The Gravity-VAP (Ventilator-Associated Pneumonia) Trial

Inclusion Criteria: 1. Age ≥ 18 years 2. Patients expected to be oro-tracheally intubated for at least 48 hours or longer 3. Enrollment time window within 12 hours following intubation Exclusion Criteria: 1. Current and past participation in an other intervention trial conflicting with the present study 2. Previous endotracheal intubation longer than 12 hours during the previous 30 days 3. Patients with documented bronchiectasis 4. Cystic fibrosis 5. Witnessed pulmonary aspiration either prior or at intubation 6. Patients with increased intracranial pressure, brain edema; or medical conditions that can worsen with increase in intracranial pressure 7. Patients with significant heart failure and activity impairment (Class III-IV of the New York Heart Association (NYHA) 8. Spinal cord injury 9. BMI \> 35, or weight above 300 pound 10. Grade IV Intra-abdominal pressure: IAP \> 25 mmHg or abdominal compartment syndrome , defined as a sustained IAP \> 20 mmHg that is associated with new organ dysfunction / failure 11. Pregnancy 12. Orthopedic problems that will not allow the patient to be kept in one of the study positions