Spirometry testing standards in spinal cord injury.
OBJECTIVE
Because muscle paralysis makes it uncertain whether subjects with spinal cord injury (SCI) can perform spirometry in accordance with American Thoracic Society (ATS) standards, determinants of test failure were examined.


METHODS
Cross-sectional study.


METHODS
Veterans Affairs (VA) medical center.


METHODS
Veterans with SCI at VA Boston Healthcare System and nonveterans recruited by mail and advertisement.


RESULTS
Two hundred thirty of 278 subjects (83%) were able to produce three expiratory efforts lasting > or = 6 s and without excessive back-extrapolated volume (EBEV). In 217 of 230 subjects (94%), FVC and FEV(1) were each reproducible in accordance with 1994 ATS standards. In the remaining 48 subjects, efforts with smooth and continuous volume-time tracings and acceptable flow-volume loops were identified. These subjects had a lower percentage of predicted FVC, FEV(1), and maximum expiratory and inspiratory pressures compared to the others, and a greater proportion had neurologically complete cervical injury (42% compared to 16%). In 19 subjects (40%), some expiratory efforts were not sustained maximally for > or = 6 s but had at least a 0.5-s plateau at residual volume (short efforts). In eight subjects (17%), some efforts were not short but had EBEV. In the remaining 21 subjects (44%), some efforts were short, some had EBEV, and some had both. If these efforts were not rejected, 262 of 278 subjects (94%) would have produced three acceptable efforts, and in 257 subjects (92%), the efforts were reproducible.


CONCLUSIONS
Subjects with SCI with the most impaired respiratory muscles and abnormal pulmonary function are able to perform spirometry reproducibly despite not meeting usual ATS acceptability standards. Exclusion of these subjects would lead to bias in studies of respiratory function in SCI. The modification of spirometry testing standards to include efforts with EBEV and with a 0.5-s plateau if < 6 s would reduce the potential for bias.
Kelley
Alyson
A
Pulmonary and Critical Care Medicine Section, Medical Service, and Rehabilitation Medicine Service, VA Boston Healthcare System, West Roxbury, MA 02132, USA.
Garshick
Eric
E
Gross
Erica R
ER
Lieberman
Steven L
SL
Tun
Carlos G
CG
Brown
Robert
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D012015:Reference Standards; D015203:Reproducibility of Results; D013119:Spinal Cord Injuries; D013147:Spirometry / Q000592:standards*