<qa>  What is the aim of the study?The use of neuromuscular blocking agents NMBA in ARDS patients has not been extensively investigated. It has been recently demonstrated that a systematic 48-h infusion of NMBA is associated with a significant improvement in oxygenation as compared with a control group Gainnier et al., Crit Care Med 2004. Moreover, a trend towards a reduction in the mortality rate has been observed. The aim of the study is to show a reduction of the mortality rate of ARDS patients. 