Assessment of the Pathophysiology of Injured Tissue With an In Vivo Electrical Injury Model

Tissue destruction from electrical injury is devastating and hard to treat. Unfortunately, the pathophysiology of electrical trauma is still not well understood. We have developed a suite of tools aimed at investigating damage due to high voltage shock on the skin using a rat model. Electrical injuries were created with a custom made high-tension shock system and a spectroscopic system, based on spatial frequency domain imaging, was used to determine optical properties of electrically injured tissues. The extrapolated values of absorption and scattering coefficients at six different wavelengths were then utilized to monitor parameters of interest such as tissue oxygen saturation, methemoglobin volume fraction, and hemoglobin volume fraction at four time intervals post injury. An FLIR thermal camera was used to record skin temperature during the electrical shock. Finally, a laser Doppler imaging apparatus was used to assess tissue perfusion. In this paper, the results of experiments conducted on a rat model and discussions on the systemic changes in tissue optical properties before and after electrical shock are presented. A reduction in tissue oxygen saturation postinjury is observed as well as an increase in methemoglobin. Tissue perfusion increases immediately after the delivery of the electrical shock.