title: Graphic analysis of flow-volume curves: a pilot study.
abstract: BACKGROUND
  Conventional spirometric parameters have shown poor correlation with symptoms and health status of chronic obstructive pulmonary disease (COPD). While it is well-known that the pattern of the expiratory flow-volume curve (EFVC) represents ventilatory dysfunction, little attempts have been made to derive quantitative parameters by analyzing the curve. In this study, we aimed to derive useful parameters from EFVC via graphic analysis and tried to validate them in patients with COPD.
  
  
  METHODS
  Using Graphical Analysis 3.4 Vernier Software, we derived from the EFVC such parameters as area of obstruction (Ao), area of triangle (AT), area of rectangle (AR) and ratio of volume at 75 and 25% peak expiratory flow (PEF) (0.25/0.75 V). For validation, we reviewed clinical and spirometric data of 61 COPD patients from Seoul National University Airway Registry (SNUAR) and Korean obstructive Lung Disease (KOLD) cohorts.
  
  
  RESULTS
  Of all parameters, only RV/TLC significantly correlated with scores from St. George's Respiratory Questionnaire (SGRQ) (r = 0.447, p = 0.037). Six-minute walking distance (6MWD) highly correlated with Ao/AR (r = -0.618, p = 0.005) and Ao/PEF (r = -0.581, p = 0.009) whereas neither FEV1 nor FEV1/FVC had significant correlation with 6MWD.
  
  
  CONCLUSIONS
  Ao/AR and Ao/PEF are promising parameters which correlate well with the exercising capacity of COPD patients.
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Division of Pulmonary and Critical Care Medicine, Seoul National University Bundang Hospital, 166, Gumi-ro, Bundang-gu, 463-707, Seongnam-si, Gyeonggi-do, Republic of Korea. lara.jlee@gmail.com.
authors.forename: Jungsil
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Division of Pulmonary and Critical Care Medicine, Seoul National University Bundang Hospital, 166, Gumi-ro, Bundang-gu, 463-707, Seongnam-si, Gyeonggi-do, Republic of Korea. ctlee@snu.ac.kr.
authors.forename: Choon-Taek
authors.initials: CT
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Division of Pulmonary and Critical Care Medicine, Seoul National University Bundang Hospital, 166, Gumi-ro, Bundang-gu, 463-707, Seongnam-si, Gyeonggi-do, Republic of Korea. jhlee7@snubh.org.
authors.forename: Jae Ho
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Division of Pulmonary and Critical Care Medicine, Seoul National University Bundang Hospital, 166, Gumi-ro, Bundang-gu, 463-707, Seongnam-si, Gyeonggi-do, Republic of Korea. lungdrcho@snu.ac.kr.
authors.forename: Young-Jae
authors.initials: YJ
authors.lastname: Cho
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Division of Pulmonary and Critical Care Medicine, Seoul National University Bundang Hospital, 166, Gumi-ro, Bundang-gu, 463-707, Seongnam-si, Gyeonggi-do, Republic of Korea. jspark.im@gmail.com.
authors.forename: Jong Sun
authors.initials: JS
authors.lastname: Park
authors.affiliation: Department of Pulmonary and Critical Care Medicine and Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. ymoh55@amc.seoul.kr.
authors.forename: Yeon-Mok
authors.initials: YM
authors.lastname: Oh
authors.affiliation: Department of Pulmonary and Critical Care Medicine and Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. sdlee@amc.seoul.kr.
authors.forename: Sang-Do
authors.initials: SD
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Division of Pulmonary and Critical Care Medicine, Seoul National University Bundang Hospital, 166, Gumi-ro, Bundang-gu, 463-707, Seongnam-si, Gyeonggi-do, Republic of Korea. dextro70@gmail.com.
authors.forename: Ho Il
authors.initials: HI
authors.lastname: Yoon
mesh_terms: D000368:Aged; D017079:Exercise Tolerance; D005260:Female; D005541:Forced Expiratory Volume; D006304:Health Status; D006801:Humans; D008297:Male; D008449:Maximal Expiratory Flow-Volume Curves / Q000502:physiology*; D008875:Middle Aged; D010865:Pilot Projects; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D013147:Spirometry; D014797:Vital Capacity