Mohammadmostafa Asheghan, PhD
Mohammadmostafa Asheghan*, Emma Roussel, Bradford Smith, Farhad R. Nezami
Farhad R. Nezami
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.
We built an electrical circuit mimicking lungs properties which modeled three possible lung regions, i.e. healthy, unstable and damaged zones, relative size of each directly related and determined ARDS severity. It is possible to deduce proportions of each zone based on patient’s ventilator measurements, easily acquired at the bedside. Translating this novel tool to the clinical setting will tremendously help physicians to leverage the ventilator as a diagnostic tool for ARDS severity and continuously optimize ventilator settings in a patient-specific manner, thereby reducing ventilator-induced lung injury and leading to faster patient recovery.