Blood Flow in Vascular Disorders

Leif Hillestad Abstract. The peripheral cutaneous vessels have been studied at various ambient temperatures and at local temperatures ranging from 40 to 6°C. At the higher local temperatures sympathetic stimuli exerted a strong effect upon the blood flow. By applying local cooling of increasing strength the influence of sympathetic stimuli upon the vascular tone was successively abolished. From around 15°C of local temperature and down to zero vessels were unresponsive to sympathetic nerve influence. It appears that the local cold stimulus is the major determinant of the vascular tone of the skin when man is exposed to cold. Studies of the cutaneous circulation under the same conditions were carried out in patients suffering from various peripheral vascular disorders. Local cold was again found to be the determinant factor for producing the abnormal vasoconstriction. Abolition of sympathetic tone did not prevent the occurrence of spasmodic attacks. The hemodynamic difference between cold‐sensitivity in vasospastic and in obstructive arterial disease of the hands is demonstrated. The findings are discussed in the light of presently applied criteria for treatment of cold‐sensitive peripheral vascular disorders.