Accuracy of spirometric and flow-volume indices obtained by digitizing volume-time tracings

C. R. O'Donnell, S. L. Sneddon, Marc B Schenker, E. Garshick, F. E. Speizer, J. Mead

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


We tested the accuracy of a new system for deriving standard spirometric indices, maximal expiratory flow rates, and slope ratios from volume-time tracings. A computer-based technique employing a hand-operated cursor was used to put discrete values of volume and time into a memory array. Spirometric values obtained on 102 subjects using the computer system were compared with the corresponding 'hand-read' values. The differences between the 2 measuring techniques were not significant for the FVC, the FEV75, and the FEF25-75; however, the average FEV1 different by 6.7 ml (SD, 20.3 ml), which was significant. In addition, 10 subjects performed FVC maneuvers through a spirometer and flowmeter connected in series. Flows and slope ratios obtained from the volume-time tracings were compared with those obtained directly from the flowmeter. There was a high degree of correlation between the 2 types of flow measurements (r = 0.989), whereas slope ratios were less well correlated (r = 0.589). Configurational detail such as the presence of 'bumps' on slope ratio versus volume plots were recovered with the computer technique. Using this new system, it is possible for 1 operator to process 10 to 12 sets of spirometry tracings per hour.

Original languageEnglish (US)
Pages (from-to)108-112
Number of pages5
JournalAmerican Review of Respiratory Disease
Issue number1
StatePublished - 1987
Externally publishedYes

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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