Résumé
Impedance plethysmographic observations have been compared with arteriographic findings in 216 patients with peripheral arterial occlusive diseases. Impedance plethysmographic diagnosis in these patients was obtained by Parulkar's method without apriori knowledge of arteriographic diagnosis. But for minor discrepancy in the anatomical location of the block in few patients, impedance plethysmographic observations correlated very well with arteriographic findings. Impedance plethysmographic diagnosis was found to be correct in 312, wrong in 53, false negative in 8 limbs respectively, yielding a sensitivity of 97.5% and specificity of 98.1% of this technique.
Sujets)
Adolescent , Adulte , Sujet âgé , Sujet âgé de 80 ans ou plus , Angiographie , Artériopathies oblitérantes/diagnostic , Membres/vascularisation , Femelle , Humains , Mâle , Adulte d'âge moyen , Pléthysmographie d'impédanceRésumé
Impedance Plethysmography technique has been discussed with explanation of two compartment model and parallel conductor theory for the estimation of peripheral blood flow and stroke volume. Various methods for signal enhancement to facilitate computation of blood flow are briefly described. Source of error in the estimation of peripheral blood flow is identified and the correction has been suggested.
Sujets)
Humains , Jambe/vascularisation , Modèles cardiovasculaires , Pléthysmographie d'impédance , Débit sanguin régional/physiologie , Débit systolique/physiologieRésumé
This paper describes the basic methods for measurement of body impedance, electrodes and their configuration, and the measuring instrument with its limitations. A microcomputer assisted impedance plethysmograph system, developed at BARC and different lead configurations for impedance plethysmographic investigation are also described. Typical impedance plethysmographic waveforms recorded from a normal subject and measurement of their amplitude and various time intervals are illustrated.