Validity of peak expiratory flow for assessing the presence of airflow obstruction / 대한내과학회지

BACKGROUND: Since there has been strong correlation between peak expiratory flow (PEF) and forced expiratory volume in one second (FEV1), assessing the presence of airflow obstruction by PEF measurements would be useful in general practice, but its usefulness has not been well investigated. We hypothesize that PEF would be practicable for assessing the presence of airflow obstruction. METHODS: PEF measurements were performed mini-Wright peak flow meter in 106 patients (aged 19-82) with a history of asthma or chronic obstructive lung disease. The change in PEF (% predicted value) was compared with the change in FEV1 and forced expiratory volume in one second to forced vital capacity ratio (FEV1/FVC). Airflow obstruction was analyzed according to European Community for Coal and Steel criteria. When defined as an FEV1 and FEV1/FVC ratio both below the 90% confidence interval of predicted values before bronchodilator. RESULTS: Airflow obstruction was observed in 76.4% (81) of patients. Relative operating characteristic analysis showed that an below in PEF of 60% of predicted value gave optimal discrimination between patients with no airflow obstruction and airflow obstruction (the sensitivity and specificity of below 60% of predicted value in detecting FEV1 and FEV1/FVC ratio both below the 90% confidence interval of predicted values were 86.4% and 83.0% respectively, with a positive predictive value of 94.5%) CONCLUSION: Percentage of predicted value in PEF could be used to diagnose airflow obstruction.

The Time Responses of Spirometric Values in Response to Single Doses of Inhaled Salbutamol / 결핵

BACKGROUND: An assessment of the presence and the degree of reversibility of airflow obstruction is clinically important in patients with asthma or chronic obstructive pulmonary disease. However, the time responses of spirometric parameters in response to bronchodilator have not been well investigated. METHODS: We studied 15 patients with asthma. Spirometric and mini-Wright peak expiratory flow measurements were performed at 15, 30, 45, and 60 minutes after using single dose(200 micro gram) of inhaled bronchodilator, salbutamol. RESULTS: The mean values of forced expiratory volume in one second(FEV1) and forced vital capicaty(FVC) were significantly increased at 60 minutes after using bronchodilator in comparison to 15 minutes. And peak expiratory flow rate measured by either mass flow sensor or mini-Wright peak flow meter were significantly increased at 45 minutes after using bronchodilator in comparison to 15 minutes. CONCLUSIONS: To appropriate evaluation of the bronchodilator response in patients with reversible airflow limitation, it would be useful measuring either FEV1 or PEF at the later time point 60 or 45 minutes in comparison to 15 minutes after using bronchodilator.