Airway resistance measurements throughout the respiratory cycle in infants

Caroline S. Beardsmore, Simon Godfrey, Netta Shani, Channi Maayan, Ephraim Bar-Yishay

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Using a constant-volume infant whole-body plethysmograph containing a heated rebreathing bag, we have been able to measure airway resistance (Raw) throughout the respiratory cycle using a computer-based technique. Data from the plethysmograph transducers are sampled at 60 Hz for the calculations and Raw is calculated at each point sampled during the breath, with appropriate corrections for absolute lung volume. It was found that in most cases Raw varied less with respect to tidal volume than to tidal flow. Various patterns of Raw change in relation to tidal volume were found. These included an elevated but relatively constant resistance, a progressively rising expiratory resistance, and in 3 infants with laryngomalacia, a progressively rising inspiratory resistance. It was also found that the dynamic performance of the rebreathing bag was such that considerable errors would occur if apparatus resistance was assumed to be constant and so the actual apparatus resistance at each point was subtracted from the total resistance to give Raw· In conclusion, Raw is not constant throughout the respiratory cycle in infants and the pattern of change conveys additional information.

Original languageEnglish
Pages (from-to)81-93
Number of pages13
Issue number2
StatePublished - 1 Jan 1986
Externally publishedYes


  • Computer analysis
  • Lung function
  • Plethysmograph, whole-body

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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