Mechanical ventilation is ubiquitous to intensive care from the neonatal ICU to Adult Critical Care. Lung protective approaches to ventilatory support represent the standard of care and diaphragm protective ventilation is growing in importance. A major challenge in providing state of the art mechanical ventilation is known when to allow the patient to initiate spontaneous breathing and how much effort expended by the patient is “safe.” Critical to the transition toward spontaneous breathing is effective patient ventilator interaction. Discordance or asynchrony occurs when the patient effort and ventilator output are at odds. Recognizing discordance requires pressure and flow waveforms and experience. Discordance occurs during all phases of breath delivery including triggering, breath delivery and cycling. Ventilator settings, respiratory mechanics, muscle function and respiratory drive all conspire to complicate patient ventilator interaction and rendering synchrony a problem. Artificial intelligence may allow detection of discordance and alert caregivers, reducing asynchrony. An asynchrony index of > 10% is associated with prolonged mechanical ventilation and poor outcomes.

This course will demonstrate the most common types of ventilator discordance and methods for mitigation. A process for inspecting pressure and flow tracings for asynchrony will be presented and practiced. The use of esophageal manometry will be reviewed, and determination of patient effort will be described.