Effects of acute acid-base changes on renal hemodynamics in anesthetized dogs

¹ Cedars-Sinai Medical Research Institute, and Departments of Medicine and Physiology, University of California Medical Center, Los Angeles, California

Renal hemodynamics were studied in 58 experiments during acid-base disturbances in anesthetized dogs. Renal blood flow was measured with an electromagnetic flowmeter on the left renal artery. Arterial pressure was also measured and renal vascular resistance calculated. Flow and resistance were measured during respiratory acidosis and alkalosis, metabolic acidosis and alkalosis, and combined respiratory and metabolic acid-base disturbances such that arterial pH was maintained normal while pCO₂ changed. pH changes were approximately 0.2 unit above and below normal and pCO₂ changed to approximately double or half control. Renal vascular resistance was shown to be pCO₂ dependent but not pH dependent. Doubling the control pCO₂, whether pH changed or remained constant, resulted in decreased resistance (–16%) while decreasing pCO₂ to approximately one-half normal resulted in increased resistance (+17%). Resistance was not influenced by the degree of renal denervation resulting from the use of the flowmeter. Changes in resistance appear likely to be related to local rather than central factors.

Key Words: acid base • renal blood flow • respiratory acidosis • circulation • pH

Submitted on May 10, 1965