THE CONTRIBUTIONS OF ARTERIAL AND VENOUS VOLUMES TO INCREASED CUTANEOUS BLOOD-FLOW DURING LEG COMPRESSION

Intermittent lower extremity compression increases cutaneous blood flo w. The source of this increased perfusion and, the influence of physic al activity on stimulated foot skin perfusion has not been elucidated. The purpose of this study is to determine the arterial and venous con tributions to augmented cutaneous blood flow during foot and leg compr ession, and to evaluate whether physical activity influenced the respo nse to compression. Fifty limbs from 29 normal volunteers were studied in the sitting position. Their daily physical activity was categorize d as active if they exercised greater than or equal to 3 days/week or sedentary if they exercised less than or equal to 3 days/week. Inflata ble foot and calf compression cuffs attached to a timed-pressure pump (Art-assist AA 1000, ACI, Inc., San Marcos, CA) were applied to the su bject's leg and set to deliver 120 mmHg pressure with a 10-sec deflati on cycle. Skin perfusion of the great toe was recorded by a laser Dopp ler (Laserflo Model BPM 403, TSI, Inc., St. Paul, MN). Total perfusion with compression (A), retrograde venous perfusion (B), and compressio n artifact (C) was recorded. Mean values for A, B, and C and the diffe rences between the two groups were analyzed using multivariate multipl e comparison statistical method. The mean baseline skin perfusion was 3.96 +/- 0.91, and mean total stimulated skin perfusion (A) was 9.23 /- 2.13. With arterial inflow obliterated and compression applied, mea n skin perfusion (B) was 1.96 +/- 0.44. The sedentary group had a mean resting perfusion of 1.64 +/- 0.28 and mean stimulated value (A) of 2 .29 +/- 0.37 ml/min/100 gm tissue. The active group had a mean resting perfusion of 28.26 +/- 0.91, and stimulated value (A) of 32.65 +/- 4. 47 ml/min/100 gm tissue. These differences in the mean skin perfusion between the two groups were significant. It is concluded that in norma ls, the majority of increased perfusion is from increased arterial inf low. There is a larger resting foot skin perfusion in active individua ls and they have quantitatively greater stimulated inflow compared to sedentary individuals.