Assessment of oxygenation with polarized light spectroscopy enables new means for detecting vascular events in the skin.

INTRODUCTION: Impaired oxygenation in the skin may occur in disease states and after reconstructive surgery. We used tissue viability imaging (TiVi) to measure changes in oxygenation and deoxygenation of haemoglobin in an in vitro model and in the dermal microcirculation of healthy individuals. MATERIALS AND METHODS: Oxygenation was measured in human whole blood with different levels of oxygenation. In healthy subjects, changes in red blood cell concentration (CRBC,TiVi), oxygenation (DeltaCOH,TiVi) and deoxygenation (DeltaCDOH,TiVi) of haemoglobin were measured during and after arterial and venous occlusion using TiVi and were compared with measurements from the enhanced perfusion and oxygen saturation system (EPOS). RESULTS: During arterial occlusion, CRBC,TiVi remained unchanged while DeltaCOH,TiVi decreased to -44.2 (10.4) AU (p=0.04), as compared to baseline. After release, CRBC,TiVi increased to 39.2 (18.8) AU (p<0.001), DeltaCOH,TiVi increased to 38.5. During venous occlusion, CRBC,TiVi increased to 28.9 (11.2) AU (p<0.001), DeltaCOH,TiVi decreased to -52.2 (46.1) AU (p<0.001) compared to baseline after 5min of venous occlusion. There was a significant correlation between the TiVi Oxygen Mapper and EPOS, for arterial (r=0.92, p<0.001) and venous occlusion (r=0.87, p<0.001), respectively. CONCLUSION: This study shows that TiVi can measure trends in oxygenation and deoxygenation of haemoglobin during arterial and venous stasis in healthy individuals.