Abstract
The research goal was to formulate and substantiate the hypothesis explaining support for an expiratory air flow in case of pulmonary emphysema. The research method consisted in comparing the mechanical properties of lungs in practically healthy individuals (37 individuals, mean age – (30.4 ± 1.7) y.o.) and COPD patients with pronounced lung emphysema (30 patients, mean age – (52.1 ± 2.3) y.o.) as well as those of isolated normal lungs (n = 14) and isolated lungs of patients who died of COPD (n = 5). Pulmo-nary mechanics was studied via the simultaneous measurement of transpulmonary pressure and lung ven-tilation volume. General lung hysteresis and elastic lung hysteresis were calculated. The mechanical properties of isolated lungs were studied using passive ventilation under the Donders bell. The air flow was interrupted in order to measure alveolar pressure and develop an elastic lung hysteresis curve. Pres-sure in the Donders bell was changed by means of a special pump in automatic and manual modes. The research has not revealed any fundamental differences between the mechanical properties of the normal and emphysematous lungs. A minimum increase in the pressure inside the Donders bell over atmospheric pressure used to stop air ejection in both normal and the emphysematous lungs as the result of flap-valve bronchial obstruction. In living beings, air is ejected from lungs with an increase in pressure under the conditions of forced expiration. Pressure increases up to (38.6 ± 2.71) cm H2O in healthy individuals and up to (20.5 ± 1.86) cm H2O in COPD patients. Probably, an expiratory air flow is supported by active expiratory bronchial dilatation that counteracts flap-valve bronchial obstruction. The hypothesis is based on the confirmed ability of the lungs to perform inspiratory actions (in addition to the action of respiratory muscles) and the theory of mechanical lung activity.
Highlights
The research method consisted in comparing the mechanical properties of lungs in practically healthy individuals (37 individuals, mean age – (30.4 ± 1.7) y.o.) and COPD patients with pronounced lung emphysema (30 patients, mean age – (52.1 ± 2.3) y.o.) as well as those of isolated normal lungs (n = 14) and isolated lungs of patients who died of COPD (n = 5)
The air flow was interrupted in order to measure alveolar pressure and develop an elastic lung hysteresis curve
The research has not revealed any fundamental differences between the mechanical properties of the normal and emphysematous lungs
Summary
МЕХАНИЗМЫ ПРОТИВОДЕЙСТВИЯ КЛАПАННОЙ ОБСТРУКЦИИ БРОНХОВ ПРИ ОБСТРУКТИВНОЙ ЭМФИЗЕМЕ ЛЕГКИХ Тетенев К.Ф., Тетенев Ф.Ф., Агеева Т.С., Бодрова Т.Н., Карзилов А.И., Месько П.Е. Цель исследования – сформулировать и обосновать гипотезу, объясняющую поддержку экспираторного потока воздуха при эмфиземе легких. При минимальном повышении давления в колоколе Дондерса сверх атмосферного изгнание воздуха прекращалось как в нормальных, так и в эмфизематозных легких в результате срабатывания клапанной обструкции бронхов. Преимущественное же увеличение неэластической фракции работы дыхания на вдохе, по сравнению с работой дыхания на выдохе, противоречило представлению о преимущественном значении экспираторного сужения бронхов в нарушении биомеханики дыхания при обструктивной эмфиземе легких. Увеличение длительности выдоха по сравнению с длительностью вдоха при эмфиземе способствовало снижению скорости экспираторного потока воздуха и снижению экспираторной фракции неэластической работы дыхания за счет торможения выдоха. Цель исследования – сформировать и обосновать гипотезу, объясняющую поддержку экспираторного потока воздуха при эмфиземе легких
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