1. To access role of vitamin C supplementation in ARDS patients on the following:

   Oxidants/ antioxidants imbalance Length of hospital stay Mortality rate Weaning from mechanical ventilator Incidence of adverse drug reaction

2. To access tolerability of vitamin C supplementation in patients with ARDS.

Acute Respiratory distress syndrome (ARDS) is a form of severe hypoxemic respiratory failure due to severe impairment of gas exchange and lung mechanics that is characterized by inflammatory injury to the alveolar capillary barrier, with extravasation of protein-rich edema fluid into the air space. Current ARDS antioxidant treatment strategy, is based upon supportive therapies including low tidal volume ventilation, fluid management, nutritional support and glucocorticoids.

Ascorbic acid or Vitamin C is an important dietary water-soluble antioxidant, it significantly decreases the adverse effects of ROS such as reactive oxygen and nitrogen species that can cause oxidative damage to macromolecules. Recent studies show that high dose of Vitamin C have protective effects against overwhelming oxidative stress due to critical illness. Vitamin C improves immune function and improves tissue perfusion and reduce tissue hypoxia and subsequent organ dysfunction. Also, Ascorbate, the redox form of vitamin C is physiological antioxidant and has bacteriostatic activity Hence the study aims to evaluate the impact of IV Vitamin C in ARDS, as a novel pharmaceutical approach in an attempt to improve the clinical outcome of ARDS patients, decrease other medications toxicities and improve patients' quality of life.

The objective of the current study was to evaluate the efficacy, safety and tolerability of IV Vitamin C administration in addition to conventional therapy in patients with ARDS by assessing the following:

1. Oxidants/ antioxidants imbalance
2. Length of hospital stay
3. Mortality rate
4. Weaning from mechanical ventilator
5. Incidence of adverse drug reaction
6. Serum IL8 levels

8. Serum Vitamin C levels

Inclusion Criteria:

1. All ARDS cases presenting to the Chest department ICU within 48 hours of diagnosis
2. who don't have an exclusion criteria will be included.

Exclusion Criteria:

1. Known allergy to Vitamin C
2. Inability to obtain consent;
3. Age < 18 years;
4. More than 48 hours since meeting ARDS criteria;
5. Pregnancy or breast feeding,
6. Moribund patient not expected to survive 24 hours;
7. Patients not eligible to CPR
8. Active kidney stone