Trigger performance of mid-level ICU mechanical ventilators during assisted ventilation: a bench study

Area of Science:

• Mechanical Ventilation
• Respiratory Care Engineering

Background:

• Intensive care unit (ICU) mechanical ventilators are crucial for respiratory support.
• Mid-level ICU ventilators aim to provide essential functions at a lower cost.
• Understanding their triggering performance is vital for patient safety and effective ventilation.

Purpose of the Study:

• To compare the triggering performance of mid-level ICU mechanical ventilators against a standard ICU mechanical ventilator.
• To identify differences in ventilator response under various simulated respiratory conditions.

Main Methods:

• An experimental bench study was conducted using a computerized mechanical lung model (IngMar ASL5000).
• Ten mid-level ICU ventilators were tested against one standard ICU ventilator.
• Comparisons were made across two lung model effort levels, three respiratory mechanics (normal, COPD, ARDS), and two ventilation modes (volume and pressure assist/control).

Main Results:

• Ventilator triggering performance varied significantly.
• Only half of the mid-level ventilators achieved a mean inspiratory trigger time under 100 ms.
• Most mid-level ventilators exhibited longer inspiratory delay times and less comparable pressure drops during triggering than the standard ICU ventilator.
• Expiratory settling time showed the highest variability among tested ventilators.

Conclusions:

• Significant triggering performance differences exist between mid-level ICU ventilators and standard ICU ventilators.
• Certain mid-level ventilators demonstrated inferior triggering responses, particularly under high inspiratory effort conditions.
• These ventilators may not adequately support patients with high ventilatory demands compared to standard ICU ventilators.