Elsevier

Respiratory Medicine

Volume 100, Issue 8, August 2006, Pages 1397-1401
Respiratory Medicine

Comparison of FEV6 and FVC for detection of airway obstruction in a community hospital pulmonary function laboratory

https://doi.org/10.1016/j.rmed.2005.11.012Get rights and content
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Summary

The National Lung Health Education Program recommends that primary care providers perform spirometry tests on cigarette smoking patients 45 years or older in order to detect airways obstruction and aid smoking cessation efforts [Ferguson GT, Enright Pl, Buist AS, et al. Office spirometry for lung health assessment in adults: a consensus statement from the national lung education program. Chest 2000; 117: 1146–61]. An abbreviated forced expiratory maneuver that requires exhalation for 6 s (FEV6) has recently been proposed as a substitute for forced vital capacity (FVC) to facilitate performance of such spirometry. We set out to assess the accuracy of diagnosis of obstruction and abnormal pulmonary function using FEV6 in comparison to FVC in a community hospital population. One hundred pulmonary function tests performed at a community hospital were randomly selected and retrospectively analyzed. Sixty-three of the 100 tests had satisfactory 6-s expiration and were subject to further analysis. We compared the spirometric interpretation using Morris predictive equations for FEV1/FVC and Hankison predictive equations for FEV1/FVC and FEV1/FEV6. The Hankison set of equations is the only published reference formulas for prediction of FEV6. We found that versus our Morris gold standard, Hankison based FEV1/FVC interpretation was 100% sensitive and 67% specific for the diagnosis of obstruction and 100% sensitive and 65% specific for the diagnosis of any abnormality. The Hankison based FEV1/FEV6 interpretation was 97% sensitive and 47% specific for diagnosing obstruction and 100% sensitive and 50% specific for identifying any abnormality versus the Morris FVC based gold standard. In conclusion, in our hospital based pulmonary function laboratory, FEV6 based interpretation has excellent sensitivity for detection of spirometric abnormalities. However, its moderate specificity may hinder its utility as a screening test. Further testing is necessary to determine its reliability in different patient populations with less highly trained operators.

Keywords

Spirometry
Pulmonary function test
Smoking cessation
Chronic obstructive pulmonary disease

Abbreviations

ATS
American Thoracic Society
BTPS
body temperature
ambient pressure
and saturated with water vapor
FEV1
forced expiratory volume at 1 s
FEV1/FEV6
forced expiratory volume at 1 s divided by forced expiratory volume at 6 s gives a ratio used to diagnose obstruction
FEV1/FVC
forced expiratory volume at 1 s divided by forced vital capacity gives a ratio used to diagnose obstruction
FEV6
forced expiratory volume at 6 s
FVC
forced vital capacity
PFT
pulmonary function test

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