The indices of lang ventilation and biomechanics of breathing were det
ermined in 48 patients with chronic obstructive bronchitis (COB) aged
60-79 and 45 healthy subjects of the same age. Inpatients with COB a r
ise of lung ventilation, work of breathing, ventilation equivalent, po
sitive reaction to oxygen, a decrease of maximal breathing capacity an
d reserve of breathing take glace that reflect excessive and uneffecti
ve ventilation. limitation of its functional performance. These specif
ic features are due to increase in tile total lung capacity at the exp
ense of residual volume against a decrease of vital capacity with dimu
nition of alveolar ventilation to lung ventilation ratio. But of decis
ive significance was desturbance of bronchial patency manifesting in a
decrease of Tiffeneau index, midexpiratory flow, respiratory flows in
forced respiration. especially in expiratory phase, concavity of now-
volume curve to volume axis, a rise of bronchial resistance.