An experimental study of the blood flow in the common carotid artery and vertebral artery

Abstract

Recent advancement of neck dissection made the field of operation wider into larger vessels of the neck.Otolaryngologists are now paying more attention to biological influences exercised by the suspension of the common carotid artery circulation, in particular.The author used the canulating type Electromagnetic flow meter to measure and recorded quantitatively the experiment dog's blood flow of the common carotid artery and vertebral artery respectively, and observed * quantitative change of arterial circulation following the occlusion of the jugular vein and common carotid artery.These are to dynamically clarify the effect to be brought about by vessels thus processed upon the cerebral circulation from the side of blood flow amount.The results were as follows:1) The range of the common carotid artery flow was 26_??_72 m.l./min with the average of 52 m.l./min in 16 dogs.2) In 7 dogs, the range of the vertebral artery flow was 6_??_36 m.l./min with the average of 21 m.1/min.3) So far as acute experimental cases concerned, either unilateral or bilateral occlusion of the external jugular veins did not cause any change in the common carotid raterial flow.4) The unilateral occlusion of the common carotid artery caused a rapid increase of about 50% on an average in arterial flow of the contralateral common carotid artery.5) The right vertebral artery had on an average 55% increase of blood flow by the occlusion of the ipsilateral common carotid artery, but little change of the flow by the occlusion of the contralateral common carotid artery.The left vertebral artery had an about 9% increased flow after the occlusion of either the ipsilateral or the contralateral common carotid artery.6) Summarizing the above results, in the case of unilateral occlusion of the carotid artery, the involved loss of blood flow is supposed to be compensated by 60_??_80% through the contralateral common carotid artery and vertebral arteries(the rate of the vertebral arterial flow is assumed to be 1/2 of that of the common carotid artery), and the overall loss of the blood-flow would be minimized.7) In the case of unilateral ligation of the common carotid artery, the compensatory capacity of increase of blood flow, quantitatively speaking, is greater in the contralateral common carotid artery than in the vertebral arteries.From this fact we can infer that in regard to the function of peripheral collateral circulations, the right and left lateral circulation is better than the anteriorposterior collateral circulation.8) The elevation of systemic blood pressure caused by the ligation of the common carotid artery has only a secondary significance in the compensatory mechanism of increasing blood-flow at the carotid arterial system.