![]() With OCTA, the blood flow in the microcirculation of retina and choroid can be evaluated non-invasively, reproducibly and with an automatic analysis at the bedside. Optical coherence tomography angiography (OCTA) is relatively new and has so far been used mainly for high-resolution imaging of the retina and choroid vascularization. However, information about microcirculatory perfusion would be of great interest in intensive care to predict outcome and potentially guide therapy 13, 14. Unfortunately, the analysis of the microcirculation has not yet become established in routine clinical practice, as video microscopy of capillary blood flow has so far been limited by artifacts (e.g., pressure artifacts at the necessary point of contact with the tissue) and time-consuming semi-manual evaluation 11, 12. Hence the demand for bedside methods to monitor the microcirculation.īedside analysis of the microcirculation became possible with the introduction of modern handheld video microscopes using sidestream dark field (SDF) imaging or incident dark field (IDF) illumination technology 8, 9, 10. The aim of hemodynamic therapy should therefore be restoration not only of the macrocirculation but also the microcirculation 7. In such conditions, macrohemodynamic parameters such as cardiac output and perfusion pressure are no longer indicative of perfusion in the microcirculation. A decoupling of macro- and microcirculation (“ loss of hemodynamic coherence”), as can occur, for example, in advanced stages of septic shock is of particular interest here 7. It is known that blood flow in the microcirculation is often impaired in critically ill patients and altered blood flow in the microcirculation is associated with outcome 1, 2, 3, 4, 5, 6. In recent years, research has highlighted the importance of the microcirculation (vessels smaller than 100 μm) in the pathophysiology of diseases and organ dysfunction in critical illness. Comparison of the perfused vessel density between methods showed a plausible level of agreement. This study is the first to demonstrate the suitability of OCTA for evaluating sublingual microcirculation. Analysis according to Bland-Altman revealed a mean bias of 0.95 mm/mm² (95% Confidence interval −1.34 to 3.25) between PVD byOCTA and PVD byIDF with limits of agreement of −5.34 to 7.24 mm/mm². PVD byOCTA did not differ from the PVD calculated from IDF videos (PVD byOCTA 18.6 mm/mm² ) vs. Flow density was automatically extracted from OCTA images (whole en face 48.9% central ring 52.6% ). IDF videos were analyzed following current recommendations. OCTA images were analyzed with regard to flow density and perfused vessel density (PVD byOCTA). Sublingual microcirculation was imaged in 10 healthy volunteers, using an OCTA device and an incident dark field (IDF) illumination microscopy (current gold standard). We investigated the suitability of optical coherence tomography angiography (OCTA) for contactless evaluation of sublingual microcirculation. Evaluation of sublingual microcirculation is not routinely conducted in daily practice due to time-consuming analysis and susceptibility to artifacts. Microcirculatory disorders are crucial in pathophysiology of organ dysfunction in critical illness. ![]()
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