The investigators aim to demonstrate that use of transpulmonary pressure to guide PEEP management is safe in patients with possible elevations of intracranial pressure.
Purpose: To establish safety of titrating PEEP based on transpulmonary pressure as measured by an esophageal balloon in mechanically ventilated neurosurgical patients. Participants: Adult patients admitted to the Neuro ICU at UNC Hospital and requiring mechanical ventilation who have an intracranial pressure monitoring device in place. Procedures (methods): All enrolled patients will have esophageal balloons placed with measurement of transpulmonary pressures. All patients will have baseline measurements recorded of intracranial pressure, cerebral perfusion pressure, and cerebral autoregulation. PEEP will then be titrated based on transpulmonary pressure measurements with recording of physiological measurements over the next hour. At the conclusion of the hour, all patients will be returned to their prior ventilator settings.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
OTHER
Masking
NONE
Enrollment
1
Pressures \[Esophageal Pressure (Pes), Airway Pressure (Paw), and Transpulmonary Pressure (Ptp)\] are measured directly through the ventilator. The waveforms of Paw, Pes, and Ptp will be visualized on the ventilator. Ptp is obtained from Paw - Pes. All patients will have baseline measurements recorded of ICP, CPP, and MAP. PEEP will be increased on the ventilator to achieve a Ptp between 0 and +2 cm H2O ("Optimal PEEP"). Measurements of Intracranial pressure (ICP), cerebral perfusion pressure (CPP), and mean arterial pressure (MAP) will be repeated 5 minutes after the change in PEEP.
University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States
Change in ICP Value
The Intracranial pressure (ICP) value after intervention will be considered equivalent to the ICP before intervention if the 95% upper bound of the change is lower than the non-inferiority margin of 4 mm Hg.
Time frame: Within 5 minutes of catheter placement
Change in Cerebral Perfusion Pressure (CPP)
Cerebral perfusion pressure is equal to the mean arterial pressure (MAP) minus the intracranial pressure (ICP). The initial CPP is calculated by measuring CPP immediately before changing ventilator settings. The post-intervention CPP is measured 5 minutes after ventilator setting change is made. The difference between the initial CPP and the post-intervention CPP reflects the change in CPP.
Time frame: Immediately before and 5 minutes after ventilator setting change
Change in Mean Arterial Pressure
Mean Arterial Pressure (MAP) is the average arterial pressure in one cardiac cycle measured through an arterial line.
Time frame: Immediately before and 5 minutes after ventilator setting change
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