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In vivo assessment of blood pooling and muscle pump dynamics under orthostatic stress
Author(s) -
Leguy Carole,
Blaber Andrew,
Kuemmel Jakob,
Beck Luis,
Zange Jochen,
Rittweger Joern
Publication year - 2013
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.27.1_supplement.903.4
Subject(s) - medicine , blood pressure , orthostatic vital signs , femoral artery , orthostatic intolerance , cardiology , blood flow , anatomy
A better understanding of blood pooling to the lower limbs and muscle pumping (increasing venous return) is essential to prevent orthostatic intolerance. The goal of this study is to assess the dynamics of these physiological responses under orthostatic stress. Repeated 70 degrees Head Up Tilt (HUT) of 3 minutes were performed on a group of 15 healthy volunteers. After 1st and 2nd minute of HUT, the subjects performed a 3 s calf Muscle Contraction (MC) at 30% of maximal electromyographic activity. Calf muscles EMG, ECG and finger blood pressure were recorded continuously. Blood volume flow (BVF) of the femoral artery was assessed with ultrasound from 1 min before to 1 min after HUT. A peak BVF of 620 mL/min was measured after HUT, whereas peak BVF after MC reached 950 mL/min. Plateau BVF in the femoral artery during HUT increased slightly after the MC possibly due to a metabolic response of the leg muscle. Finally, mean arterial pressure immediately after tilting and after MC decreased. We therefore conclude that the muscle pump through its effect on venous pressure of the lower limbs is a fundamental aspect in blood pressure regulation during orthostatic stress.