Reverse Triggering With and Without Breath Stacking During Pressure-Controlled Ventilation: Exposure Burden and Associations With Ventilation Outcomes

Background: Reverse triggering is a complex form of asynchrony with different phenotypes. The exposure burden and clinical outcomes of reverse triggering during pressure-controlled ventilation (PCV) are underexplored. We aimed at determining the incidence of reverse triggering and characterizing the impact of breath-stacking. Methods: This was a prospective, observational analysis. Adult subjects with PCV under long-term monitoring were included. The primary outcome was duration of invasive mechanical ventilation. Secondary outcomes included changes in mechanics and tidal volumes associated with breath-stacking, factors correlated with increased frequency of reverse triggering, and testing for thresholds of volume, which could be associated with harm. Results: Among 429 subjects with PCV and >24 h of usable waveform recording, 174 subjects (40.6%) were found to have reverse triggering, and 80 subjects had reverse triggering with breath-stacking. Reverse triggering with breath-stacking was associated with higher peak inspiratory pressure (PIP) (15.4 [14.3–17.0] versus 13.7 [11.4, 15.0] cm H 2 O, P < .001), driving pressure (ΔP) [8.5(7.5,10.0) versus 7.0(5.8,9.0) cm H 2 O, P < .001] and longer duration of invasive mechanical ventilation [7(3,15) versus 4(2,7) days, P = .015]. Higher level of ΔP (odds ratio [OR] = 1.49, 95% CI: 1.06–2.11, P = .02) and tidal volume (OR = 1.02, 95% CI: 1.01–1.03, P < .001), more fentanyl infusion (OR,1.19, 95% CI: 1.17–1.20, P = .033) and lower value of P aO 2 /F IO 2 (OR = 0.99, 95% CI: 0.98–1.00, P = .02) were risk factors possibly related to reverse triggering with breath-stacking. Receiver operating characteristic analysis suggests that a breath-stacked volume threshold of 141 mL might be associated with prolonged invasive mechanical ventilation. Conclusions: Reverse triggering with breath-stacking during PCV was characterized by higher PIP, ΔP, and longer duration of invasive mechanical ventilation. Larger volumes with breath-stacking may be associated with prolonged mechanical ventilation. Fentanyl usage and worse P aO 2 /F IO 2 were risk factors related to reverse triggering with breath-stacking.