Impact of wall filter selection on the detection of vasomotor changes in the brachial artery: a pilot study.
During Doppler ultrasound assessment of blood flow, a wall filter is used to reduce or eliminate high-amplitude, low-velocity signals from the vessel wall and the surrounding tissue. This study investigated the impact of a range of wall filters (22 Hz, 75 Hz, 128 Hz, and 252 Hz) on the accuracy of forearm blood flow monitoring during the sympathoexcitatory application of lower body negative pressure, when peripheral blood flow may decrease substantially. The 252 Hz filter eliminated diastolic flow in 4 of 10 participants. In the remaining participants, the 252 Hz filter minimized the sensitivity of the pulsatility index. The interpretation of physiological responses could ultimately be compromised by using filters beyond 128 Hz.
Neurovascular Research Laboratory, University of Western Ontario, London, ON N6A3K7, Canada. michelj@nipissingu.ca
Michel J
MJ
Johnson
J Kevin
JK
Shoemaker
D000293:Adolescent; D000328:Adult; D001783:Blood Flow Velocity; D001794:Blood Pressure; D001916:Brachial Artery / Q000000981:diagnostic imaging* / Q000294:innervation; D004867:Equipment Design; D005260:Female; D005542:Forearm / Q000098:blood supply*; D006801:Humans; D008150:Lower Body Negative Pressure; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011237:Predictive Value of Tests; D011673:Pulsatile Flow; D012039:Regional Blood Flow; D018617:Ultrasonography, Doppler, Pulsed / Q000295:instrumentation*; D014655:Vascular Resistance; D014666:Vasomotor System / Q000502:physiology; D055815:Young Adult