A Comparative Study on Estimated Methods for Airway Resistance and Lung Compliance in Air Breath Circuit
摘要
Airway resistance ( \({R}_{aw}\) ) and airway compliance ( \({C}_{aw}\) ) are pivotal in diagnosing pulmonary conditions and optimizing mechanical ventilator settings. In this paper, a comparison of estimation lung methods is carried out to reveal the well-suited method for applying ventilator titrate, achieving accuracy control efforts. The paper employs methodologies for estimating lung parameters, including the static, the least squares, the expiratory time constant, and the numerical method. Each method leverages data from the respiratory system’s operation, encompassing airflow, pressure, and volume, to estimate the airway’s \({R}_{aw}\) and \({C}_{aw}\) . Notably, as each method operates on distinct theoretical principles and computational algorithms, ensuring fairness in their comparison necessitates unanimity experimental test conditions. The Bag-Valve-Mask ventilator, Continuous Mandatory Ventilation-Volume Control mode, usage of the same pseudo-lung, and adherence to identical experimental durations and sampling times across all estimation methods are maintained in all experimental implementations. Under the same experimental test conditions with a tidal volume of 500 ml and using IngMar lung simulator ( \({R}_{lung}\) = 20 cmH2O/l/s, \({C}_{lung}\) = 20 ml/cmH2O), the relative error of \({R}_{aw}\) between a static method and dynamic methods, including the least square, time constant, and numerical method, are 11.6%, 13.4%, and 14.28%, respectively. Correspondingly, those of \({C}_{aw}\) are 8.96%, 12.12%, and 13.05% in turn. The results demonstrate a higher performance of the least square method in comparison with other dynamic methods. The paper assesses the error between dynamic methods and static methods in determining \({R}_{aw}\) and \({C}_{aw}\) . Hence, the results are crucial for modeling prosthetic lungs and controller design in mechanical ventilators.