Control analysis of blood flow in the microcirculation: Normal vs. sickle cell disease states
Published laser doppler studies of blood flow revealed the existence of low frequency flow oscillations for patients with sickle cell disease, but not in normal individuals. The objective of this research was to determine a mechanism for such oscillations if they exist, based on the hypothesis that low frequency oscillations can occur in capillary beds as a result of interactions of oxygen saturation dependent rheology, oxygen metabolism, flow mechanics and control features. These features were modeled using non-set point control theory and compared to raw patient data from the published studies. Low frequency oscillations were demonstrated for both normal individuals and patients with sickle cell disease, in both model simulations and raw patient data. It is indicated by the model that the precapillary clog condition produces the low frequency oscillations and may be a compensatory mechanism in sickle cell control. The metabolic rate was the primary contributing factor in controlling low frequency oscillation period. Viscosity was a factor in determining the onset of oscillations. In addition, viscosity is the primary contributor to the length of time flow is on during the period. Examination of raw data in comparison to the output from the model indicates that the low frequency oscillations are real. Applications of the model concepts to the analysis of the clinical data revealed, that contrary to the published reports, oscillations did occur in normals as well as patients with sickle cell disease. Thus, low frequency oscillations are a real component of capillary blood flow under appropriate conditions of metabolism and rheology.
Cecchini, Albert Babb Piccard, "Control analysis of blood flow in the microcirculation: Normal vs. sickle cell disease states" (1991). Dissertations available from ProQuest. AAI9211919.