title: [Change and clinical significance of PEF in smokers, COPD and cor pulmonale patients].
abstract: OBJECTIVE
  To understand the change and clinical significance of PEF in smokers, COPD and cor pulmonale patients.
  
  
  METHODS
  The F-V curves were measured in 116 smokers, 90 COPD (43 with chronic bronchitis, 47 with emphysema) and 31 cor pulmonale patients in the ameliorated period. The indices selected were FVC, PEF, V75, V50 and V25.
  
  
  RESULTS
  The PEF% (measured values/predicted values) in smokers and chronic bronchitis patients were higher than 84%(i.e. percentages being within the normal range); they were 44% and 32% in patients with emphysema and cor pulmonale respectively and decreased with the severity of disease. The [formula: see text] (%) in smokers and chronic bronchitis patients were 87.7%-89.7% (again, percentages being within the normal range); they were 70.7% and 41.9% in patients with emphysema and cor pulmonale respectively and decreased with the severity of disease. The phenomenon that decrease was more conspicuous in V75% than in PEF% could be explained with the wave-speed theory.
  
  
  CONCLUSIONS
  There is clinical significance in the degree of decrease in PEF% and [formula: see text] (%).
authors.affiliation: Department of Physiology, West China School of Predinicaland Forensic Medicine, Sichuan University, Chengdu 610041, China.
authors.forename: Guitang
authors.initials: G
authors.lastname: Huang
authors.forename: Zhengchang
authors.initials: Z
authors.lastname: Fan
authors.forename: Jianqing
authors.initials: J
authors.lastname: Wang
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010366:Peak Expiratory Flow Rate; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D011660:Pulmonary Heart Disease / Q000503:physiopathology*; D012907:Smoking / Q000503:physiopathology*