Analysis of blood flow changes in tissue under pressure in order to evaluate the formation of bedsore

Background and Using predictive Criteria of bedsore could be helpful for early diagnosis and prevention of this complication. The aim of this study was to analysis of blood flow changes in tissue under pressure in order to achieve a specific pattern in the formation of bedsore. Blood flow changes in different layers were recorded by an optical system. Blood flow signals were recorded at different ages and time-frequency signals changes were evaluated in pressure -free conditions and also using pressures of 30 and 60 mm Hg in the heel area. Signal analysis was performed by using MATLAB and a significance level of 0. 05 was considered. 15 volunteers (9 men and 6 women) with a mean age of 54 years were evaluated. Based on the records of blood flow، it was noticed that by increasing pressure، the pattern of time- frequency of blood flow changed significantly. Additionally the pattern of time- frequency of blood flow changes showed meaningful changes in relation to the depth of tissue (p<0. 05). Amplitude and frequency of signal content of more than 30 mm Hg of pressure were different compared to the reference case and also to the change in patterns caused by impaired perfusion in the area. A model for the formation of bedsore can be identified by measuring and analyzing of blood flow changes in different layers of tissue and accordingly a new approach to evaluate the behavior of under pressure tissue can be suggested.