Reverse Trigger Phenotypes in Acute Respiratory Distress Syndrome.

Area of Science:

• Critical Care Medicine
• Respiratory Physiology

Background:

• Reverse triggering is a significant but understudied form of patient-ventilator asynchrony.
• It has critical implications for patients with acute respiratory distress syndrome (ARDS).

Purpose of the Study:

• To identify distinct phenotypes of reverse triggering in ARDS patients.
• To characterize the impact of these phenotypes on tidal volume (Vt) and transpulmonary pressure.

Main Methods:

• Retrospective analysis of 55 ARDS patients on pressure-regulated ventilator modes.
• Phenotypes identified using Campbell diagrams, analyzing breath stacking and respiratory muscle effort.
• Measurements included tidal volumes, respiratory muscle pressure generation, and transpulmonary pressures.

Main Results:

• Reverse triggering detected in 25 patients, with 15 experiencing breath stacking.
• Different phenotypes showed variable inspiratory effort (4-10 cm H2O).
• Specific phenotypes led to increased tidal volumes (88-176 ml) and transpulmonary pressures (2-7 cm H2O), with some causing incomplete exhalation.

Conclusions:

• Reverse triggering exerts diverse physiological effects contingent on its specific phenotype.
• Differentiating these phenotypes is essential for comprehending the clinical consequences of reverse triggering in ARDS.
• Understanding these variations can inform clinical management strategies for ventilator-induced lung injury.