Prediction of inspiratory flow shapes during sleep with a mathematic model of upper airway forces.
OBJECTIVE
To predict the airflow dynamics during sleep using a mathematic model that incorporates a number of static and dynamic upper airway forces, and to compare the numerical results to clinical flow data recorded from patients with sleep-disordered breathing on and off various treatment options.


METHODS
Upper airway performance was modeled in virtual subjects characterized by parameter settings that describe common combinations of risk factors predisposing to upper airway collapse during sleep. The treatments effect were induced by relevant changes of the initial parameter values.


METHODS
Computer simulations at our website (http://www.utu.fi/ml/sovmat/bio/).


METHODS
Risk factors considered in the simulation settings were sex, obesity, pharyngeal collapsibility, and decreased phasic activity of pharyngeal muscles.


METHODS
The effects of weight loss, pharyngeal surgery, nasal continuous positive airway pressure, and respiratory stimulation on the inspiratory flow characteristics were tested with the model.


RESULTS
Numerical predictions were investigated by means of 3 measurable inspiratory airflow characteristics: initial slope, total volume, and flow shape. The model was able to reproduce the inspiratory flow shape characteristics that have previously been described in the literature. Simulation results also supported the observations that a multitude of factors underlie the pharyngeal collapse and, therefore, certain medical therapies that are effective in some conditions may prove ineffective in others.


CONCLUSIONS
A mathematic model integrating the current knowledge of upper airway physiology is able to predict individual treatment responses. The model provides a framework for designing novel and potentially feasible treatment alternatives for sleep-disordered breathing.
Aittokallio
Tero
T
Biomathematics Laboratory, Turku Centre for Computer Science and Department of Mathematics, University of Turku, Turku, Finland. tero.aittokallio@utu.fi
Gyllenberg
Mats
M
Saaresranta
Tarja
T
Polo
Olli
O
D001143:Arousal / Q000502:physiology; D005260:Female; D006801:Humans; D007320:Inspiratory Capacity / Q000502:physiology*; D008297:Male; D008962:Models, Theoretical; D012307:Risk Factors; D012895:Sleep, REM / Q000502:physiology*; D014584:User-Computer Interface