Chronic Obstructive Pulmonary Disease (COPD) is a progressive lung disease
characterized by airflow limitation. This study develops a systems engineering
framework for representing important mechanistic details of COPD in a model of
the cardio-respiratory system. In this model, we present the cardio-respiratory
system as an integrated biological control system responsible for regulating
breathing. Four engineering control system components are considered: sensor,
controller, actuator, and the process itself. Knowledge of human anatomy and
physiology is used to develop appropriate mechanistic mathematical models for
each component. Following a systematic analysis of the computational model, we
identify three physiological parameters associated with reproducing clinical
manifestations of COPD - changes in the forced expiratory volume (FEV), lung
volumes, and pulmonary hypertension. We quantify the changes in these
parameters (airway resistance, lung elastance, and pulmonary resistance) as the
ones that result in a systemic response that is diagnostic of COPD. A
multivariate analysis reveals that the changes in airway resistance have a
broad impact on the human cardio-respiratory system, and that the pulmonary
circuit is stressed beyond normal under hypoxic environments in most COPD
patients.Comment: 25 pages, 15 figure