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Effect of Cardiogenic Oscillations on Trigger Delay During Pressure Support Ventilation
Glauco M Plens1, Caio Ca Morais1, Maria A Nakamura1
1Divisao de Pneumologia, Instituto do Coracao, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brazil.
Respiratory Care
|June 14, 2018
Summary
To improve ventilator response, sensitive triggers are used, but this risks auto-triggering caused by cardiogenic oscillations. Less sensitive triggers are needed to prevent auto-triggering, though this increases delay, impacting patient-ventilator synchrony.
Area of Science:
- Critical Care Medicine
- Respiratory Physiology
- Biomedical Engineering
Background:
- Ventilator trigger sensitivity is crucial for response time but can cause auto-triggering.
- Auto-triggering, often due to cardiogenic oscillations, leads to patient-ventilator asynchrony.
- Cardiogenic oscillations are cyclical pressure/flow variations from cardiac contractions.
Purpose of the Study:
- To evaluate the trigger performance of 5 ICU ventilators.
- To assess the ability of ventilator triggers to abolish auto-triggering.
- To analyze the impact of cardiogenic oscillations on trigger function.
Main Methods:
- A mechanical breathing simulator tested 5 ICU ventilators.
- Simulated cardiogenic oscillations (0-1 cm H2O) were applied.
- Trigger response time, pressure drop, work of breathing, and auto-triggering proportion were measured.
Main Results:
- Increased cardiogenic oscillations correlated with higher auto-triggering rates.
- Less sensitive triggers were required to avoid auto-triggering.
- Less sensitive triggers increased time delay and work of breathing.
Conclusions:
- A trade-off exists between trigger sensitivity and auto-triggering.
- Less sensitive triggers are necessary to prevent auto-triggering in the presence of cardiogenic oscillations.
- Optimizing ventilator trigger settings requires balancing response time and asynchrony.
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