First problem, he is desaturating at 85% despite FiO2 80%. She already increased FiO2 to 100% but that just improved his saturation to 88%.
Increase the mean airway pressure (MAP)
Walk through the break-down tree to figure out how!
2. Increases the mean pressure without increasing the peak pressure
3. Potential issues:
- Alters the I:E ratio (shorter expiration) which may result in gas trapping and barotrauma
- Can cause patient discomfort due to an unnatural breathing pattern
Increasing TV (or Pinsp if you were in PC-AC) isn’t that interesting. You know that high volumes and high pressures can cause additional damage to an already injured lung and your patient is already at 500mL of TV which corresponds to almost 7cc/kg of ideal body weight. You decide not to touch the TV.
Your only other option is therefore to increase Ti. You decide to try it since the patient is now back on sedation and you don’t expect a recovery over night.
In summary, you chose to try PEEP at 8cmH2O (from 5cmH2O) and Ti at 2.0s (from 1.7) to start, knowing you might need to adjust the settings again depending on the evolution overnight.