A model of the effects of fluid variation due to body position on Cheyne-Stokes respiration.

Cheyne-Stokes respiration is a distinct breathing pattern consisting of periods of hyperpnea followed by apnoeas, with unknown aetiology. One in two patients with congestive heart failure suffers from this condition. Researchers hypothesize that key factors in CSR are the fluid shift from the standing to supine position and the differences between genders. A mathematical model of the cardiorespiratory system was constructed using parameter values from real data. Hopf bifurcation analysis was used to determine regions of steady versus oscillatory breathing patterns. In the model, Cheyne-Stokes respiration is more likely to occur while in the supine position and males are more likely to develop Cheyne-Stokes than females. These findings, which are in agreement with clinical experience, suggest that both gender and fluid shift contribute to the pathogenesis of Cheyne-Stokes respiration and that physical quantities such as blood volumes and neural feedback may be sufficient to explain the observations of CSR.