Using infrared imaging to assess the severity of pressure ulcers

This study describes the use of infrared thermography to non-invasively assess severity and depth of pressure injuries in dermal and subdermal tissue. Two techniques were investigated: 1) thermographic evaluation of wounds at thermal equilibrium with normal room temperature surroundings, and 2) observation of the temperature changes that occur to the wound area after the application of focal cooling. A series of experiments was performed using a porcine model in which standardized temperature-modulated pressure injuries were assessed by infrared thermography. Wound status (severity and depth) was also determined by histological classification. Correlations were then sought between thermographic data and wound status. Our results showed that deep-tissue injuries may be easily distinguished from shallow wounds by their thermal response to focal cooling. These findings are consistent with a basic schema for heat transfer in deep-tissue injuries that is proposed here. This method is considered to have clinical utility for detecting abscessed areas of skeletal muscle that are concealed by a healthy epidermal or dermal bridge.