Patients in an intensive care unit (ICU) as a result of injuries resulting from penetrating or non-penetrating trauma who are intubated and receiving invasive mechanical ventilation who also have one or more of the following: 1. Traumatic brain injury 2. > 1 long bone fractures 3. Shock on arrival in the Emergency Department (systolic BP < 90 mmHg) 4. Lung contusion 5. Receipt of > 6 units of blood

1. Inability to obtain consent from the patient or his/her legally authorized representative (LAR) 2. Unwillingness of the treating physician to use sigh ventilation as all treating physicians must have equipoise with respect to the intervention 3. Age limitations per Institutional Review Board regulations 4. Undergoing invasive mechanical ventilation for > 24 hours, excluding any time during which the patient was being ventilated in the operating room, CT or IR, as this could represent too long a delay in instituting the intervention for it to have a chance of being effective 5. Presence of malignancy or other irreversible disease or condition for which the six month mortality is estimated to exceed 50% (e.g., chronic liver disease with a Child-Pugh Score of 10-15, malignancy refractory to treatment) as this could affect the clinical course and cloud interpretation of the endpoints 6. Women who are pregnant (negative pregnancy tests required on women of child-bearing age) per Human Subjects regulations 7. Prisoners, per Human Subjects regulations 8. Neurological condition that could impair spontaneous ventilation (e.g., C5 or higher spinal cord injury as this could affect the clinical course and cloud interpretation of the ventilator-free day endpoint 9. Lack of availability of Dräger Evita Infinity V500 ventilator as this is the only ventilator capable of delivering sigh breaths as described in the protocol 10. Burns > 40% of body surface area as this could affect the clinical course and cloud interpretation of the endpoints 11. Treating physicians being unwilling to use low VT ventilation strategy when ARDS is diagnosed as low VT ventilation is now considered standard of care for patients with ARDS. 12. Moribund, not expected to survive 24 hours as this could affect the clinical course and cloud interpretation of the endpoints13. Treating physician's decision to use airway pressure release ventilation (APRV). 13. Patient not expected to require mechanical ventilation > 24 hours (e.g., intubated for alcohol intoxication rather than pulmonary problem).