Noninvasive, quantitative determination of muscle blood flow in man by a combination of venous-occlusion plethysmography and computed tomography

1988 ◽  
Vol 83 (3) ◽  
pp. 327-341 ◽  
Author(s):  
F. Weber ◽  
M. Anlauf ◽  
M. Serdarevic
Keyword(s):  
Computed Tomography ◽  
Blood Flow ◽  
Quantitative Determination ◽  
Muscle Blood Flow ◽  
Venous Occlusion ◽  
Venous Occlusion Plethysmography

Blood flow distribution in working in situ canine muscle during blood flow reduction

1996 ◽  
Vol 80 (6) ◽  
pp. 1978-1983 ◽  
Author(s):  
S. S. Kurdak ◽  
B. Grassi ◽  
P. D. Wagner ◽  
M. C. Hogan
Keyword(s):  
Blood Flow ◽  
Muscle Blood Flow ◽  
Flow Distribution ◽  
Blood Flow Distribution ◽  
Strong Negative Correlation ◽  
Flow Heterogeneity ◽  
Blood Flow Reduction ◽  
Blood Flow Heterogeneity

The purpose of this study was to determine whether reduction in apparent muscle O2 diffusing capacity (Dmo2) calculated during reduced blood flow conditions in maximally working muscle is a reflection of alterations in blood flow distribution. Isolated dog gastrocnemius muscle (n = 6) was stimulated for 3 min to achieve peak O2 uptake (VO2) at two levels of blood flow (controlled by pump perfusion): control (C) conditions at normal perfusion pressure (blood flow = 111 +/- 10 ml.100 g-1.min-1) and reduced blood flow treatment [ischemia (I); 52 +/- 6 ml.100 g-1.min-1]. In addition, maximal vasodilation was achieved by adenosine (A) infusion (10(-2)M) at both levels of blood flow, so that each muscle was subjected randomly to a total of four conditions (C, CA, I, and IA; each separated by 45 min of rest). Muscle blood flow distribution was measured with 15-microns-diameter colored microspheres. A numerical integration technique was used to calculate Dmo2 for each treatment with use of a model that calculates O2 loss along a capillary on the basis of Fick's law of diffusion. Peak VO2 was reduced significantly (P < 0.01) with ischemia and was unchanged by adenosine infusion at either flow rate (10.6 +/- 0.9, 9.7 +/- 1.0, 6.7 +/- 0.2, and 5.9 +/- 0.8 ml.100 g-1.min-1 for C, CA, I, and IA, respectively). Dmo2 was significantly lower by 30-35% (P < 0.01) when flow was reduced (except for CA vs. I; 0.23 +/- 0.03, 0.20 +/- 0.02, 0.16 +/- 0.01, and 0.13 +/- 0.01 ml.100 g-1.min-1.Torr-1 for C, CA, I, and IA, respectively). As expressed by the coefficient of variation (0.45 +/- 0.04, 0.47 +/- 0.04, 0.55 +/- 0.03, and 0.53 +/- 0.04 for C, CA, I, and IA, respectively), blood flow heterogeneity per se was not significantly different among the four conditions when examined by analysis of variance. However, there was a strong negative correlation (r = 0.89, P < 0.05) between Dmo2 and blood flow heterogeneity among the four conditions, suggesting that blood flow redistribution (likely a result of a decrease in the number of perfused capillaries) becomes an increasingly important factor in the determination of Dmo2 as blood flow is diminished.

Peripheral blood flow during rewarming from mild hypothermia in humans

1985 ◽  
Vol 58 (1) ◽  
pp. 4-13 ◽  
Author(s):  
G. K. Savard ◽  
K. E. Cooper ◽  
W. L. Veale ◽  
T. J. Malkinson
Keyword(s):  
Blood Flow ◽  
Core Temperature ◽  
Skin Blood Flow ◽  
Cold Water ◽  
Mild Hypothermia ◽  
Muscle Blood Flow ◽  
Venous Occlusion ◽  
Warm Bath ◽  
Peripheral Blood Flow ◽  
Deep Body Temperature

During the initial stages of rewarming from hypothermia, there is a continued cooling of the core, or after-drop in temperature, that has been attributed to the return of cold blood due to peripheral vasodilatation, thus causing a further decrease of deep body temperature. To examine this possibility more carefully, subjects were immersed in cold water (17 degrees C), and then rewarmed from a mildly hypothermic state in a warm bath (40 degrees C). Measurements of hand blood flow were made by calorimetry and of forearm, calf, and foot blood flows by straingauge venous occlusion plethysmography at rest (Ta = 22 degrees C) and during rewarming. There was a small increase in skin blood flow during the falling phase of core temperature upon rewarming in the warm bath, but none in foot blood flow upon rewarming at room air, suggesting that skin blood flow seems to contribute to the after-drop, but only minimally. Limb blood flow changes during this phase suggest that a small muscle blood flow could also have contributed to the after-drop. It was concluded that the after-drop of core temperature during rewarming from mild hypothermia does not result from a large vasodilatation in the superficial parts of the periphery, as postulated. The possible contribution of mechanisms of heat conduction, heat convection, and cessation of shivering thermogenesis were discussed.

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