Pressure injuries are skin lesions commonly caused by constant tissue compression, making them a public health challenge. In this context, technological resources such as thermography can provide additional information for analyzing blood perfusion in lesions. Therefore, this study aimed to investigate the estimation of blood perfusion in pressure injuries, using the Pennes Equation from a thermal image to understand the dynamics of blood perfusion in the region of choice. Thermographic images were collected from three bedridden individuals at a referral hospital in Curitiba as a methodology. Two patients had a pressure injury (one with a stage 2-E2 injury and the other with a stage 3-E3 injury), and one patient had no injury (SL). Statistical analysis was done using the R software, the Pennes equation, the T student, and multiple regression tests. The results showed significant differences between the perfusion rates, with a null value for perfusion in the individual without injury and positive perfusion values for the individual in stage 2 \((\hat{\omega }= +0.01023)\) , indicating an improvement in perfusion. For the individual in stage 3 \((\hat{\omega }= -0.000272)\) , the value was negative, indicating lower perfusion. It can be concluded that the analysis indicated a substantial reduction in blood flow as the injury progressed. The importance of a multidimensional approach to assessing perfusion, as well as the Pennes Equation, for a more objective assessment of the prognosis of these patients is highlighted.