• Hospital Mortality
  

• Mortality attributed to respiratory failure
  
• Duration of respiratory failure and duration of mechanical failure
  
• Evaluation of respiratory function during mechanical ventilation
  
• Incidence of barotraumas
  
• Non-respiratory organ dysfunction
  

To compare an innovative Lung Open Ventilation strategy with a proven low tidal volume strategy, hypothesizing that the Lung Open Ventilation strategy may reduce mortality, other organ dysfunction, and the duration of mechanical ventilation, intensive care, and hospital stay.

Inclusion Criteria:

• Invasive mechanical ventilation
• Acute respiratory insufficiency (within past 28 days)
• Bilateral infiltrates on frontal chest radiograph
• Hypoxemia, defined as PaO2/FiO2<=250

Exclusion Criteria:

• Primary cause of respiratory failure is cardiac
• Anticipated duration of mechanical ventilation < 48 hours
• Inability to wean other experimental ventilation strategies
• Severe chronic respiratory disease
• Neuromuscular disease that will prolong mechanical ventilation
• Conditions where hypercapnia-induced intracranial hypertension should be avoided
• Morbid obesity (> 1Kg per cm body weight)
• Pregnancy
• Very unlikely to survive and lack of commitment to life support Underlying irreversible condition with 6 month mortality >= 50%
• Greater than 48 hours elapsed since first eligible
• Current participation in competing trial
• Lack of physician, patient or proxy consent