J Med Syst
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Comparative Study
The advantages of wearable green reflected photoplethysmography.
This report evaluates the efficacy of reflected-type green light photoplethysmography (green light PPG). Transmitted infrared light was used for PPG and the arterial pulse was monitored transcutaneously. The reflected PPG signal contains AC components based on the heartbeat-related signal from the arterial blood flow and DC components, which include reflectance and scattering from tissue. ⋯ Also, the DC components for green light PPG were similar during heat stress, but showed less signal output for infrared light PPG during hot exposure. The main reason for the reduced DC components was speculated to be the increased blood flow at the vascular bed. Therefore, reflected green light PPG can be useful for pulse rate monitoring because it is less influenced by the tissue and vein region.
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Blast-induced neurotrauma (BINT) is a common injury associated with the present military conflicts. Exposure to the shock-wave produced from exploding ordnances leads to significant neurological deficits throughout the brain and spinal cord. Prevention and treatment of this injury requires an appropriate understanding of the mechanisms governing the neurological response. ⋯ Our findings suggest an inverse relationship between the magnitude of the shock-wave overpressure and the degree of functional deficits using a double sucrose gap recording chamber. Similar correlations are drawn between overpressure and degree of anatomical damage of neuronal processes using a dye-exclusion assay. The following approach is expected to significantly contribute to the detection, mitigation and eventual treatment of BINT.