Tuberc Respir Dis.  2003 Mar;54(3):330-337. 10.4046/trd.2003.54.3.330.

Accuracy of Spirometry at Predicting Restrictive Pulmonary Impairment

• Ahn YM
• Koh WJ
• Kim CH
• Lim SY
• An CH
• Suh GY
• Chung MP
• Kim H
• Kwon OJ

• KMID: 1970582
• DOI: http://doi.org/10.4046/trd.2003.54.3.330

Abstract

BACKGROUND: Low spirometric forced vital capacity(FVC) in conjunction with a normal or high ratio of the forced expiratory volume at 1 second to the forced vital capacity(FEV1/FVC%) has traditionally been classified as a restrictive abnormality. However, the gold-standard diagnosis of a restrictive pulmonary impairment requires a measurement of the total lung capacity (TLC). This study was performed to determine the predictive value of spirometric measurements of the FVC for diagnosing a restrictivepulmonary abnormality.
METHODS
Test results from 1,371 adult patients who undertook both spirometry and lung volume measurements on the same visit from January 1999 to December 2000 were enrolled in this study. The test values for the FVC, the TLC that was below 80% of predicted value, and a FEV1/FVC% that was below 70%, were classified as being abnormal.
RESULTS
Of the 1,371 patients, 353 patients had a reduced a FVC. Of these patients, 186 patients had a reduced TLC. Therefore, the positive predictive value was 52.7%. Of the 196 patients with a normal FEV1/FVC% and a reduced FVC, 148(75.5%) patients had a lower TLC. Thirty eight (24.2%) patients out of 157 patients with a low FEV1/FVC% and a low FVC showed a restrictive defect.
CONCLUSION
Spirometry is useful to rule out a restrictive pulmonary abnormality, but a restrictive pattern on the spirometry dose not mean there is a true restrictive disease. For the patients with a low FVC, TLC measurements are essential for diagnosing a restrictive pulmonary impairment.

Keyword

Respiratory function tests; Lung volume measurements; Total lung capacity; Vital capacity; Spirometry; Whole body plethysmography

MeSH Terms

Adult
Diagnosis
Forced Expiratory Volume
Humans
Lung Volume Measurements
Plethysmography, Whole Body
Respiratory Function Tests
Spirometry*
Total Lung Capacity
Vital Capacity