Mathematical model of the human respiratory system in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a respiratory illness with high rates of morbidity and mortality. The human respiratory system undergoes many chronic changes and adaptations under this disease conditions. The purpose of this study was to devise a mathematical model of the human respiratory system under COPD. The model presented is based on a previous detailed model of the human respiratory system. Cyclic changes of the lung volume with the effects of increased dead space are included and the lung mechanics are used to adjust the rate of breathing. Continuous and dynamic changes in the cardiac output and cerebral blood flow are represented in the model. The model includes the modified response of the respiratory control system under the chronic effects of COPD including the shifting of the acid-base balance under the disease conditions. The performance of the model has been examined at rest and during moderate exercise with and without oxygen supplementation. The results under different stimuli are found to be in general agreement with experimental observations.