From the Guidelines
Ventilator dyssynchrony occurs when a mechanical ventilator's timing or delivery of breaths doesn't match a patient's respiratory efforts, creating a mismatch between the patient and the machine, and is a common problem that affects approximately 25% of ventilated patients, leading to increased work of breathing, patient discomfort, prolonged mechanical ventilation, and potentially worse outcomes. There are several types of dyssynchrony, including:
- Trigger dyssynchrony (when the ventilator fails to detect patient effort)
- Flow dyssynchrony (when delivered flow doesn't match patient demand)
- Cycle dyssynchrony (improper timing of breath termination)
- Double triggering (multiple ventilator breaths for a single patient effort) Management typically involves adjusting ventilator settings such as sensitivity, flow rate, inspiratory time, and mode selection based on the specific type of dyssynchrony, as seen in studies such as 1. For example, increasing trigger sensitivity can help with trigger dyssynchrony, while adjusting flow rates can address flow dyssynchrony. In some cases, sedation adjustments may be necessary, though the goal should be to optimize ventilator settings first, as noted in 1 and 1. Proper recognition and management of ventilator dyssynchrony is essential for patient comfort and optimal respiratory support, and can help reduce morbidity, mortality, and improve quality of life, as emphasized in 1. It is also important to consider the use of neuromuscular blockade and other strategies to improve oxygenation and reduce ventilator-associated lung injury, as discussed in 1 and 1. Overall, the management of ventilator dyssynchrony requires a comprehensive approach that takes into account the individual patient's needs and circumstances, and is guided by the latest evidence and clinical guidelines, such as those outlined in 1 and 1.
From the Research
Definition of Ventilator Dyssynchrony
- Ventilator dyssynchrony is defined as a mismatch between the patient's respiratory efforts and mechanical ventilator delivery 2.
- It occurs when either the initiation and/or termination of mechanical breath is not in time agreement with the initiation and termination of neural inspiration, respectively, or if the magnitude of mechanical assist does not respond to the patient's respiratory demand 3.
- Ventilator dyssynchrony can be described as the inappropriate timing and delivery of a mechanical breath in response to patient effort, which may cause ventilator-induced lung injury (VILI) 4.
Types of Ventilator Dyssynchrony
- Trigger dyssynchrony (ineffective efforts, autotriggering, and double triggering) 2.
- Flow dyssynchrony, which happens during the inspiratory phase 5, 2.
- Cycling dyssynchrony (premature cycling and delayed cycling) 2.
Detection and Clinical Relevance
- Ventilator dyssynchrony can be detected by carefully scrutinizing the airway pressure-time and flow-time waveforms displayed on the ventilator screens along with assessing the patient's comfort 3, 2.
- Computerized interpretation of ventilator waveforms can detect ventilator dyssynchrony with an area under the receiver operating curve of >0.80 4.
- Ventilator dyssynchrony has been associated with patient outcomes, including increased hospital mortality 4.