Noninvasive Lung Clearance Index Test Shows Promise
A test called the lung clearance index (LCI) is superior to standard tests in identifying patients with lung disease related to military deployment, suggests a study in the August 2017 Journal of Occupational and Environmental Medicine
Silpa Dhoma Krefft, MD, MPH, of National Jewish Health, Denver, and colleagues evaluated the LCI as a test for deployment-related lung disease. An "unknown number" of military personnel deployed to Iraq and Afghanistan have developed respiratory symptoms unexplained by traditional lung function tests and chest CT scans. This condition may be linked to burn pit emissions, desert dust, and other exposures during deployment.
The LCI detects abnormalities of the small airways; it is most often used to assess early lung damage in children with cystic fibrosis (CF). The researchers evaluated its use in 28 patients with definite (17 cases) or probable (11 cases) deployment-related lung disease. Currently, a surgical sample of lung tissue (biopsy) is needed to confirm the diagnosis.
The average LCI score was were higher for patients with symptoms of deployment-related lung disease, compared to a non-deployed control group. The difference narrowed and become nonsignificant on adjustment for age, body mass index, and smoking.
An abnormal LCI score was more sensitive in identifying patients with deployment-related lung disease, compared to standard lung function tests or CT scans. An elevated LCI score was also a better indicator of abnormal results on lung biopsy.
A noninvasive test such as the LCI could be a major advantage in detecting underlying lung disease in veterans with respiratory symptoms. Dr. Krefft and coauthors note the lack of "normative data" on LCI results in healthy adults — most previous studies of this test have focused on younger patients with CF.
With further research, the LCI might prove useful in monitoring for stability or progression of deployment-related lung disease. It might also aid in assessing small airway abnormalities in larger groups of patients at risk of other occupational lung diseases.
About the Author — Dr. Krefft may be contacted for interviews at KrefftS@NJHealth.org
About ACOEM — The American College of Occupational and Environmental Medicine (www.acoem.org), an international society of 4,500 occupational physicians and other health care professionals, provides leadership to promote optimal health and safety of workers, workplaces, and environments.
— The Journal of Occupational and Environmental Medicine
(www.joem.org) is the official journal of the American College of Occupational and Environmental Medicine. Edited to serve as a guide for physicians, nurses, and researchers, the clinically oriented research articles are an excellent source for new ideas, concepts, techniques, and procedures that can be readily applied in the industrial or commercial employment setting.
Krefft SD, Strand M, Smith J, Stroup C, Meehan R, Rose C. Utility of lung clearance index testing as a noninvasive marker of deployment-related lung disease. J Occup Environ Med. 2017;59(8):707-11.