterial hypertension. - aspartate aminotransferase (ast) or alanine aminotransferase (alt) > 3-times the upper limit of normal (uln). - anticipated discharge from the hospital or transfer to another hospital which is not a study site within 96 hours. - participation in another interventional clinical trial in the 15 days prior to enrollment. - known hypersensitivity to ambrisentan or propylene glycol.

- subject at a high risk of death, according to investigator's opinion, in the 3 months following enrollment from other causes than acute respiratory distress syndrome (e.g., severe neurological damage or cancer patients in terminal stages of the disease). - subject currently being treated with an endothelin receptor antagonist. - subject currently being treated with another pulmonary vasodilator. - anticipated need for non-invasive mechanical ventilation, endotracheal intubation or tracheostomy at the time of screening. - history of mechanical ventilation (invasive or non-invasive) in the last 7 days. - documented history of end-stage liver disease, cirrhosis or idiopathic pulmonary fibrosis (ipf) with or without pulmonary arterial hypertension. - aspartate aminotransferase (ast) or alanine aminotransferase (alt) > 3-times the upper limit of normal (uln). - anticipated discharge from the hospital or transfer to another hospital which is not a study site within 96 hours. - participation in another interventional clinical trial in the 15 days prior to enrollment. - known hypersensitivity to ambrisentan or propylene glycol.

- subject at a high risk of death, according to investigator's opinion, in the 3 months following enrollment from other causes than acute respiratory distress syndrome (e.g., severe neurological damage or cancer patients in terminal stages of the disease). - subject currently being treated with an endothelin receptor antagonist. - subject currently being treated with another pulmonary vasodilator. - anticipated need for non-invasive mechanical ventilation, endotracheal intubation or tracheostomy at the time of screening. - history of mechanical ventilation (invasive or non-invasive) in the last 7 days. - documented history of end-stage liver disease or cirrhosis. - aspartate aminotransferase (ast) or alanine aminotransferase (alt) > 3-times the upper limit of normal (uln). - anticipated discharge from the hospital or transfer to another hospital which is not a study site within 96 hours. - participation in another interventional clinical trial in the 15 days prior to enrollment. - known hypersensitivity to ambrisentan or propylene glycol.

- subject at a high risk of death, according to investigator's opinion, in the 3 months following enrollment from other causes than acute respiratory distress syndrome (e.g., severe neurological damage or cancer patients in terminal stages of the disease). - subject currently being treated with an endothelin receptor antagonist. - subject currently being treated with another pulmonary vasodilator. - anticipated need for non-invasive mechanical ventilation, endotracheal intubation or tracheostomy at the time of screening. - history of mechanical ventilation (invasive or non-invasive) in the last 7 days. - documented history of end-stage liver disease or cirrhosis. - aspartate aminotransferase (ast) or alanine aminotransferase (alt) > 3-times the upper limit of normal (uln). - anticipated discharge from the hospital or transfer to another hospital which is not a study site within 96 hours. - participation in another interventional clinical trial in the 15 days prior to enrollment. - known hypersensitivity to ambrisentan or propylene glycol.