Approach to Patient-Ventilator Asynchrony in the ICU

Immediate Detection and Identification

The American College of Critical Care Medicine recommends examining ventilator waveforms at the bedside to identify the specific type of asynchrony, then systematically adjusting ventilator settings, starting with trigger sensitivity, PEEP, and pressure support, before considering sedation or advanced modes 1
Waveform analysis is the primary diagnostic tool and must be performed continuously to detect asynchrony patterns, with a focus on ineffective triggering, delayed triggering, and other types of asynchrony 1
Ineffective triggering is often caused by intrinsic PEEP, and adjusting trigger sensitivity to the most sensitive setting that doesn't cause auto-triggering can help mitigate this issue 1

The American Thoracic Society suggests switching from pressure triggers to flow triggers to reduce asynchrony incidence and provide better patient comfort, as flow sensors detect changes in machine-produced bias flow and are more responsive to patient effort 1
For patients with obstructive lung disease, setting EPAP/PEEP to 3-5 cm H₂O can help offset intrinsic PEEP and reduce the effort required to trigger breaths, but PEEP should never be set higher than the patient's intrinsic PEEP 1
Prolonging expiratory time can help reduce dynamic hyperinflation and gas-trapping in patients with obstructive lung disease 1
The Society of Critical Care Medicine recommends titrating pressure support incrementally while monitoring comfort and respiratory rate, avoiding excessive pressure support, which can cause hyperventilation during sleep, central apneas, and worsen asynchrony 1

For obstructive lung disease, prioritizing prolonged expiratory time and using modest PEEP (3-5 cm H₂O) to offset intrinsic PEEP can help improve patient outcomes 1
For restrictive disease, achieving adequate tidal volume with relatively low pressures (10-15 cm H₂O) can help improve patient outcomes, while higher pressures may be needed in chest wall disease due to reduced compliance 1
For ARDS, using a low tidal volume strategy (6-8 mL/kg ideal body weight) and applying protective lung ventilation with PEEP 4-8 cm H₂O can help improve patient outcomes, and considering prone positioning for at least 16 hours per day if PaO₂/FiO₂ < 150 mmHg may also be beneficial 1, 2, 3

The American College of Critical Care Medicine recommends titrating sedation according to protocol with regular drug interruption to minimize excessive sedation, and considering short-term neuromuscular blockade (≤48 hours) with cisatracurium for severe ARDS with persistent dyssynchrony despite ventilator adjustments 3
Neuromuscular blockade should be reserved for patients with the most severe ARDS, mainly in the acute phase and during the first 48 hours of mechanical ventilation, as prolonged neuromuscular blockade increases the risk of ICU-acquired weakness 3

The American Association for Respiratory Care recommends checking patient comfort and respiratory rate immediately after any ventilator adjustment, and reassessing waveforms continuously to ensure the intervention resolved the specific asynchrony type 1
Monitoring for subtle asynchronies that may be undetectable without waveform analysis is also crucial 1

The European Respiratory Society suggests limiting oxygen flow rates to ≤4 L/min to prevent mask leak and delayed triggering, promoting asynchrony, and ensuring proper mask fit in non-invasive ventilation to prevent inspiratory effort and end-inspiration from failing detection 1, 4, 5
Using barrier dressings from the outset can help prevent nasal bridge ulceration during prolonged NIV 4, 5