ASSESSING TISSUE PERFUSION IN SHOCK AND SEPSIS WITH DARK FIELD SIDE-STREAMMICROSCOPY

摘要

The microcirculation, comprised of arterioles, capillaries and venules < 100 um in diameter, is an important but often overlooked entity in critical illness. Macrovascular parameters (heart rate, pulse quality, blood pressure, lactate etc.) are oftenused to assess tissue perfusion, however it is well established that macrovascular parameters do not always equate with local microvascular changes. With states of shock, systemic inflammatory response syndrome, and sepsis, despite adequate blood flow through the macrovascular system, blood flow through the capillaries can become heterogeneous. Due to dysregulation of arterioles governing flow at the arteriole end of capillaries, microthrombosis, increased leukocyte adhesion, and increased permeabilitysome capillaries can have good blood flow while neighboring capillaries may have poor to no blood flow. Therefore, methodologies such as orthogonal polarization spectral (OPS) imaging and its successor, side-stream dark field microscopy (SDF), have founda niche in research settings to assess microcirculation in patients with sepsis and shock, and evaluate response to various therapeutic interventions. With further advancements in technology and ongoing research, it seems very plausible that microcirculatory assessment as a point of care test in clinical settings is not far off.