Affiliations: Department of Trauma and Plastic Surgery, University of Regensburg, Regensburg, Germany | Department of Dermatology, University of Regensburg, Regensburg, Germany | Department of Radiology, University of Regensburg, Regensburg, Germany
Note: [] Corresponding author: PD Dr. Lukas Prantl, MD, PhD, Department of Trauma and Plastic Surgery, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany. Tel.: +49 941 944; Fax: +49 941 944; E-mail: lukas.prantl@klinik.uni-regensburg.de.
Abstract: A sufficient oxygen supply in skin grafts requires a functioning microcirculation. Venous occlusion impairs the microcirculation and is therefore a major threat of healing. Luminescence life time imaging (LLI) enables the non-invasive and two-dimensional assessment of the transcutaneous oxygen partial pressure (ptcO2). In the current trial this new device was applied for monitoring of venous congestion. A tourniquet on the upper arm was inflated up to 40–50 mmHg and released after 10 min in eight healthy volunteers. The ptcO2 was measured at the lower arm every minute prior to, during and up to 10 min after cuff occlusion (40°C applied skin temperature) using LLI of platinum(II)-octaethyl-porphyrin immobilized in a polystyrene matrix. For validation the polarographic Clark electrode technique was applied in close proximity and measurement was performed simultaneously. ptcO2 measurements prior to (Clark: 50.68±5.69 mmHg vs. LLI: 50.89±4.96 mmHg) and at the end of the venous congestion (Clark: 16.41±4.54 mmHg vs. LLI: 23.82±3.23 mmHg) did not differ significantly using the Clark electrode vs. LLI. At the initial congestion respectively reperfusion phase the Clark electrode measured faster decreases respectively increase of ptcO2 due to oxygen consumption of this method. This experimental trial demonstrates the applicability of LLI to quantify the ptcO2 under changing venous blood flow. The use of planar transparent sensors allows the non-invasive generation of two-dimensional maps of surface pO2 what makes this method particular suitable for monitoring of skin grafts.
Keywords: Transcutaneous pO_2, luminescence life time imaging, Clark electrode
