A SIMPLE CAPACITOR TRANSDUCER FOR MEASURING BLOOD PRESSURE IN SMALL EXPERIMENTAL ANIMALS1
Journal/Book: Can. J. Biochem. Physiol. Vol. 38 (1960) S.989-996. 1960;
Abstract: 1Manuscript received April 9 1960. Contribution from the Biological Unit Occupational Health Laboratory Department of National Health and Welfare Ottawa Ontario. 2[Dr. Crevier is deceased June 21 1960.] Abstract A simple capacitor transducer for measuring blood pressure in small experimental animals has been constructed. A hypodermic needle closed at its collar end by a brass diaphragm was used as the cell of the transducer. A thin plastic sheet was used as the dielectric inserted between the diaphragm and a slightly convex brass rod serving as the other plate of the capacitor. The whole assembly constitutes a capacitor whose capacity varies inversely with the pressure as the space between the two plates changes. The transducer can be coupled directly to a conventional R. F. generator preamplifier and pen-writing oscillograph assembly. Results show that this simple transducer is very rugged and has a high degree of zero stability. Its sensitivity is very great accompanied by a very small resolution time. Its accuracy is well demonstrated by the detailed recordings of the central pulse contour in normal and hydralazine-treated rats. . . .