Open AccessAssessment Of Ratio Of Peak Expiratory Flow Rate To Vital Capacity For Identifying Pulmonary Fibrosis
Author(s) -
S.D. Lok,
Donald W. Cockcroft,
Alexander Simidchiev
Publication year - 2021
Publication title -
clinical and investigative medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.391
H-Index - 47
eISSN - 1488-2353
pISSN - 0147-958X
DOI - 10.25011/cim.v44i1.35976
Subject(s) - medicine , spirometry , pulmonary function testing , cystic fibrosis , lung volumes , air trapping , lung , cardiology , vital capacity , lung function , radiology , nuclear medicine , diffusing capacity , asthma
Background: Pulmonary fibrosis (PF) is associated with reduction in vital capacity (VC) and increase in expiratory flow rates, including peak expiratory flow (PEF). Full pulmonary function testing and computed tomography chest scans are limited resources in some geographic areas and a simple and sensitive screening test would be of value. We hypothesized that increase in the ratio of % predicted PEF over % predicted VC (%PEF/%VC), from spirometry alone might be sensitive to screen for pulmonary fibrosis.
Methods: The %PEF/%VC from 1,000 consecutive spirometric flow volume curves was nearly normally distributed: 7.5% (approximately 1.5 standard deviations) had a ratio ≥ 1.4. We evaluated the sensitivity and specificity of this cut point for a diagnosis of PF in a retrospective chart review of 391 patients with good quality spirometry and respirologists’ confirmed diagnoses.
Results: Of the 391 patients analyzed, 98 had PF, 79 were normal, 70 had a combined obstructive and restrictive processes, 57 had obstructive lung disease, 61 had extra-parenchymal restriction and 26 had non-fibrotic interstitial lung disease. A %PEF/%VC ≥ 1.4 was only 54.1% sensitive in predicting PF, however it had a specificity of 94.9%. There was a 95.1% specificity for ruling in intra-parenchymal opposed to extra-parenchymal restriction.
Conclusion: A %PEF/%VC ≥ 1.4 was not sensitive enough to screen for PF but did demonstrate high specificity and thus may be helpful in identifying intraparenchymal restriction.