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 cardiorespiratory system. In this
model, we present the cardiorespiratory 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, 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 of the simulation
results reveals that the changes in airway resistance have a broad
impact on the human cardiorespiratory system and that the pulmonary
circuit is stressed beyond normal under hypoxic environments in most
COPD patients.