Abstract
Breathing loops can be obtained by plotting two respiratory signals on an x-y diagram: the resulting loops represent a non-parametric, description of the respiratory system. In infancy, loops are commonly measured during tidal breathing and their interpretation is hampered by high within-subject variability. Therefore a two-dimensional averaging technique for loops has been developed. The algorithm is based on segmentation of the loops and required two steps. First, the total length of the loop of every breathing cycle was divided into a specified number of equidistant intervals and the co-ordinates calculated by stepwise linear approximation of the curve. Second, averaged loops were calculated using the arithmetical mean (or the median if there were artifacts) of the x and y co-ordinates of the loops for all calculated points. To compare the new technique with averaging in the time domain a simulation study was performed using respiratory signals with a coefficient of variation (CV) of 5%, 10%, 15% and 20%. In contrast to the new technique, with increasing CV, averaging in the time domain led to increasing contortions in the averaged flow-volume loops. Mean errors of peak tidal expiratory flow were −3.3%, −13.9%, −21.3% and −34.2%, whereas errors with the new technique were considerably lower (0.5%, 0.4%, 0.5% and −0.1%) and independent of the level of CV.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Ahlstrom, H., andJonson, B. (1974): ‘Pulmonary mechanics in infants. Methodological aspects’,Scand. J. Respir. Dis.,55, pp. 129–140
Benchetrit, G., Shea, S. A., Dinh, T. P., Bodocco, S., Baconnier, P., andGuz, A. (1989): ‘Individuality of breathing patterns in adults assessed over time’,Respir. Physiol. 75, pp. 199–209
Foitzik, B., Schmidt, M., Proquitte, H., andSchmalisch G. (1998): ‘Interactive computer program for separating respiratory pressure in newborn infants into its elastic, viscous and inert components’,Biomed. Tech.,43, pp. 278–279
Gnanaratnem, J., andFiner, N. N. (2000): ‘Neonatal acute respiratory failure’,Curr. Opin. Pediatr.,12, pp. 227–232
Greenough, A. (2000): ‘Measuring respiratory outcome’,Semin. Neonatol. 5, pp. 119–126
Hershenson, M. B., Colin, A. A., Wohl, M. E., andStark, A. R. (1990): ‘Changes in the contribution of the rib cage to tidal breathing during infancy’,Am. Rev. Respir. Dis.,141, pp. 922–925
Khoo, M. C. (2000): ‘Determinants of ventilatory instability and variability’,Respir. Physiol.,122, pp. 167–182
Lanteri, C. J., Petak, F., Gurrin, L., andSly, P. D. (1999): ‘Influence of inertance on respiratory mechanics measurements in mechanically ventilated puppies’,Pediatr. Pulmonol.,28, pp. 130–138
Lodrup-Carlsen, K. C. (1997): ‘Tidal breathing analysis in infants and preschool children: tidal flow-volume loops’ inZach, M., Carlsen, K. H., Warner, J. O., andSennhauser, F. H. (Eds): ‘New diagnostic techniques in paediatric respiratory medicine’ (ERS Monograph 5, ERS Journals, Sheffield), pp. 27–57
Paetow, U., Windstetter, D., andSchmalisch, G. (1999): ‘Variability of tidal breathing flow-volume loops in healthy and sick newborns’,Am. J. Perinatol.,16, pp. 549–559
Sammon, M. (1994): ‘Symmetry, bifurcations, and chaos in a distributed respiratory control system’,J. Appl. Physiol.,77, pp. 2481–2495
Sammon, M., Romaniuk, J. R., andBruce, E. N. (1993): ‘Bifurcations of the respiratory pattern associated with reduced lung volume in the rat’,J. Appl. Physiol. 75, pp. 887–901
Sato, J., andRobbins, P. A. (2001): ‘Methods for averaging irregular respiratory flow profiles in awake humans’,J. Appl. Physiol. 90, pp. 705–712
Schmalisch, G., Foitzik, B., Wauer, R. R., andStocks, J. (2001): ‘Effect of apparatus dead space on breathing parameters in newborns: “flow-through” versus conventional techniques’,Eur. Respir. J.,17, pp. 108–114
Small, M., Judd, K., Lowe, M., andStick, S. (1999): ‘Is breathing in infants chaotic? Dimension estimates for respiratory patterns during quiet sleep’,J. Appl. Physiol.,86, pp. 359–376
Stocks, J., Dezateux, C. A., Jackson, E. A., Hoo, A. F., Costeloe, K. L., andWade, A. M. (1994): ‘Analysis of tidal breathing parameters in infancy: how variable in tPTEF/tE’,Am. J. Respir. Crit. Care Med.,150, pp. 1347–1354
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Schmalisch, G., Schmidt, M. & Foitzik, B. Novel technique to average breathing loops for infant respiratory function testing. Med. Biol. Eng. Comput. 39, 688–693 (2001). https://doi.org/10.1007/BF02345443
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02345443