Application of Electroimpedance Spirometry for Clinical Assessment of Respiratory Function Indices

A practical method of studying the dynamics of respiratory function associated with the registration of the electrical impedance of conductive biological fluids exhaled by the patient is described. In the model measuring cell, the physical causes and relationships in the conductivity of the air flow, saturated with an electrolytic fluid aerosol created by an ultrasonic nebulizer have been investigated experimentally. The design of a new electrical impedance spirometer in the form of a mouthpiece with electrical sensors, filled with a porous medium impregnated with electrolyte, through which the patient breathes, is developed and tested. To register fluctuations in the magnitude of the impedance modulus, an original hardware and software complex is used, made on the basis of a high-speed analog-to-digital converter. Based on electrical impedance analysis data, the methods are proposed for quantitative assessment of the basic spirometric medical indicators characterizing the state and functioning of the patient's breathing apparatus, such as respiration rate, entry and expiration rate, exhaled air volume, amount and concentration of exhaled lung fluid.