Note on the blood-pressure changes following reduction of the renal arterial circulation

Abstract

Of the various workers who have studied the effects of reduction of kidney substance, only Pässler and Heineke record systematic blood-pressure observations. They were able to make direct measurements in the femoral on five dogs before and after operation, and reported a rise in pressure in all, the smallest increase being 15 mm., the greatest 29 mm., and the average 21.5 mm. These figures are based on the comparison of single readings before operation with one or more after operation, and are open to the objections I have previously urged. Because of the small number of reported observations in this field, I hope to be pardoned for presenting my still very incomplete studies at this time, in order that I may demonstrate one of the animals now living with reduced kidney substance and hypertension.

I have made blood-pressure readings, by the rough method previously described, on twenty-three dogs, over a period of fifteen months. As a guide to normal readings in the dog I have figures from twelve dogs that were in good health, several of these being finally checked by direct carotid tracings. In these twelve dogs the average pressure, calculated from a number of readings on each, lay between 91 and 119 mm., the highest individual reading being 130 mm., and the lowest 85 mm. A number of observations made before operation on the ten nephrectomized dogs showed an average blood-pressure between 90 and 117 mm.; highest reading was 135 mm., lowest 80 mm. These readings average lower than those obtained in man, but the method as applied to the dogs is more comparable to the results of Gärtner in man, since the artery used is more peripheral, and the pressure within it more subject to fluctuations due to variations in local vasomotor tone. As I have already said, however, the errors are all on the side of too low readings; therefore, with a sufficient number of pre-operative readings to give a fair average, the finding of a marked rise in blood-pressure subsequently cannot be attributed to errors inherent in the method.