Methods to Evaluate Airway Resistance and Lung Compliance During Mechanical Ventilation: A Comparative Study

Abstract

Mechanical ventilation is a lifesaving activity that is used in critical care management. In such case, monitoring of airway resistance(Raw) and lung compliance(CL) play a major role for diagnosing the lung condition, setting the ventilator parameters, can act as a decision parameter for weaning the patient from the ventilator. Several methods have been described for estimating these respiratory parameters. In this work, a study is conducted to compare two different methods used to calculate airway resistance and lung compliance during mechanical ventilation. Michigan Adult/Infant lung simulator is used to simulate different compliance conditions and Michigan Pneuflo Resistors to simulate different resistance conditions. Flow, volume and pressure data were logged for different set parameters i.e. for different resistance and compliance combinations. Later these data were used to calculate the respiratory system resistance and compliance. Two methods were used to calculate lung parameters, dynamic approach and Least Square fitting(LSF) method(using respiratory system equation of motion). Both methods gave accurate estimate of Raw and CL. But the dynamic approach required respiratory maneuver whereas LSF approach required large datasets to carry out the calculation and the patient should not show any active breathing during evaluation