Noninvasive ventilator triggering in chronic obstructive pulmonary disease. A test lung comparison

Area of Science:

• Respiratory Medicine
• Biomedical Engineering

Background:

• Effective noninvasive ventilation (NIV) requires precise synchronization between the ventilator and patient's respiratory cycle.
• Variations in ventilator response times and patient conditions like chronic obstructive pulmonary disease (COPD) exacerbations can impair NIV synchrony.
• Mask leaks and abnormal respiratory mechanics further complicate ventilator-patient interaction.

Purpose of the Study:

• To evaluate the synchronization performance of thirteen different noninvasive ventilation (NIV) ventilators.
• To assess ventilator response times under simulated conditions of acute exacerbations of chronic obstructive pulmonary disease (COPD).
• To quantify triggering delays across various respiratory mechanics and mask leak scenarios.

Main Methods:

• A novel test lung model was developed to simulate diverse COPD exacerbation scenarios, including varying tidal volume (VT), airways resistance (Raw), functional residual capacity (FRC), and mask leak.
• Thirteen NIV ventilators were tested under these simulated conditions.
• Triggering delays were measured from the onset and cessation of the test lung's "inspiration" to the ventilator's response.

Main Results:

• Three ventilators exhibited trigger delays under 120 ms across all tested conditions.
• Most ventilators displayed trigger delays between 120 ms and 300 ms, with some reaching up to 500 ms.
• Simulated variations in respiratory mechanics and mask leak had a generally minor impact on triggering times.

Conclusions:

• Significant variability exists in the synchronization capabilities of current NIV ventilators.
• A subset of ventilators demonstrated superior rapid response, crucial for effective patient-ventilator synchrony.
• Ventilator design appears to be a primary determinant of intrinsic triggering delays, with patient-specific factors having a lesser influence.