FIELD: medicine.
SUBSTANCE: CO2 index is calculated by formula CO2=tgα/tgβ, where α - angle of inclination of the mixed expiratory curve, β angle of inclination of alveolar plateau and Van Marten's index RCO2 by formula RCO2=Re+r1, Re - the radius of the exponential part of capnogram, r1 - the radius of the curving passage of descendent curve to horizontal line; γ - angle between continuing lines of the ascendant arm of capnogram and alveolar plateau. The respiratory cycles are used with such capnogram curve, where the ratio between expiration phase and duration of respiratory cycle is not less than 0.5, the amplitude of incisors at the alveolar plateau is not more than 5% of maximal concentration of inspired carbon dioxide at the analysed part of capnogram, the relative difference of maximal concentration of inspired carbon dioxide in previous and following cycles doesn't exceed 10%. The summing probability index of obstruction K is calculated by formula K=(K1+K2+K3)/3, where K1=19 - CO2 index, K2=(RCO2-0.5)x30; K3=γ-103, and if K>1 the conclusion is made regarding obstructive abnormalities of the external respiration.
EFFECT: diagnostic precision is achieved.
1 exc precision is achieved.
