METHOD FOR EVALUATING FUNCTIONAL STATE OF LUNGS Russian patent published in 2002 - IPC

FIELD: medicine. SUBSTANCE: method involves recording temperature changes in inhaled and exhaled gas mixture by means of temperature pickups set on the way of gas flow during the whole respiratory cycle, its duration and exhaled air volume. Heat quantity released in breathing is calculated by means of formula where Q_E is the mean quantity of released heat in cal, C is the mean heat capacity of air in temperature interval from 20 to 40 C in cal/g/K, ρ is the mean air density in g/cm³, V is the exhale air volume in ml, t₁-t₂ is the respiratory cycle duration in s and T is the respiratory mixture temperature in C. EFFECT: high accuracy of noninvasive method; enabled quantitative estimation.