Non-invasive assessment of tissue oxygenation parameters in diabetic patients foot sole using near infrared spectroscopy

Background and Objective: Diabetic problems are more common in the lower extremity and linked with high mortality rate which affects public health system. The present study focused on monitoring the changes in tissue oxygenation concentrations using Near infrared spectroscopy system along with temperature and hardness of the foot tissues. Methods: Control subjects (without diabetes) and diabetic patients without neuropathy were selected for this study and three standard foot risk areas were considered. Standard induced ischemic stimulus was given to assess the response of the designed system and to analyze the changes in oxyhemoglobin and deoxyhemoglobin levels during venous occlusion. Results: Results showed significant differences in the tissue oxygenation index value in all three standard areas where oxygenation value at the foot areas were significantly low ( p < 0.05) in diabetic group as compared to control group. Also, significant difference were found in tissue hardness value when comparing between groups, where the diabetic group had significantly high ( p < 0.05) tissue hardness at area 5 and area 8 as compared to control groups. Conclusion: Therefore, the present study concludes that high tissue hardness had significant effect on tissue oxygenation index that affects vascular circulation and this condition could be assessable using NIRS technique in order to find risky areas at the foot sole.