Effect of spirometer temperature on measurement of FEV1 shift changes.
Hankinson-JL; Castellan-RM; Kinsley-KB; Keimig-DG
J Occup Med 1986 Dec; 28(12):1222-1225
An analysis was conducted to evaluate the effects of ambient (spirometer) temperature on forced expiratory volume in 1 second (FEV1) changes over a work shift under actual field conditions. Data from 1,900 workers from 73 different sites who completed valid spirometric examinations both before and after a work shift were evaluated. Most of the examinations were conducted during the dayshift, so that the preshift temperatures were often lower that postshift temperatures. Two sets of preshift and postshift FEV1 values were calculated for each subject, one using the standard body temperature pressure saturated (BTPS) factor and the other using a dynamic BTPS correction factor. When the standard BTPS factor was used, a larger number of subjects were falsely classified as having significant (at least 5 percent) decrements in FEV1 as the spirometer temperature change increased. When the temperature rose during the shift by more than 3 degrees-C, the number of subjects with a significant decrement in FEV1 over the work shift was significantly higher when the standard BTPS correction factor was used than when the dynamic BTPS correction factor was used. The magnitude of the percent error in FEV1 decrement over the work shift increased with an increase in the magnitude of the change of the spirometer temperature over the work shift. The authors conclude that spirometer temperature, as affected by ambient temperature, may affect measurement of FEV1. Ambient spirometer temperatures should be maintained relatively constant, with a range of no more than 3 degrees-C.
JOCMA7; NIOSH-Author; Cotton-industry; Pulmonary-function-tests; Pulmonary-system-disorders; Lung-function; Temperature-effects; Workplace-studies
Journal of Occupational Medicine