The effect of common carotid artery occlusion on blood pressure in the barodenervated cat

Abstract

A 12% blood pressure elevation was found during common carotid occlusion in the barodenervated, thoracotomised cat under Nembutal anaesthesia. This rise in blood pressure appeared to be the net result of an 18% increase of total peripheral resistance and a concomitant 5% decrease of mean aortic flow. When the occlusions were repeated after ganglionic blockade similar values were found, indicating that the increase in resistance had not resulted from reflex vasoconstriction. To test if this increase of total peripheral resistance was caused by a mechanical exclusion, Ohm's law for parallel resistances was applied to the systemic tree to calculate the rise in resistance due to obstruction of the carotid flow. The results thus obtained matched the observed increase of peripheral resistance. It is concluded that common carotid artery occlusion can be used to test completeness of barodenervation in the cat, if an increase in blood pressure of about 12% is allowed for.