SOME BASIC DEFICIENCIES OF THE PLETHYSMOGRAPHIC METHOD AND POSSIBILITIES OF AVOIDING THEM

Journal/Book: Reprinted from ANGIOLOGY Vol. 10 No. 2 April 1959. 1959;

Abstract: . FIGAR M.D.* * Laboratory for Graphical Diagnostics Czechoslovak Academy of Sciences Prague. SUMMARY 1. The author discusses some fundamental deficiencies of photoelectric and electrical plethysmography from the aspect of quantitative registration. He also deals with drawbacks of mechanical plethysmography related to the need for confining the organs under investigation in a sealed chamber with all the ensuing consequences like heat and pressure influences and to insufficient regard for maintaining isotonic conditions in the plethysmographic system. 2. An improved modification of a mechanical water plethysmograph with linear ink recording is described. The tension of the recording membrane remains constant throughout the whole extent of the volume changes and thus ensures isotonic conditions in the plethysmographic system. The inkwriters are simple and give a good recording. 3. A description is given of a principle termed "electrocapacitive plethysmography by which volume changes in the organ under investigation are recorded directly as capacitance changes, without using pneumatic transmission with a pressure capacitance transducer. This dispenses with the need for enclosing the organ in a confined space, and measuring is carried out under physiologic conditions, i.e., without being influenced by temperature or pressure. ___MH

Zurück | Weiter