At low concentrations, nitric oxide(NO) functions as a cellular messenger and regulator of microcirculation. NO may have an important role in the pathogenesis of ARDS as well as its treatment. NO may be primarily useful in improving matching of ventilation and perfusion in the lung. The aims of the study are to attempt to show that NO will improve oxygenation as evidenced by improvement in PaO2/FiO2. Secondary aims are to see if the improvement in oxygenation allows there to be decreased time on FiO2\>0.60, evaluate whether the order of NO therapy will have any effect on response, and evaluate the characteristics of patients who respond to NO compared to those who do not.
Subjects will be randomized to receive either nitric oxide first (nitric oxide for the first 4 hours, then no intervention/no nitric oxide for the next 4 hours) or delayed treatment with nitric oxide (no intervention/no nitric oxide for the first 4 hours, then nitric oxide for the next 4 hours)..
Blood gases were monitored once an hour during study participation (total of 8 hours). Final PaO2/FiO2 levels will be compared after 8 hours of study treatment in each group.
