Coda Change APRV and what's new in mechanical ventilation
Feb 15, 2024
Dive into the mechanics of APRV, where pressure control meets innovative ventilation strategies. Discover how it creates intrinsic PEEP, encouraging spontaneous breathing while minimizing sedation. Learn about its potential benefits for hypoxemia and lung protection, and explore evidence from animal studies and RCTs highlighting its advantages. Luke Torre discusses concerns around transpulmonary pressures and the need for more human research. Rethink conventional settings to boost mean airway pressure and optimize patient care.
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APRV As Pressure‑Control With Inverse I:E
- APRV is essentially pressure-control ventilation with extreme inverse I:E ratios to increase time at higher pressure.
- It deliberately uses long T-high and very short T-low to raise mean airway pressure and allow spontaneous breathing.
Intrinsic PEEP From Short Releases
- APRV holds the lung at a high pressure for most of the cycle creating intrinsic PEEP despite P-low sometimes set to zero.
- On pressure modes flow stops when alveolar pressure equals set pressure, so repeated small expirations don't produce uncontrolled stacking.
Set T‑Low By Expiratory Termination
- Set P-high and P-low plus T-high and T-low rather than conventional inspiratory pressure and inspiratory time.
- Use expiratory termination (~75% of peak expiratory flow) or auto-release to tune T-low instead of fixed timings.