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“Effect of Pressure Exposure Area and Magnitude on Muscle Microvascular Blood Flow, Peripheral Tissue Volume and Central Volume”
Author(s) -
Bird Elizabeth,
Petersen Lonnie,
Hargens Alan
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.710.6
Subject(s) - blood flow , plethysmograph , photoplethysmogram , medicine , blood volume , blood pressure , peripheral , volume (thermodynamics) , cardiology , anatomy , anesthesia , physics , filter (signal processing) , quantum mechanics , computer science , computer vision
External pressure chambers can affect local blood flow, central blood flow, and the distribution of venous volume. Small chambers generating positive pressures are used for wound healing, while large chambers applying negative pressures are being investigated to reduce vision problems in astronauts. The purpose of this study is to determine the differences in systemic versus local effects generated by different‐sized chambers at different external pressures, specifically looking at the venous blood shifts, cardiac response, and local microvascular blood flow changes. Our hypotheses are: (1) larger pressure chambers will lead to more systemic effects such as venous and central blood redistributions, while smaller chambers will impact local microvascular flow more, and (2) the magnitude of effects seen in each chamber will depend on the magnitude of applied pressure. We measured the effect of 2 different pressure chamber sizes (unilateral leg and unilateral ankle) and 4 external pressure magnitudes (−40, −20, 20 and 40 mmHg) on skin and muscle microvascular flows (measured with photoplethysmography, PPG), lower leg circumference (measured with strain‐gauge plethysmography, SGP), and heart rate, blood pressure, and stroke volume (measured with Nexfen finger sphygmonometer). Five subjects were tested (3 female and 2 male, with average age, weight and height of 23 years, 65 kg, and 167 cm). A 2 way repeated measures ANOVA documented a significant effect of pressure magnitude on skin and muscle microvascular flow compared to ambient pressure, but no effect of chamber size and no interaction. The maximum increase in microvascular blood flow was 110 ± 70 % (p > 0.05) in muscle and 30.5 ± 40.24 % (p> 0.05) in skin, with both occurring at 20 mmHg in the leg chamber. The largest decrease in microvascular flow was 67.4 ± 7.5 % (p = 0.051) in the muscle and 76.7 ± 7.5 % (p = 0.014) in the skin, with both occurring at −40 mmHg in the ankle chamber. The power of pairwise comparisons between blood flows at different applied pressures was 0.30, suggesting that the number of subjects limits the detection of significant changes. Calf circumference and cardiovascular parameters were not affected by area or magnitude of pressure application. Smaller chambers had no effect on lower limb venous blood or central blood shifts. Support or Funding Information Supported by NASA grant NNX13AJ12G.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .