This paper presents a non-contact and cost-effective method to assess venous hemodynamics along the lower limbs using photoplethysmography imaging (PPGI). Seventeen healthy volunteers performed the venous muscle pump test, inducing venous blood volume changes in their lower legs, which were recorded using a webcam. PPGI signals were extracted from three regions along the lower leg. Key parameters derived from a physiological model were evaluated and analyzed statistically: perfusion amplitude, ejection time constant, and peripheral venous flow index. The method demonstrated robust estimation of physiologically explainable parameters, and the potential to improve venous function diagnostics with high spatial resolution.

• Publikační typ
• časopisecké články MeSH

Cardiorespiratory coordination (CRC) probes the interaction between cardiac and respiratory oscillators in which cardiac and respiratory activity are synchronized, with individual heartbeats occurring at approximately the same temporal positions during several breathing cycles. An increase of CRC has previously been related to pathological stressful states. We studied CRC employing coordigrams computed from non-contact photoplethysmography imaging (PPGI) and respiratory data using the optical flow method. In a blocked study design, we applied the cold pressure test (CPT), water at ambient temperature (AWT), and intermittent resting conditions. In controls (no intervention), CRC remained on initial low levels throughout measurements. In the experimental group (AWT and CPT intervention), CRC decreased during AWT and CPT. Following both interventions, CRC increased significantly, with a rebound effect following AWT. In controls, HR increased steadily over time. CPT evoked a significant HR increase which correlated with subjective stress/pain ratings. The CRC increase following AWT correlated significantly with subjective pain (r = .79) and stress (r = .63) ratings. Furthermore, we observed a significant correlation (r = - .80) between mean RMSSD and mean duration of CRC, which further supports an association between autonomic state and CRC level. CRC analysis obtained from cutaneous tissue perfusion data therefore appears to be a sensitive and useful method for the study of CRC and ANS activity. Future studies need to investigate the physiological principles and clinical significance of these findings.

• MeSH
• autonomní nervový systém * MeSH
• bolest MeSH
• fotopletysmografie * MeSH
• klinická relevance MeSH
• lidé MeSH
• srdce MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH