Mechanically ventilated patients scheduled to undergo a CT scanning for their routine clinical care
More than 24 hours of mechanical ventilation
Less than 15 days of mechanical ventilation if patient presents ALI/ARDS (in order to exclude the late, fibrotic, stage of ARDS)
Group 2
Mechanically ventilated patients with a diagnosis of sepsis
Less than 96 hours of mechanical ventilation
You may not be if
Age less than 18 years
Hemodynamic instability, defined as: systolic blood pressure (SBP) \< 90 mmHg that is not adequately stabilized by vasopressors or inotropic agents. For these purposes, SBP will not be considered "adequately stabilized" if the dose of the vasopressor/inotrope has not been stable for at least one hour
Hypoxemia, defined as: PaO2 \< 70 mmHg on an inspired oxygen fraction (FiO2) greater than or equal to 0.9; FiO2 greater than or equal to 0.8 at baseline
Hemodynamic and/or respiratory instability (as defined, respectively, in 2 and 3), that develop when the patient is mobilized during routine nursing care such as repositioning/washing the patient or changing their bed linens
Hemodynamic and/or respiratory instability (as defined, respectively, in 2 and 3), that develop when a 15-25 second respiratory pause is introduced as per the study protocol. This will be tested by inducing such a pause prior to transporting the patient
Patients must be deemed by the treating clinical staff to be able to tolerate leaving the ICU for 90 minutes (40-60 minute imaging time + 30 minute safety margin). Treating MD, RT, and RN must all agree that the patient is stable for transport
Any acute or chronic condition which, in the opinion of the investigator, might confound the imaging measurements (such as, but not limited to, severe bronchospasm, pulmonary infection, and lung tumor)
