Re. Beadle et al., CHARACTERIZATION OF A DENSITY-CORRECTED ULTRASONIC PNEUMOTACHOMETER FOR HORSES, Journal of applied physiology, 78(1), 1995, pp. 359-367
A density-corrected ultrasonic pneumotachometer designed specifically
for horses (UF202) was evaluated and characterized with the aid of a c
ustom-built apparatus. UF202 provided voltage outputs for airflow thro
ugh and gas density within the flowhead. Baseline stability for flow c
hannel output (V-UF202) was <0.35% full scale (FS), and V-UF202 was li
near over a range of +/-50 l/s (R(2) greater than or equal to 0.9976).
Under optimal conditions, V-UF202 accuracy was determined to be +/-1.
00% FS and repeatability was +/-0.78% FS. V-UF202 resolution was 24 ml
/s. The rise time for V-UF202 was 18 ms, and the -3-dB point was 18 Hz
; digital compensation provided a flat frequency response to 32 Hz. V-
UF202 gain appeared to be stable over a period of 8 days. Density chan
nel output (rho(UF202)) was linear over a range of 1.11-1.23 g/l (R(2)
greater than or equal to 0.9645). rho(UF202) accuracy was calculated
to be +/-0.50% FS, and rho(UF202) repeatability was determined to be /-0.30% FS. Resistance of the flowhead was determined to be 0.013 cmH(
2)O.l(-1).s at a flow of 40 l/s. On the basis of this study, we conclu
de that UF202 should facilitate accurate measurement of breath-by-brea
th airflow of exercising horses.