Respiratory motion measured by respiratory inductance plethysmography often deviates from the sinusoidal pattern assumed in the traditional Lissajous figure (loop) analysis used to determine thoraco-abdominal asynchrony, or phase angle φ. We investigated six different time-domain methods of measuring φ, using simulated data with sinusoidal and triangular waveforms, phase shifts of 0-135°, and 10% noise. The techniques were then used on data from 11 lightly anesthetized rhesus monkeys (Macaca mulatta; 7.6 ± 0.8 kg; 5.7 ± 0.5 years old), instrumented with a respiratory inductive plethysmograph, and subjected to increasing levels of inspiratory resistive loading ranging from 5-1,000 cmH2O · L-1 · sec-1. The best results were obtained from cross-correlation and maximum linear correlation, with errors less than ∼5° from the actual phase angle in the simulated data. The worst performance was produced by the loop analysis, which in some cases was in error by more than 30°. Compared to correlation, other analysis techniques performed at an intermediate level. Maximum linear correlation and cross-correlation produced similar results on the data collected from monkeys (SD of the difference, 4.1°) but all other techniques had a high SD of the difference compared to the correlation techniques. We conclude that phase angles are best measured using cross-correlation or maximum linear correlation, techniques that are independent of waveform shape, and robust in the presence of noise. © 2002 Wiley-Liss, Inc.
CITATION STYLE
Prisk, G. K., Hammer, J., & Newth, C. J. L. (2002). Techniques for measurement of thoracoabdominal asynchrony. Pediatric Pulmonology, 34(6), 462–472. https://doi.org/10.1002/ppul.10204
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