A STADY OF THE IMPEDANCE PLETHYSMOGRAPHY ON THE KIDNEY

Abstract

It was possible to record the renal impedance plethysmogram (RIP) by our method using needle electrodes inserted into the kidney. Many variable factors influenced upon the pattern and the amplitude of the RIP and it was often difficult to obtain the same recording even in the same kidney under similar condition. Therefore the quantitative evaluation was questionable.
However, relatively stable recording could be obtained for 5-10 minutes, and in this stable period it was possible to observe the change of RIP induced by various loads which affected the intrarenal hemodynamics.
1) Following the intravenous (i. v.) administration of adrenaline the amplitude of RIP begun to decrease in 10 to 15 seconds and became almost zero 2 minutes after, but returned to the previous amplitude several minutes after.
2) Following the i. v. administration of papaverin, the amplitude of RIP begun to increase in 10 to 15 seconds, and reached its maximum several minutes after, and returned to the previous amplitude about 10 minutes after.
3) Gradual decrease of the RIP amplitude was induced by the progressive compression of the renal artery, and it decreased remarkably when the blood flow reached to the level less than 50% of the original value measured by electromagnetic flowmeter. When the renal blood flow decreased to the level less than 20%, the RIP faded away. When the compression was released, RIP returned to almost the previous state.
4) By the uniform compression of the renal vein the RIP amplitude changed indefinitly increased, remained unchanged, or decreased; that is, definite reaction pattern could not be observed.
5) By acute elevation of intrapelvic pressure of the autotransplanted kidney to femoral site the amplitude of RIP decreased and returned to previous level after lowering the intrapelvic pressure.
6) Diminished amplitude of RIP produced by the elevated intrapelvic pressure was increased by the i. v. administration of papaverin.