Abstract
BACKGROUND: To develop and validate classifier models that could be used to identify patients with a high percentage of potentially recruitable lung from readily available clinical data and from single CT scan quantitative analysis at intensive care unit admission. 221 retrospectively enrolled mechanically ventilated, sedated and paralyzed patients with acute respiratory distress syndrome (ARDS) underwent a PEEP trial at 5 and 15 cmH(2)O of PEEP and two lung CT scans performed at 5 and 45 cmH(2)O of airway pressure. Lung recruitability was defined at first as percent change in not aerated tissue between 5 and 45 cmH(2)O (radiologically defined; recruiters: Δ(45-5)non-aerated tissue > 15%) and secondly as change in PaO(2) between 5 and 15 cmH(2)O (gas exchange-defined; recruiters: Δ(15-5)PaO2 > 24 mmHg). Four machine learning (ML) algorithms were evaluated as classifiers of radiologically defined and gas exchange-defined lung recruiters using different models including different variables, separately or combined, of lung mechanics, gas exchange and CT data. RESULTS: ML algorithms based on CT scan data at 5 cmH(2)O classified radiologically defined lung recruiters with similar AUC as ML based on the combination of lung mechanics, gas exchange and CT data. ML algorithm based on CT scan data classified gas exchange-defined lung recruiters with the highest AUC. CONCLUSIONS: ML based on a single CT data at 5 cmH(2)O represented an easy-to-apply tool to classify ARDS patients in recruiters and non-recruiters according to both radiologically defined and gas exchange-defined lung recruitment within the first 48 h from the start of mechanical ventilation.