Reverse triggering in patients with acute brain injury undergoing controlled ventilation.

Area of Science:

• Critical Care Medicine
• Respiratory Physiology
• Neurology

Background:

• Reverse triggering (RT) is a ventilatory asynchrony where respiratory muscles activate during passive mechanical insufflation.
• RT can potentially worsen lung injury, but its occurrence in acute brain injury (ABI) patients is not well understood.
• This study investigates RT incidence and associated factors in ABI patients.

Purpose of the Study:

• To determine the incidence of reverse triggering (RT) in patients with acute brain injury (ABI).
• To identify factors associated with RT in this specific patient population.
• To explore the predictive value of specific respiratory mechanics parameters for RT phenotypes.

Main Methods:

• Retrospective analysis of waveform data from ABI patients on controlled mechanical ventilation.
• RT identification via airway pressure, flow, and esophageal pressure waveforms.
• Calculation of RT incidence as the ratio of RT breaths to total breaths.

Main Results:

• RT occurred in 17.7% of datasets (8.4% of breaths) across 53 patients.
• Mid-cycle RT (61.1%) was the most common phenotype, followed by breath stacking (16.6%).
• Independent predictors of RT included combined opioid/sedative use, lower Sedation-Agitation Scale (SAS) scores, reduced airway delta pressure, and minimal respiratory rate discrepancies. P0.1 predicted breath stacking (AUC 0.72).

Conclusions:

• Deep sedation, lower airway delta pressure, and synchronized ventilator/patient respiratory rates are associated with RT in ABI.
• P0.1 is a reliable predictor for breath stacking, a specific type of RT.
• Understanding these factors can help mitigate RT and improve outcomes in mechanically ventilated ABI patients.