SLP detects tidal breathing patterns like traditional measurement techniques


Structured light plethysmography (SLP), a noncontact, light-based technique, can detect different breathing patterns similar to traditional techniques in patients with chronic obstructive pulmonary disease (COPD) compared with those without any respiratory disease, a study has found.

There have been reported differences in tidal (quiet) breathing patterns between patients with COPD and healthy individuals using traditional measurement techniques, according to researchers who examined whether SLP could also detect differences in tidal breathing patterns between healthy individuals and COPD patients.

The authors recorded a 5-min period of tidal breathing in each COPD patients (n=31) and each healthy participant (n=31), matched for age, body mass index and sex. They calculated the median and interquartile (IQR; denoting within-subject variability) of 12 tidal breathing parameters for every participant, combined individual data by cohort, and summarized these by its median and IQR.

COPD patients had lower inspiratory time (median tI) and variability (IQR of tI) after correction for multiple comparisons (p<0.001 and p<0.01, respectively), as well as ratios derived from tI (tI/tE and tI/tTot; both p<0.01) and their variability (p<0.01 and p<0.05, respectively).

The COPD group also had higher (p<0.001) IE50SLP (the ratio of inspiratory to expiratory flow at 50 percent tidal volume calculated from the SLP signal), but shorter (p<0.01) and considerably less variable (p<0.001) SLP-derived time to reach peak tidal expiratory flow over expiratory time (median tPTEFSLP/tE). Additionally, thoraco-abdominal asynchrony was elevated (p<0.05) in COPD.

The finding provides support for “further investigation into the potential uses of SLP in assessing clinical conditions and interventions,” according to researchers.