A Novel Lumped Parameter Model to Assess Disease Severity in Mechanically Ventilated ARDS Patients

Acute Respiratory Distress Syndrome (ARDS) is a life-threatening lung injury where fluid accumulates in alveoli, causing shortness of breath and restricted blood oxygenation. Mechanical ventilation is the main treatment; however, settings vary with ARDS severity and there is currently no optimal method to determine them. Our aim is to develop a novel lumped parameter model (LPM) for lung to ultimately leverage the ventilator as a diagnostic real-time tool to determine the severity of lung injury at the bedside, based on simple measurements. LPM relied on distinction between three alveoli regions (healthy/unstable but recruitable/damaged alveoli) wherein the relative proportions can be leveraged as the measure of ARDS severity. LPM was implemented in MATLAB & Simulink. Alveoli regions were modeled in distinct RC compartments, and proportions linearly influenced RC components. Proportions estimation framework, using two sets of pressure-flow ventilator measurements, was tested on Control (n=6) and ARDS-model mice (n=6). Promising results were obtained and later verified as proportion of healthy alveoli was much higher in Control compared to ARDS mice, and ARDS mice had a higher proportion of recruitable alveoli, reflecting lung injury. This early-stage, yet promising study, suggests that our novel LPM can successfully discriminate between healthy and ARDS patients based on simple ventilator recordings, highlighting the diagnostic utility of ventilators as hypothesized.