Altered respiratory tissue mechanics in asymptomatic wheezy infants

Graham L. Hall, Zoltán Hantos, Peter D. Sly

Research output: Contribution to journalArticle

20 Citations (Scopus)


Low-frequency forced oscillation (LFOT) and raised volume rapid thoracic compression (RVRTC) techniques were used to measure airways and respiratory tissue mechanics and forced expiratory volumes in 24 asymptomatic infants with recurrent wheeze. Total respiratory impedance spectra (Zrs) (0.5 to 20 Hz) were obtained (n = 22) and a model containing airway (resistance [Raw] and inertance [law]) and constant-phase tissue (tissue damping [G] and tissue elastance [H]) compartments fitted to Zrs. Forced expiratory volumes (FEV0.5)were determined (n = 16). Standardized variants (Z scores) were calculated for comparison to a healthy population (Hall et al., Am J Respir Crit Care Med 2000;162:1397-1402). Wheezy infants had elevated H (Z scores: 0.61 ± 0.20; p = 0.007) but not Raw (0.14 ± 0.25; p > 0.2), G (0.41 ± 0.21; p = 0.066), or FEV0.5 (-0.25 ± 0.25; p > 0.2) compared with healthy infants. Infants younger than 1 yr of age were not significantly different from normals, whereas lung function from infants older than 1 yr had deviated from normal infants, with Z scores of 0.58 ± 0.2 (p = 0.018), 0.79 ± 0.31 (p = 0.032), 1.06 ± 0.25 (p = 0.002), and -0.94 ± 0.22 (p = 0.007) for Raw, G, H, and FEV0.5 respectively. We conclude that asymptomatic infants with recurrent wheeze have altered lung function. The abnormalities were more pronounced in respiratory tissue mechanics than in airway mechanics or forced volumes, highlighting the value of techniques capable of partitioning lung function into airway and respiratory tissue components.

Original languageEnglish
Pages (from-to)1387-1391
Number of pages5
JournalAmerican Journal of Respiratory and Critical Care Medicine
Issue number8 I
Publication statusPublished - Oct 15 2001


  • Airway and respiratory tissue mechanics
  • Forced expiratory volumes
  • Low-frequency forced oscillations
  • Wheezy infants

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine

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