Skin Blood Pressure in Hypertensive Subjects Measured by Photoelectric Technique

Abstract

Using a photoelectric probe placed under a cuff, skin blood pressure was measured at the arm in 104 normotensive subjects and in 62 hypertensive subjects aged 20–60 years simultaneously with auscultatory measurement of arm blood pressure. The cuff was inflated to suprasystolic pressure level so that skin ischaemia was present, as evidenced by blanching. On gradual cuff release skin blood pressure was defined as the external counter pressure at which the skin began to redden, probably due to filling of capillaries and venules. A significant correlation was found between skin blood pressure and systolic respectively diastolic arm blood pressure. The skin blood pressure was found significantly higher in the hypertensive subjects than in normals (118 mm Hg, S.D. 21 compared to 86 mm Hg, S.D. 13, p < 0.01). These findings suggest that a high central blood pressure is transmitted far out in the arterial vascular system. Increasing central blood pressure gives an increasing gradient between central and peripheral blood pressure in hypertensive subjects as measured by the present method. Drug-induced decrease of central blood pressure by methyl-dopa and beta-blocking agents is followed by a concomitant decrease of skin blood pressure independent of the drug used.

Key Words:

• Arteriolar blood pressure
• hypertension
• indirect blood pressure measurement
• photoelectric plethysmography
• skin blood pressure