Summary We measured carotid and brachial artery blood flow by Doppler ultrasound in 11 human volunteers, and related these to cardiac index and to each other. The median (IQR [range]) carotid arterial blood flow was 0.334 (0.223-0.381 [0.052-0.563]) l.min-1 on the right and 0.315 (0.223-0.369 [0.061-0.690]) l.min-1 on the left. The brachial arterial blood flow was 0.049 (0.033-0.062 [0.015-0.204]) l.min-1 on the right and 0.039 (0.027-0.054 [0.011-0.116]) on the left. Cardiac index was 3.2 (2.8-3.5 [1.9-5.4]) l.min-1.m-2. There was a moderate to good correlation between right-and left-sided flows (brachial: ? = 0.45; carotid: ? = 0.567). Brachial and carotid flow had no or a negative correlation with cardiac index (right brachial: ? = -0.145, left brachial: ? = -0.349; right carotid: ? = -0.376, left carotid: ? = -0.285). In contrast to some previous studies, we found that Doppler-estimated peripheral arterial blood flows only show a weak correlation with cardiac index and cannot be used to provide non-invasive estimates of cardiac index in man.
- Adult Blood Flow Velocity/physiology Brachial Artery/diagnostic imaging/*physiology Cardiac Output/*physiology Carotid Artery, Common/diagnostic imaging/*physiology Female Humans Male Middle Aged Pilot Projects Prospective Studies Regional Blood Flow/physiology Reproducibility of Results Ultrasonography, Doppler/methods