Mathematical model for the hemodynamic response to venous occlusion measured with near-infrared spectroscopy in the human forearm.
We propose a mathematical model to describe the hemodynamic changes induced by a venous occlusion in a human limb. These hemodynamic changes, which include an increase in blood volume, a reduction in blood flow, and modifications to the oxygen saturation of hemoglobin, can all be measured noninvasively with near-infrared spectroscopy (NIRS). To test the model, we have performed NIRS measurements on the human forearm, specifically on the brachioradialis muscle, during venous occlusion induced by a pneumatic cuff inflated around the upper arm to pressures within the range 10-60 mmHg. We have found a good agreement between parameters measured by NIRS (total hemoglobin concentration and hemoglobin saturation) and the corresponding model parameters (capacitor voltage and arterial/capillary branch current). In particular, model and experiment indicate that the time constant for blood accumulation during venous occlusion (approximately 73-79 s) is much slower than the time constant for blood drainage following cuff release (approximately 5 s). These results indicate that this mathematical model can be a valuable analytical tool to characterize, optimize, and further develop diagnostic measurement schemes that use venous occlusion approaches.
Vo
Toi Van
TV
Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA.
Hammer
Peter E
PE
Hoimes
Matthew L
ML
Nadgir
Shalini
S
Fantini
Sergio
S
D000222:Adaptation, Physiological / Q000502:physiology; D000465:Algorithms; D001783:Blood Flow Velocity / Q000502:physiology*; D003198:Computer Simulation; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D005542:Forearm / Q000098:blood supply / Q000502:physiology*; D006801:Humans; D008955:Models, Cardiovascular; D010092:Oximetry / Q000379:methods*; D010991:Plethysmography / Q000379:methods*; D014680:Veins / Q000502:physiology*; D014690:Venous Pressure / Q000502:physiology*