title: Evaluation of the agreement of tidal breathing parameters measured simultaneously using pneumotachography and structured light plethysmography.
abstract: Structured light plethysmography (SLP) is a noncontact, noninvasive, respiratory measurement technique, which uses a structured pattern of light and two cameras to track displacement of the thoraco-abdominal wall during tidal breathing. The primary objective of this study was to examine agreement between tidal breathing parameters measured simultaneously for 45 sec using pneumotachography and SLP in a group of 20 participants with a range of respiratory patterns ("primary cohort"). To examine repeatability of the agreement, an additional 21 healthy subjects ("repeatability cohort") were measured twice during resting breathing and once during increased respiratory rate (RR). Breath-by-breath and averaged RR, inspiratory time (tI), expiratory time (tE), total breath time (tTot), tI/tE, tI/tTot, and IE50 (inspiratory to expiratory flow measured at 50% of tidal volume) were calculated. Bland-Altman plots were used to assess the agreement. In the primary cohort, breath-by-breath agreement for RR was ±1.44 breaths per minute (brpm). tI, tE, and tTot agreed to ±0.22, ±0.29, and ±0.32 sec, respectively, and tI/tE, tI/tTot, and IE50/IE50SLPto ±0.16, ±0.05, and ±0.55, respectively. When averaged, agreement for RR was ±0.19 brpm. tI, tE, and tTot were within ±0.16, ±0.16, and ±0.07 sec, respectively, and tI/tE, tI/tTot, and IE50 were within ±0.09, ±0.03, and ±0.25, respectively. A comparison of resting breathing demonstrated that breath-by-breath and averaged agreements for all seven parameters were repeatable (P> 0.05). With increased RR, agreement improved for tI, tE, and tTot (P≤ 0.01), did not differ for tI/tE, tI/tTot, and IE50 (P> 0.05) and reduced for breath-by-breath (P< 0.05) but not averaged RR (P> 0.05).
authors.affiliation: PneumaCare Ltd., Ely, UK shayan.motamedi@pneumacare.com.
authors.forename: Shayan
authors.initials: S
authors.lastname: Motamedi-Fakhr
authors.affiliation: Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Iles
authors.affiliation: ISVR, Faculty of Engineering and Environment, University of Southampton, Southampton, UK.
authors.forename: Anna
authors.initials: A
authors.lastname: Barney
authors.affiliation: PneumaCare Ltd., Ely, UK.
authors.forename: Willem
authors.initials: W
authors.lastname: de Boer
authors.affiliation: Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
authors.forename: Jenny
authors.initials: J
authors.lastname: Conlon
authors.affiliation: PneumaCare Ltd., Ely, UK.
authors.forename: Amna
authors.initials: A
authors.lastname: Khalid
authors.affiliation: PneumaCare Ltd., Ely, UK.
authors.forename: Rachel C
authors.initials: RC
authors.lastname: Wilson
mesh_terms: D000328:Adult; D000368:Aged; D002648:Child; D003948:Diagnostic Techniques, Respiratory System; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D010991:Plethysmography / Q000379:methods*; D015203:Reproducibility of Results; D012119:Respiration; D015656:Respiratory Mechanics; D056152:Respiratory Rate; D013990:Tidal Volume
keywords: Bland–Altman; IE50; pneumotachography; structured light plethysmography; tidal breathing; validation