[Pendelluft volume during double-triggered asynchronous breaths under pressure support ventilation: a prospective...

Area of Science:

• Critical Care Medicine
• Respiratory Physiology
• Mechanical Ventilation

Background:

• Double-triggering, a common patient-ventilator asynchrony during pressure support ventilation (PSV), can lead to ineffective ventilation.
• The pendelluft phenomenon, characterized by abnormal air movement within the lungs, is a potential consequence of respiratory mechanics.
• Understanding the relationship between double-triggering and pendelluft is crucial for optimizing mechanical ventilation strategies.

Purpose of the Study:

• To investigate the association between double-triggering and the pendelluft phenomenon in patients receiving PSV.
• To quantify the pendelluft volume during normal breaths, double-triggered breaths, and breaths following double-triggering.
• To compare pendelluft volumes and respiratory parameters between patients with severe and non-severe double-triggering.

Main Methods:

• A prospective observational study involving 40 postoperative patients on invasive mechanical ventilation with PSV.
• Electrical impedance tomography (EIT) was used to monitor global and regional lung impedance changes.
• Pendelluft volume was measured using EIT data, and patients were categorized based on double-triggering frequency.

Main Results:

• Double-triggering occurred in 2.3% of analyzed breaths, with high interobserver reliability for detection.
• Pendelluft volume was significantly increased during double-triggered breaths and the subsequent breath compared to normal breaths.
• Severe double-triggering was associated with higher pendelluft volumes and respiratory rates, but not significant differences in clinical outcomes.

Conclusions:

• Double-triggering during PSV is strongly linked to the pendelluft phenomenon, particularly during the double-triggered breath itself.
• The severity of the pendelluft phenomenon escalates with the frequency of double-triggering.
• Higher pendelluft volumes during normal and double-triggered breaths, along with elevated respiratory rates, are indicators of severe double-triggering.