Respiratory mechanics modifies the impact of ventilator settings on clinical outcome in patients with acute brain injury.

Authors

Domenico Luca Grieco, Alessandro Stronati, Chiara Robba, Tommaso Rosà, Ida G Iavarone, Emanuele Rezoagli, Filippo Bongiovanni, Antonio M Dell'Anna, Alessandro Cardu, Francesca Graziano, Stefania Galimberti, Anselmo Caricato, Nicolò Patroniti, Fabio Silvio Taccone, Giuseppe Citerio, Massimo Antonelli

Published in

Intensive care medicine. Aug 19, 2026. Epub Aug 19, 2026.

Abstract

To investigate whether respiratory system elastance (E_RS) modifies the associations of tidal volume (V_T) and respiratory rate with clinical outcomes in mechanically ventilated patients with acute brain injury.
In this post hoc analysis of the VENTIBRAIN study, E_RS was computed as the ratio of driving pressure (ΔP) to V_T/PBW. Effect modification by E_RS on outcome associations was assessed.
In 1158 patients, V_T was similar across E_RS tertiles (median 7.9, 7.6 and 7.1 mL/kg), resulting in a marked ΔP gradient across tertiles (median 5, 9, and 12 cmH₂O). Higher V_T was associated with lower ICU mortality in patients with low E_RS (OR 0.52, 95%CI 0.36-0.74) but not in those with high E_RS (OR 1.16, 95% CI 0.89-1.51; P_int < 0.001). Higher respiratory rate was associated with worse outcomes, particularly at low E_RS, with the association attenuating at higher E_RS. The Bayesian optimal V_T/PBW decreased continuously with E_RS, from 11.4 mL/kg at E_RS 0.5 cmH₂O/(mL/kg) (≈ ΔP 6 cmH₂O) to 4.4 mL/kg at E_RS 2.5 cmH₂O/(mL/kg) (≈ ΔP 11 cmH₂O), while the optimal respiratory rate increased from 15 to 19 breaths/min. At constant alveolar ventilation, 1-cmH₂O ΔP increase had comparable prognostic impact to ≈ 3 breaths/min respiratory rate increases. These results were consistent irrespective of ARDS diagnosis.
The impact of ventilator settings is modulated by E_RS. A physiological framework for V_T adjustment could consider ΔP along with the respiratory rate required to maintain isocapnia, with outcome effects governed by a trade-off of ≈ 3 breaths/min per 1-cmH₂O change in ΔP.

PMID:
42618770
Bibliographic data and abstract were imported from PubMed on 20 Aug 2026.

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