Nikhil A Huprikar1, Andrew J Skabelund2, Valerie G Bedsole3, Tyson J Sjulin4, Asmita V Karandikar4, James K Aden5, Michael J Morris5. 1. Pulmonary/Critical Care Service, Brooke Army Medical Center, Joint Base San Antonio (JBSA) Fort Sam Houston, Texas. nikhil.a.huprikar.mil@mail.mil. 2. Pulmonary/Critical Care Service, Wilford Hall Ambulatory Surgery Center, Lackland Air Force Base, Texas. 3. Internal Medicine Residency, Brooke Army Medical Center, JBSA Fort Sam Houston, Texas. 4. Pulmonary/Critical Care Service, Brooke Army Medical Center, Joint Base San Antonio (JBSA) Fort Sam Houston, Texas. 5. Graduate Medical Education, Brooke Army Medical Center, JBSA Fort Sam Houston, Texas.
Abstract
BACKGROUND: Obstructive lung disease is diagnosed by a decreased ratio of FEV1 to the vital capacity (VC). Although the most commonly used VC is FVC, American Thoracic Society guidelines suggest alternative VCs, for example, slow VC (SVC), may offer a more-accurate evaluation of breathing capacity. There is recent evidence that using only FEV1/FVC underrecognizes obstruction in subjects at high risk and who are symptomatic. Previous studies have indicated that healthy individuals show a minimum difference between FVC and SVC; however, testing of individuals with asthma and who are symptomatic indicates that SVC can be markedly larger than FVC. OBJECTIVE: To evaluate the differences among SVC, FVC, and SVC-based measurements in the diagnosis of symptomatic obstructive lung disease. METHODS: A retrospective analysis was performed of spirometry and plethysmography measurements from studies conducted between 2011 to 2015. We established a pulmonary function database that incorporated predictive equations from the National Health and Nutrition Examination Survey III (NHANES III). The SVC to FVC difference was calculated. FEV1/SVC was compared with FEV1/FVC by using NHANES III lower limit of normal values. RESULTS: A total of 2,710 studies with 2,244 subjects were reviewed. Spirometric obstruction, as defined by NHANES III, was identified in 26.1% of the studies (707/2,710). The mean (± SD) difference between SVC and FVC was 375.0 ± 623.0 mL and 258.8 ± 532.5 mL in those with and those without obstruction, respectively. Subgroup and multivariate analysis demonstrated age, body mass index, and FEV1 associated contributions to the difference between SVC and FVC. By using FEV1/SVC, the prevalence of obstruction increased from 26.1 to 45.0% (1,219/2,710) and identified 566 additional studies of subjects with obstruction. Fifty-four percent of the subjects with newly-identified obstructive lung disease (305/566) had smoking histories, and 67.4% (345/512) received medications for obstructive lung disease. CONCLUSIONS: The isolated use of FVC-based diagnostic algorithms did not recognize individuals with symptomatic obstructive lung disease. Recognizing the difference between SVC and FVC measurements in subjects will improve testing and diagnosis of obstructive lung disease.
BACKGROUND:Obstructive lung disease is diagnosed by a decreased ratio of FEV1 to the vital capacity (VC). Although the most commonly used VC is FVC, American Thoracic Society guidelines suggest alternative VCs, for example, slow VC (SVC), may offer a more-accurate evaluation of breathing capacity. There is recent evidence that using only FEV1/FVC underrecognizes obstruction in subjects at high risk and who are symptomatic. Previous studies have indicated that healthy individuals show a minimum difference between FVC and SVC; however, testing of individuals with asthma and who are symptomatic indicates that SVC can be markedly larger than FVC. OBJECTIVE: To evaluate the differences among SVC, FVC, and SVC-based measurements in the diagnosis of symptomatic obstructive lung disease. METHODS: A retrospective analysis was performed of spirometry and plethysmography measurements from studies conducted between 2011 to 2015. We established a pulmonary function database that incorporated predictive equations from the National Health and Nutrition Examination Survey III (NHANES III). The SVC to FVC difference was calculated. FEV1/SVC was compared with FEV1/FVC by using NHANES III lower limit of normal values. RESULTS: A total of 2,710 studies with 2,244 subjects were reviewed. Spirometric obstruction, as defined by NHANES III, was identified in 26.1% of the studies (707/2,710). The mean (± SD) difference between SVC and FVC was 375.0 ± 623.0 mL and 258.8 ± 532.5 mL in those with and those without obstruction, respectively. Subgroup and multivariate analysis demonstrated age, body mass index, and FEV1 associated contributions to the difference between SVC and FVC. By using FEV1/SVC, the prevalence of obstruction increased from 26.1 to 45.0% (1,219/2,710) and identified 566 additional studies of subjects with obstruction. Fifty-four percent of the subjects with newly-identified obstructive lung disease (305/566) had smoking histories, and 67.4% (345/512) received medications for obstructive lung disease. CONCLUSIONS: The isolated use of FVC-based diagnostic algorithms did not recognize individuals with symptomatic obstructive lung disease. Recognizing the difference between SVC and FVC measurements in subjects will improve testing and diagnosis of obstructive lung disease.
Authors: Spyridon Fortis; Alejandro P Comellas; Surya P Bhatt; Eric A Hoffman; MeiLan K Han; Nirav R Bhakta; Robert Paine; Bonnie Ronish; Richard E Kanner; Mark Dransfield; Daniel Hoesterey; Russell G Buhr; R Graham Barr; Brett Dolezal; Victor E Ortega; M Bradley Drummond; Mehrdad Arjomandi; Robert J Kaner; Victor Kim; Jeffrey L Curtis; Russell P Bowler; Fernando Martinez; Wassim W Labaki; Christopher B Cooper; Wanda K O'Neal; Gerald Criner; Nadia N Hansel; Jerry A Krishnan; Prescott Woodruff; David Couper; Donald Tashkin; Igor Barjaktarevic Journal: Chest Date: 2021-02-01 Impact factor: 10.262