PERIPHERAL VASCULAR DISEASES 



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and dilate, and thus the skin becomes bright red in 

 colour although the blood-flow through it may be 

 small." 



Some generalizations might be made from these 

 correlations. If the temperature of a part is warm, 

 there is a large volume flow; if it is cool, the volume 

 flow is small. If the depth of skin color is pale, the 

 cross-sectional area of the minute vessels is decreased; 

 whereas if a deep color is present, the cross-sectional 

 area is increased (vessels open). If the color is pink, 

 the velocity of blood flow is fast and oxygen satura- 

 tion high; if red, the velocity of flow is intermediate 

 and the oxygen saturation is intermediate; if blue, the 

 blood flow velocity is slow and the oxygen saturation 

 low. 



A crude estimation of the cutaneous circulatory 

 status may be obtained from the subpapillary venous 

 plexus filling time. Digital pressure on the skin for 

 several seconds results in displacement of blood into 

 adjacent and deeper lying areas. On sudden release 

 of this pressure, the normal skin shows a change 

 from the pallor to a normal color within i or i sec. 



Gravitational effects on the cutaneous circulation 

 may be employed in diagnosis and estimation of the 

 state of the circulation by means of elevation and 

 dependency tests. Here, the patient lies on his back 

 with the legs flexed to go degrees at the hip. He holds 

 this position for a certain length of time, usually i 

 min. If he will tolerate it, the patient may be requested 

 to flex and extend the ankle during this period. With 

 impairment of the circulation, the skin assumes a 

 white, waxy color during this maneuver. The patient 

 is then instructed to sit on the edge of the examining 

 table with his legs hanging dependent. Normally, 

 gravity and reactive hyperemia cause a return of 

 flushed color to the skin within a short interval of 

 time, usually 1 5 sec. A delay in return of color is 

 roughly proportional to the degree of circulatory 

 insufficiency. 



The test of venous filling may be performed simul- 

 taneously with the above gravitational test. The dura- 

 tion of time from the moment the patient sits until 

 the superficial veins of the legs are filled is a gross 

 indication of the circulatory status in the legs. 



