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

Shayan Motamedi-Fakhr, Rachel C Wilson, Richard Iles, Shayan Motamedi-Fakhr, Rachel C Wilson, Richard Iles

Abstract

Purpose: Differences 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 methods: A 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.

Results: After 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.

Conclusion: These 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.

Keywords: IE50; chronic obstructive pulmonary disease; structured light plethysmography; thoraco-abdominal asynchrony; tidal breathing.

Conflict of interest statement

This paper was presented at the European Respiratory Society International Congress 2015 as a poster presentation with interim findings. The poster’s abstract was published in European Respiratory Journal 2015 46: PA2283; DOI: 10.1183/13993003.congress-2015.PA2283. RI is a shareholder of and part-time paid medical advisor to PneumaCare Ltd. RW and SMF are employees of and have share options for PneumaCare Ltd. The authors report no other conflicts of interest in this work.

Figures

Figure 1
Figure 1
Working principle of SLP. Notes: A structured grid of light is projected onto the subject’s anterior TA wall (top-left). Displacements of this grid during tidal breathing are captured by two digital video cameras. This diagram shows the anterior TA wall split into two sections, one representing the thorax and the other the abdomen. Averaging the axial displacement of the surfaces corresponding to the thorax and abdomen, the thorax alone or the abdomen alone provides a means to generate one-dimensional time series corresponding to displacement of the full body, thorax, or abdomen, respectively (bottom). A 3D reconstruction of the TA wall surface is also generated during SLP (top-right). The grid top can also be divided into left and right hemithorax or any custom regions chosen for comparison. Abbreviations: SLP, structured light plethysmography; TA, thoraco–abdominal; 3D, three dimensional.
Figure 2
Figure 2
Illustration of how IE50SLP differed between a patient with COPD (right) and his or her age-, body mass index-, and sex-matched healthy subject (left). Notes: An SLP suffix added to the abbreviation emphasizes that the parameter is calculated from SLP signals. SLP does not measure absolute flow or volume but measures the displacement of the TA wall (analogous to volume) and the rate of TA displacement (analogous to flow). Abbreviations: COPD, chronic obstructive pulmonary disease; IE50SLP, SLP-derived tidal inspiratory flow at 50% of inspiratory volume divided by tidal expiratory flow at 50% of expiratory volume; SLP, structured light plethysmography; TA, thoraco–abdominal; TEF50SLP, SLP-derived tidal expiratory flow at 50% of expiratory volume; TIF50SLP, SLP-derived tidal inspiratory flow at 50% of inspiratory volume.

References

    1. Ghezzi M, Tenero L, Piazza M, Bodini A, Piacentini G. Structured light plethysmography: new method to evaluate expiratory flow limitation in asthmatic children. Eur Respir J. 2015;46(Suppl 59):PA3641.
    1. Hmeidi H, Chadwick E, Lenney W, et al. IE50 measured by structured light plethysmography (SLP) can differentiate between children with and without asthma, and can detect response to a bronchodilator. Am J Respir Crit Care Med. 2016;193 Meeting Abstracts:A4505.
    1. Hmeidi H, Chadwick E, Lenney W, et al. Structured light plethysmography (SLP) can quantify abnormal breathing in children aged 2–12 admitted with acute asthma. Am J Respir Crit Care Med. 2016 193 Meeting Abstracts:A4506.
    1. Elshafie G, Kumar P, Motamedi-Fakhr S, Iles R, Wilson RC, Naidu B. Measuring changes in chest wall motion after lung resection using structured light plethysmography: a feasibility study. Interact Cardiovasc Thorac Surg. 2016;23(4):544–547.
    1. Chen Y, Xin Z, Qin C. Analysis of tidal breathing flow-volume curves in stable COPD patients. Chinese J Prac Intern Med. 2005;11:978–980.
    1. Kostianev S, Hristova A, Iluchev D. Characteristics of tidal expiratory flow pattern in healthy people and patient with chronic obstructive pulmonary disease. Folia Med (Plovdiv) 1999;41(3):18–25.
    1. Morris MJ, Williams EM, Madgwick R, Banerjee R, Phillips E. Changes in lung function and tidal airflow patterns after increasing extrathoracic airway resistance. Respirology. 2004;9(4):474–480.
    1. Wilkens H, Weingard B, Lo Mauro A, et al. Breathing pattern and chest wall volumes during exercise in patients with cystic fibrosis, pulmonary fibrosis and COPD before and after lung transplantation. Thorax. 2010;65(9):808–814.
    1. Williams EM, Madgwick RG, Morris MJ. Tidal expired airflow patterns in adults with airway obstruction. Eur Respir J. 1998;12(5):1118–1123.
    1. Williams EM, Powell T, Eriksen M, Neill P, Colasanti R. A pilot study quantifying the shape of tidal breathing waveforms using centroids in health and COPD. J Clin Monit Comput. 2014;28(1):67–74.
    1. Stick S. Stocks J, Sly P, Tepper R, Morgan W. Infant Respiratory Function Testing. New York: Wiley-Liss Inc; 1996. Measurements during tidal breathing; pp. 117–138.
    1. Poole K, Thompson, Hallinan H, Beardsmore C. Respiratory inductance plethysmography in healthy infants: a comparison of three calibration methods. Eur Respir J. 2000;16(6):1084–1090.
    1. Parreira VF, Vieira DS, Myrrha MA, Pessoa IM, Lage SM, Britto RR. Optoelectronic plethysmography: a review of the literature. Braz J Phys Ther. 2012;16(6):439–453.
    1. de Boer W, Lasenby J, Cameron J, et al. In: Labrosse F, Zwiggelaar R, Liu Y, Tiddeman B, editors. SLP: a zero-contact non-invasive method for pulmonary function testing; Proceedings of the British Machine Vision Conference; Aberystwyth: BMVA Press; 2010. [Accessed July 15, 2016]. pp. 85.1–85.12. Availble from: .
    1. Bates JH, Schmalisch G, Filbrun D, Stocks J. Tidal breath analysis for infant pulmonary function testing. Eur Respir J. 2000;16(6):1180–1192.
    1. Schmidt M, Foitzik B, Wauer RR, Winkler F, Schmalisch G. Comparative investigations of algorithms for the detection of breaths in newborns with disturbed respiratory signals. Comput Biomed Res. 1998;31(6):413–425.
    1. Konno K, Mead J. Measurement of the separate volume changes of rib cage and abdomen during breathing. J Appl Physiol. 1967;22(3):407–422.
    1. Sivan Y, Allen JL. Measurements of chest wall function. In: Stocks J, Sly P, Tepper R, Morgan W, editors. Infant Respiratory Function Testing. New York: Wiley-Liss Inc; 1996. pp. 340–351.
    1. McGraw KO, Wong S. A common language effect size statistic. Psychol Bull. 1992;111(2):361.
    1. Benjamini Y, Hochberg Y. Controlling the false discovery rate: a practical and powerful approach to multiple testing. J R Stat Soc Series B Stat Methodol. 1995;57(1):289–300.
    1. Tauber E, Fazekas T, Eichler I, et al. Negative expiratory pressure: a new tool for evaluating lung function in children? Pediatr Pulmonol. 2003;35(3):162–168.
    1. Priori R, Aliverti A, Albuquerque AL, Quaranta M, Albert P, Calverley PM. The effect of posture on asynchronous chest wall movement in COPD. J Appl Physiol. 2013;114(8):1066–1075.
    1. Sackner MA, Gonzalez H, Rodriguez M, Belsito A, Sackner DR, Grenvik S. Assessment of asynchronous and paradoxic motion between rib cage and abdomen in normal subjects and in patients with chronic obstructive pulmonary disease. Am Rev Respir Dis. 1984;130(4):588–593.
    1. Chien JY, Ruan SY, Huang YC, Yu CJ, Yang PC. Asynchronous thoraco-abdominal motion contributes to decreased 6-minute walk test in patients with COPD. Respir Care. 2013;58(2):320–326.
    1. Stick SM, Ellis E, Lesouëf PN, Sly PD. Validation of respiratory inductance plethysmography (“Respitrace”®) for the measurement of tidal breathing parameters in newborns. Pediatr Pulmonol. 1992;14(3):187–191.
    1. Laveneziana P, Llontop C, Nierat M-C, Bellocq A, Straus C, Similowski T. Disruption of tidal breathing in COPD by use of pneumotachograph and mouthpiece compared to non-contact measurement with structured light plethysmography (SLP) Eur Respir J. 2015;46(Suppl 59):PA511.
    1. Iles R, Khalid A, Kimber K, Wilson R, De Boer W. Non invasive measurement of respiratory rate: comparison between the Embletta® (Gold) respiband device and Thora3Di, PneumaCare Ltd. Am J Respir Crit Care Med. 2014;189 Meeting Abstracts:A2935.
    1. Caretti DM, Pullen PV, Premo LA, Kuhlmann WD. Reliability of respiratory inductive plethysmography for measuring tidal volume during exercise. Am Ind Hyg Assoc J. 1994;55(10):918–923.
    1. Vogels R, Pedley M, Aliverti A, Iles R. Non-invasive assessment of lung function, with reference to external light-based techniques. European Respiratory Society; 2012. [Accessed December 10, 2015]. (ERS Buyers Guide). Available from: .
    1. Iles R, Motamedi-Fakhr S, De Boer W, Conlon J, Khalid A, Wilson RC. Comparison of tidal breathing indices measured simultaneously using pneumotachography and structured light plethysmography (SLP) Am J Respir Crit Care Med. 2015;191:A2111.

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