Tidal breathing patterns derived from structured light plethysmography in COPD patients compared with healthy subjects

Abstract

PurposeDifferences in tidal breathing patterns have been reported between patients with chronic obstructive pulmonary disease (COPD) and healthy individuals using traditional measurement techniques. This feasibility study examined whether structured light plethysmography (SLP) – a noncontact, light-based technique – could also detect differences in tidal breathing patterns between patients with COPD and healthy subjects.Patients and methodsA 5 min period of tidal (quiet) breathing was recorded in each patient with COPD (n=31) and each healthy subject (n=31), matched for age, body mass index, and sex. For every participant, the median and interquartile range (IQR; denoting within-subject variability) of 12 tidal breathing parameters were calculated. Individual data were then combined by cohort and summarized by its median and IQR.ResultsAfter correction for multiple comparisons, inspiratory time (median tI) and its variability (IQR of tI) were lower in patients with COPD (p<0.001 and p<0.01, respectively) as were ratios derived from tI (tI/tE and tI/tTot, both p<0.01) and their variability (p<0.01 and p<0.05, respectively). IE50SLP (the ratio of inspiratory to expiratory flow at 50% tidal volume calculated from the SLP signal) was higher (p<0.001) in COPD while SLP-derived time to reach peak tidal expiratory flow over expiratory time (median tPTEFSLP/tE) was shorter (p<0.01) and considerably less variable (p<0.001). Thoraco–abdominal asynchrony was increased (p<0.05) in COPD.ConclusionThese early observations suggest that, like traditional techniques, SLP is able to detect different breathing patterns in COPD patients compared with subjects with no respiratory disease. This provides support for further investigation into the potential uses of SLP in assessing clinical conditions and interventions.

Tidal breathing parameters measured using structured light plethysmography in healthy children and those with asthma before and after bronchodilator

“…mIE50 SLP has also been reported to be higher in patients with chronic obstructive pulmonary disease compared with healthy subjects (Motamedi‐Fakhr et al. ).…”

Tidal breathing parameters measured by structured light plethysmography in children aged 2-12 years recovering from acute asthma/wheeze compared with healthy children

“…) and adults with COPD (Motamedi‐Fakhr et al. ). IE50 SLP did not respond to the additional bronchodilator treatment administered to children with acute asthma/wheeze during this study and remained higher than normal despite the children being in the recovery phase of their illness and considered clinically stable.…”

Evaluation of the agreement of tidal breathing parameters measured simultaneously using pneumotachography and structured light plethysmography

“… IE 50 SLP is the ratio of TIF 50 SLP to TEF 50 SLP calculated from the displacement of the TA wall and its first derivative. Modified from Motamedi‐Fakhr et al . IE50, inspiratory to expiratory flow at 50% tidal volume; SLP , structured light plethysmography; TA , thoraco–abdominal; TEF50, tidal expiratory flow at 50% volume; TIF 50, tidal inspiratory flow at 50% volume.…”

“…,b; Motamedi‐Fakhr et al. ). To further test the robustness of the agreement between PNT‐ and SLP‐measured parameters, a separate cohort of healthy participants was recruited to examine the test–retest repeatability and the effect of a change in respiratory pattern and/or rate on the agreement between the devices.…”

“…; Motamedi‐Fakhr et al. ). SLP has also been used to monitor tidal breathing parameters during the recovery of patients who have undergone a lung resection operation (Elshafie et al.…”