KIDNEY FUNCTION AND BLOOD PRESSURE

Abstract

According to the filtration-reabsorption theory of kidney function the filtration, i.e., creatinine clearance (F) will be proportional to the pressure available for the filtration (T f) : F = kXT f:= kX (T h[long dash]T c[long dash]T k), where T h is the hydrostatic pressure in the glomeruli, T c the colloid osmotic pressure in the plasma, and T k the hydrostatic pressure within the glomerular capsule. Attempting to verify this hypothesis the filtration was estimated in (1) patients with non-compensated fall of blood pressure after spinal anesthesia, and (2) in patients where the fall of blood pressure was counteracted by injection of ephetonin alone or ephe-tonin + caffeine sodium benzoate prior to or coincident with the administration of the spinal anesthetic. In the first group of expts. was found a marked decrease of the glomerular filtration corresponding fairly well with the fall of blood pressure, and simultaneously a significant increase of the concn. index (concn. of creatinine in urine/concn. of creatinine in blood), indicating a normal or hypernormal tubular function, as far as the re-absorption of water is concerned. In the second group of exps. it was shown that under optimally effective spinal anesthesia the administration of ephetonin is able at the same time to keep up the initial blood pressure and maintain a normal glomerular function. The function of the tubules was not affected by this.