Acoustical Monitoring of Model System for Vascular Access in Haemodialysis

摘要: Stenosis is the main reason of failure a vascular access in haemodialysis. Its presence engenders an increase morbidity and hospitalization for hemodialysed patients its early detection consists thus important issue. Digital phonoangiography or digital acoustical analysis alternative to current techniques combining advantage low-cost, easy implementation as well user- skill-independency. This technique, automated version auscultatory technique used by practitioners with their stethoscope, based on idea that stenosis modifications hemodynamic at origin sounds “bruits”. study proposed assess influence different parameters acoustics mean vitro model system allows controlling independently each these parameters. Assessed included severity degree stenosis, flow, pressures, viscosity velocity. Results indicated essential parameter was velocity which determines appearance spectral features, starting from value about 1.4 m/s while around 2.6m/s could be almost always associated certitude presence. Spectral features were found frequency bandwidth 70 800Hz three regions located 180-300Hz, 310-390Hz 440-700Hz. Moreover results minimum required, corresponding obstruction lumen vessel least 44%. These suggested underlying modification type flow transitional laminar turbulent state confirmed Reynolds number. also further investigated possibility directly extracorporeal blood circuit transmission through needle.