We propose an additional phase I pilot study to evaluate the effectiveness and safety of Tenecteplase for the treatment of ARDS. Unlike the other fibrinolytics studied in this disease state, Tenecteplase, is more fibrin specific and has increased resistance to plasminogen activator inhibitor (PAI-I) at greater levels than other available fibrinolytics. We have chosen an experimental dose escalation trial design of tenecteplase that has demonstrated initial safety trends in a Phase I acute ischemic stroke trial. The initial dose is 0.1 mg/kg IV and will increase to 0.2 mg/kg, 0.3 mg/kg, with a final cohort of patients receiving 0.4 mg/kg. Drug administration will be a single dose bolus in each cohort. Advancement of dose will occur if safety is not in question in the previous cohort. We hope this will provide an acceptable benefit risk ratio as the mortality of ARDS is approximately 30 - 60%. All patients will be closely monitored for any change in clotting parameters and signs of bleeding. Tenecteplase will be administered via a peripheral IV as described in the package insert.