Progressive Decline in Plethysmographic Lung Volumes in Infants: Physiology or Technology?

G. Hulskamp, A. Hoo, H. Ljungberg, S. Lum, Jane Pillow, J. Stocks

Research output: Contribution to journalArticlepeer-review

50 Citations (Scopus)


During the last 30 years, there has been an unexplained trend toward declining values for plethysmographic assessments of lung volume at functional residual capacity (FRC) in infants. The aim of this study was to compare data collected from healthy infants using contemporary equipment with published reference data and to explore reasons for discrepancies. Lung volumes were measured in 32 healthy infants (age, 4-93 weeks; weight, 3.9-12.4 kg) using a new, commercially available infant plethysmograph. Mean (SD) FIRC was 19.6 (3.4) ml/kg (within subject coefficient of variation 3.4 [2.3%]), which was on average 7.0 [3.5] ml/kg and 2.3 [1.2] SD (Z) scores lower than the recently collated reference data from an American Thoracic Society task force. A total of 66% of these healthy infants had a FIRC that was below the predicted normal range. Comparison of equipment, software, and protocols with those from previous reports revealed the importance of minimization of dead space and of adequate subtraction of all compressible occluded volume when calculating FIRC in infants. These findings emphasize the need to establish reference data for lung function tests in infants that are appropriate for the equipment and protocols in current use.
Original languageEnglish
Pages (from-to)1003-1009
JournalAmerican Journal of Respiratory and Critical Care Medicine
Issue number8
Publication statusPublished - 2003


Dive into the research topics of 'Progressive Decline in Plethysmographic Lung Volumes in Infants: Physiology or Technology?'. Together they form a unique fingerprint.

Cite this