Location: Fields Institute , 222 College Street, Toronto

February 27, 2009 - 3:30pm
Bill Langford
University of Guelph
AUDIO AND SLIDES

Models of Cheyne-Stokes Respiration with Cardiovascular Pathologies

Cheyne-Stokes respiration is a periodic breathing pattern, characterized by short intervals of very little or no breathing (apnea) each followed by an interval of very heavy breathing (hyperpnea). This work expands on previous mathematical models of the human cardio-respiratory system, simulating the factors that determine the concentration of carbon dioxide in compartments of the cardiovascular system and lungs. The parameter boundary on which Hopf bifurcation gives birth to a stable CSR oscillation has been determined. The model predicts that the onset of Cheyne-Stokes oscillations may result from an increase in any of: ventilation-perfusion ratio, feedback controller gain, transport delay, left heart volume, lung congestion or cardiovascular efficiency. Clinically, it is known that Cheyne-Stokes respiration is more likely to occur in people with cardiopulmonary pathologies such as chronic heart failure, pulmonary edema or encephalitis, and also in healthy humans during acclimatization to high altitudes or after hyperventilation. The model gives plausible physical explanations for each of these observations.
This work is joint with Fang Dong of Dalian, China.