Abstract
Background:
Plateau pressure (Pplat) is routinely monitored during mechanical ventilation to assess the risk of ventilator-induced lung injury. Although Pplat is classically measured during controlled ventilation with a constant-flow pattern, it is increasingly applied during decelerating flow modes and in the presence of spontaneous respiratory effort. Uncertainty persists regarding the accuracy of Pplat for determining static respiratory system compliance (CRS) and the inspiratory hold duration required to obtain reliable measurements across varying flow patterns, levels of effort, and lung conditions.
Methods:
We conducted a combined bench and clinical study. Using an ASL 5000 lung simulator, we compared measured versus set CRS across 3 pediatric age ranges, simulated lung conditions, levels of inspiratory effort, and 3 ventilation modes (volume-controlled continuous mandatory ventilation, pressure-controlled continuous mandatory ventilation with adaptive targeting, and pressure support ventilation) and determined the time required to achieve steady Pplat. In parallel, we performed a secondary analysis of airway pressure waveforms from children with pediatric ARDS enrolled in a lung- and diaphragm-protective ventilation trial to define the minimum inspiratory occlusion time required for reliable Pplat measurement during passive and spontaneous breathing.
Results:
Across all bench conditions, CRS derived from driving pressure and tidal volume (VT) slightly overestimated set CRS (median bias 0.09 mL/cm H2O/kg [95% CI 0.06–0.16]). Bias increased with greater inspiratory effort, without meaningful differences among ventilation modes after stratification by effort. Time to steady Pplat increased progressively with higher effort (passive 0 [0–400] ms; moderate: 300 [200–400] ms; high: 500 [380–800] ms; P < .001). In patient data, steady Pplat was achieved within 500 ms under passive conditions but exceeded 1,500 ms during high effort.
Conclusions:
During both constant and decelerating flow modes of ventilation, Pplat combined with VT and PEEP provided a reliable measure of CRS. However, as spontaneous respiratory effort increases, the time to achieve a steady Pplat was prolonged, and CRS derived from Pplat may be overestimated.
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Supplementary Material
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