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International Conference on Mathematical Biology and

Annual Meeting of The Society for Mathematical Biology,

July 27-30, 2009

University of British Columbia, Vancouver

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Program

MSC4b
Darrel Francis
Imperial College London
Title Dynamic therapy of periodic breathing with exogenous carbon dioxide delivered as an inspired gas or endogenously using a cardiac pacemaker: the theoretical potential and the practical challenges.
Abstract For a disease state characterized by oscillatory ventilation, an ideal dynamic therapy would apply a counteracting oscillation in ventilatory stimuli. In my talk I will discuss how this goal might be achieved by either: (a) Dynamically fluctuating FICO2; (b) Modulating respiratory gas transport through the circulation by repetitive alternations in the heart rate, using a cardiac pacemaker, to elicit oscillations in respiratory variables.
I will list some challenges involved in dynamic exogenous CO2 therapy (case a.) and discuss how they might be overcome. This will include examples of simulations of periodic breathing and periodic breathing with automated dynamic interventions. I will provide details of the equipment we are developing which is designed to facilitate this kind of a therapy.
I will then discuss the potential of using pacemaker manipulation to dynamically alter ventilation (case b.). By including acute cardiac output manipulations into an integrated mathematical model of respiratory control, we can see that a rise in cardiac output should yield a gradual rise in end-tidal CO2 and subsequently ventilation. An alternating pattern of cardiac output variation might therefore create oscillations in arterial CO2 and consequently in ventilatory stimuli. I will present clinical data indicating that well timed alteration in cardiac output might really be achievable. I will then discuss the difficulties in converting this kind of intervention into a practical therapy for periodic breathing in heart failure.
LocationWoodward 4