Inclusion Criteria:  Children with mild, moderate, and severe ARDS diagnosed according to criteria of Pediatric Acute Lung Injury Consensus Conference (PALICC) in 2015. Children of both sexes aged from one month to 18 years. Children diagnosed with ARDS <48 hours before enrollment  Exclusion Criteria:  Continuous neuromuscular blockade at enrollment Children on phenytoin and carbamazepine Severe liver cirrhosis High-risk medical illness (Bone marrow transplantation within the last one-year, Diffuse alveolar hemorrhage from vasculitis, Chronic respiratory failure, Burns > 70% total body surface) Previous hypersensitivity or anaphylactic reaction to Cisatracurium Neuromuscular conditions that may potentiate neuromuscular blockade and/or impair effective spontaneous ventilation