Patient-Ventilator Dyssynchrony Incidence
Patient-ventilator dyssynchrony occurs in 24% of mechanically ventilated critically ill patients overall, with specific types varying: double triggering affects 13% of patients, flow starvation 10%, and when using computerized detection algorithms, dyssynchrony is identified in 3-34% of all breaths depending on the population studied. 1, 2
Overall Incidence Rates
The reported incidence of patient-ventilator dyssynchrony varies significantly based on detection methodology and patient population:
- Overall dyssynchrony: 24% of mechanically ventilated episodes in mixed ICU populations 1
- Breath-by-breath analysis: 3-34% of all breaths show dyssynchrony when computerized waveform interpretation is used 2
- High dyssynchrony burden: Defined as >10% of all breaths showing dyssynchrony, this severe pattern occurs in a subset of patients and is associated with 67% hospital mortality versus 23% in those without frequent dyssynchrony 2
Specific Dyssynchrony Types and Their Frequencies
Most Common Types
Double triggering is the most prevalent form, occurring in 13% of mechanically ventilated patients, followed by flow starvation at 10% 1. These two patterns are particularly concerning because they deliver large tidal volumes >10 mL/kg in 54% and 11% of affected breaths respectively, compared to only 0.9% in synchronous breaths 2.
Other Documented Types
- Ineffective triggering: Common but specific incidence varies by detection method 3, 4
- Delayed triggering: Frequently observed but precise percentage not consistently reported 3, 5
- Premature cycling: Occurs regularly during assisted ventilation 3, 4
- Delayed cycling: Another common pattern during the expiratory phase 3, 5
- Autotriggering: Less common but clinically significant 3, 5
Detection Method Impact on Reported Incidence
The detection methodology dramatically influences reported incidence rates 6. Manual waveform interpretation by healthcare staff has suboptimal performance with many events going undetected 4. Computerized algorithms detect dyssynchrony with an area under the receiver operating curve >0.80, revealing much higher incidence rates than manual detection 2.
The most sensitive detection involves simultaneous recordings of diaphragm electrical activity and esophageal pressure changes, though this is not routinely available in clinical practice 6, 7.
Population-Specific Risk Factors Affecting Incidence
Certain patient populations experience higher dyssynchrony rates:
- Smoking history: Increases risk of overall dyssynchrony and double triggering 1
- Pneumonia, sepsis, or ARDS: All significantly increase dyssynchrony incidence 1
- Ventilation mode: Pressure-targeted ventilation decreases dyssynchrony occurrence compared to volume-targeted modes 1
- Specific ventilator settings: During volume-controlled synchronized intermittent mandatory ventilation, particular settings correlate with increased dyssynchrony 1
Clinical Significance of Incidence
Dyssynchrony is not merely a technical problem but directly impacts patient outcomes 1, 2. The number of overall dyssynchrony events, particularly double triggering and flow starvation, correlates with worse outcomes and fewer hospital-free days 1. Frequent dyssynchrony (>10% of breaths) increases hospital mortality from 23% to 67% 2.
Critical Monitoring Implications
Every mechanically ventilated patient requires continuous waveform assessment to identify specific asynchrony types 6. The high incidence rates—affecting nearly one-quarter of all ventilated patients—mandate that clinicians maintain vigilance throughout the entire duration of mechanical ventilation 4. Current practice falls short, as many dyssynchrony events go undetected without systematic monitoring 4.