Effect of Intrathoracic Pressure Regulation on Decreased Cerebral Perfusion

Inclusion Criteria: - ≥18 years of age - intubated and mechanically ventilated on a volume controlled mode - head injury or other intracranial pathology and compromised cerebral perfusion - arterial line in place or alternative with continuous pressure monitoring - SpO2 ≥90% - mean arterial pressure >55 - admission to ICU or about to undergo neurosurgery with planned placement of an invasive intracranial pressure monitor - inclusion presents no significant delays to planned emergent neurosurgery - prior written informed consent Exclusion Criteria: - cardiac or pulmonary injury - confirmed pneumothorax or hemothorax - serious neck injury resulting in neck swelling with jugular venous compression - evidence of ongoing uncontrolled bleeding - respiratory disease such as COPD, interstitial lung disease, or other parenchymal or pulmonary vascular disease - marked hypertension at time of device use defined as systolic blood pressure >180 mmHg - congestive heart failure - women with positive serum or urine pregnancy test or breast feeding