From the Guidelines
Autotriggering can indeed lead to elevated peak pressure in mechanical ventilation, as it causes the ventilator to deliver breaths asynchronously with the patient's natural respiratory rhythm, resulting in breath stacking and increased intrathoracic pressure. According to the most recent and highest quality study available, 1, the management of mechanical ventilation should prioritize minimizing auto-PEEP and dynamic hyperinflation, which can be achieved by adjusting ventilator settings such as tidal volume, respiratory rate, and inspiratory-to-expiratory ratio.
Key Considerations
- Autotriggering can cause several ventilator-related complications, including increased peak airway pressures, which can lead to barotrauma, hemodynamic compromise, and patient discomfort.
- To address autotriggering, clinicians should adjust ventilator sensitivity settings, check for circuit leaks, manage excessive water in the circuit, and consider adjusting PEEP levels, as suggested by 1.
- In some cases, sedation adjustments may be necessary if patient movement is contributing to false triggers, and the use of controlled ventilation modes combined with deeper levels of sedation may be required to achieve a more prolonged expiratory phase.
Management Strategies
- The BTS/ICS guideline for the ventilatory management of acute hypercapnic respiratory failure in adults recommends a low tidal volume strategy, with tidal volumes of 6-8 mL/kg, and a respiratory rate of 10-15 breaths per minute, to minimize dynamic hyperinflation and auto-PEEP 1.
- The guideline also suggests that allowing permissive hypercapnia, with a pH above 7.2, can be well tolerated and may reduce the risk of ventilator-induced lung injury.
- Intrinsic PEEP should be offset by increasing the ventilator PEEP to reduce the effort of triggering and prevent ineffective triggering and patient discomfort, as noted in 1.
From the Research
Autotriggering and Elevated Peak Pressure
- Autotriggering can have deleterious effects, including diaphragmatic atrophy, increased duration on the mechanical ventilator, and increased stay in the intensive care unit 2.
- The presence of asynchrony, which includes autotriggering, has been shown to have deleterious effects on patients, including duration of mechanical ventilation and increased length of hospital stay 3.
- Autotriggering caused by cardiogenic oscillation during flow-triggered mechanical ventilation can lead to respiratory alkalosis and hyperinflation of the lungs, which may result in elevated peak pressure 4.
- The use of automatic triggering and cycling systems, such as Auto-Trak, may affect patient-ventilator synchrony and comfort, but its impact on peak pressure is not directly addressed 5.
- There is no direct evidence in the provided studies that autotriggering leads to elevated peak pressure, but it can cause other complications that may indirectly affect peak pressure 2, 3, 4.