Enhancing the quantification of post-occlusive reactive hyperemia: a multimodal optical approach.

Post-occlusive reactive hyperemia (PORH) is a physiological response marked by a transient increase in microvascular perfusion following ischemia. While cutaneous perfusion during PORH has been extensively characterized using optical approaches such as Doppler-based techniques, low-cost alternatives like photoplethysmography (PPG), videocapillaroscopy (VC) and near-infrared reflectance imaging (NIRI) may provide complementary insights into both microvascular and venous dynamics. However, their role in quantifying PORH remains underexplored.

Quantifying superficial vein morphology with near-infrared imaging during venous congestion.

The venous system plays a key role in clinical practice but remains underassessed due to the limited accessibility of conventional imaging tools. Near-infrared reflection illumination (NIRI) devices ("vein finders"), though recently introduced to assist venipuncture, have potential for broader vascular assessment. Our aim was to investigate the feasibility of a NIRI device to quantify the morphology of superficial hand veins and evaluate their response to a transient hemodynamic stress induced by suprasystolic limb occlusion.

Revisiting the Venoarteriolar Reflex-Further Insights from Upper Limb Dependency in Healthy Subjects.

The venoarteriolar reflex (VAR) is described as a vasoconstriction occurring in response to an increase in venous transmural pressure. Its underlying mechanisms are still not clarified, particularly the neural pathway that supposedly evokes this reflex. In addition, recent studies have shown that the postural maneuvers that evoke VAR also produce a decrease in contralateral perfusion, which is also poorly understood.