Validity of Peak Expiratory Flow for Assessing Reversible Airflow Obstruction

기류 가역성 평가에 있어서 최대호기유속 측정의 유용성

  • Chol, Won-Il (Department of Internal Medicine, Keimyung University School of Medicine) ;
  • Kwak, Jin-Ho (Department of Internal Medicine, Keimyung University School of Medicine) ;
  • Kwon, Doo-Young (Department of Internal Medicine, Keimyung University School of Medicine) ;
  • Han, Seung-Beom (Department of Internal Medicine, Keimyung University School of Medicine) ;
  • Jeon, Young-June (Department of Internal Medicine, Keimyung University School of Medicine)
  • 최원일 (계명대학교 의과대학 내과학교실) ;
  • 곽진호 (계명대학교 의과대학 내과학교실) ;
  • 권두영 (계명대학교 의과대학 내과학교실) ;
  • 한승범 (계명대학교 의과대학 내과학교실) ;
  • 전영준 (계명대학교 의과대학 내과학교실)
  • Published : 2000.04.30

Abstract

Backgrounds : Assessment of the presence and degree of reversibility of airflow obstruction is clinically important in patients with asthma or chronic obstructive pulmonary disease. The measurement of peak expiratory flow(PEF) is a simple, fast, and cheap method to assess the severity of obstruction and its degree of reversibility. Assessing the reversibility of airflow obstruction by peak expiratory flow(PEF) measurements is practicable in general practice, but its usefulness has not been well investigated. We compared PEF and $FEV_1$ in assessing reversibility of airflow obstruction in patients with chronic obstructive pulmonary disease or asthma and developed a practical criterion for assessing the presence of reversibility in general practice. Methods : PEF measurements were performed (Spirometry) in 80 patients(aged 24-78) with a history of asthma or chronic obstructive lung disease before and after the inhalation of 200 g salbutamol. The change in PEF was compared with the change in forced expiratory volume in one second($FEV_1$). Reversible airflow obstruction was analyzed according to American Thoracic Society(ATS) criteria. Results : A 12% increase above the prebronchodilator value and a 200ml increase in either FVC or $FEV_1$ reversibility were observed in 45%(36) of the patients. Relative operating characteristic(ROC) analysis showed that an absolute improvement in PEF of 30 l/min gave optimal discrimination between patients with reversible and irreversible airflow obstruction(the sensitivity and specificity of an increase of 30 l/min in detecting a 12% increase above the prebronchodilator value and a 200ml increase in either FVC or $FEV_1$ were 72.2% and 72.7% respectively, with a positive predictive value of 68.4%). Conclusions : Absolute changes in PEF can be used to diagnose reversible airflow obstruction.

Acknowledgement

Supported by : 계명대학교 동산의료원