ALIVE
Assessing Lung Inhomogeneity During Ventilation for Acute Hypoxemic Respiratory Failure
Study Investigators
Dr. Jose Dianti (jose.dianti@uhn.ca)
Dr. Ewan Goligher (ext. 6810, ewan.goligher@uhn.ca)
Study Contact
Jenna Wong (ext. 7613, jenna.wong@uhn.ca)
Samira Fard (samira.fard@uhn.ca)
Study Summary
Prospective observational study aiming to characterize the effect of different strategies for titrating positive end-expiratory pressure (PEEP) on ventilator-induced lung injury in patients with ARDS.
Study Population
40 mechanically ventilated patients with acute (equal to or less than 7 days) hypoxemic respiratory failure (P/F ratio ≤ 200 mm Hg) with bilateral airspace opacities on chest radiograph or CT.
Study Objectives
Evaluate the impact of an individualized PEEP titration strategy based on EIT on mechanisms of VILI in comparison to a conventional PEEP titration strategy.
Compare the optimal PEEP levels identified by several different PEEP titration strategies.
Evaluate the utility of the oxygenation response to PEEP to assess lung recruitment.
Study Interventions
The study team (including MD and RRT) will sedate and paralyze the patient and adjust mechanical ventilation settings throughout the protocol to ensure limits are met. Patients will be monitored using esophageal pressure and electrical impedance tomography and the findings will be continuously recorded. Once baseline measurements are obtained, various PEEP strategies are implemented and compared. The optimal PEEP values selected from these strategies will be used to determine improvement in oxygenation and ultimately predict lung recruitability.
Why it Matters
PEEP is a complex and controversial aspect of the management of mechanical ventilation and ARDS. In addition to improving oxygenation, a key role of PEEP is to minimize VILI. However the optimal PEEP likely varies widely between patients, depending on the level of lung recruitability (among other factors). A variety of techniques for titrating PEEP have been proposed, but it remains unclear which technique is most effective to reduce VILI. Limiting the application of high PEEP to patients with significant recruitability may improve patient outcome; the oxygenation response to PEEP might provide a feasible means of assessing lung recruitability, but prospective confirmation is required.