Herrera-Sánchez Andrea, Álvarez-Chávez Fabián Eduardo, Castillo-Hernández María C, Orihuela Óscar, Guevara-Balcázar Gustavo, Martínez-Godínez María Ángeles, González-Virla Baldomero
Instituto Mexicano del Seguro Social, Centro Médico Nacional Siglo XXI, Hospital de Especialidades, Ciudad de México, México.
Rev Alerg Mex. 2019 Jul-Sep;66(3):308-313. doi: 10.29262/ram.v66i3.630.
The diagnosis of asthma is confirmed with a spirometry: FEV1 ratio (forced expiratory volume in one second)/FVC (forced vital capacity) <80% with reversibility (FEV1 >12% or 200 mL) after using salbutamol. The peak expiratory flow is cheap and easy to use; it measures the forced expiratory flow, of which reversibility > 20% suggests asthma.
To know the sensitivity, specificity, and the positive and negative predictive values of the flowmeter.
A cross-sectional, observational, comparative study. Individuals aged >18 years without contraindications for spirometry were included. They underwent spirometry and peak expiratory flow, and the ACT (Asthma Control Test) questionnaire was applied to them. Sensitivity, specificity, positive predictive value and negative predictive value of the flowmetry were calculated. ROC curve was carried out in order to know the cut-off point of greater sensitivity and specificity.
Of 150 patients, 66% were male; the median age was 38 years. According to the guidelines of GINA 2018 (Global Initiative for Asthma); 58.7% were controlled. The sensitivity of the peak expiratory flow was 47%, and the specificity was 87%, with a positive predictive value of 54.8% and a negative predictive value of 84%. The peak expiratory flow showed higher specificity with FEV1 <59%. The cut-off point of greater sensitivity and specificity was a reversibility of 8%, with an area under the curve of 0.70.
The flowmeter has got greater sensitivity in airway obstructions; it is useful when a spirometer is not available.
哮喘的诊断通过肺功能仪来确认：使用沙丁胺醇后，一秒用力呼气量（FEV1）/用力肺活量（FVC）比值<80%且具有可逆性（FEV1增加>12%或200毫升）。呼气峰值流速测量方法廉价且易于使用；它测量用力呼气流量，其可逆性>20%提示哮喘。
了解呼气峰值流速仪的敏感性、特异性以及阳性和阴性预测值。
一项横断面、观察性、对比研究。纳入年龄>18岁且无肺功能仪检查禁忌证的个体。他们接受了肺功能仪检查和呼气峰值流速测量，并填写了哮喘控制测试（ACT）问卷。计算呼气峰值流速测量的敏感性、特异性、阳性预测值和阴性预测值。绘制ROC曲线以确定具有更高敏感性和特异性的切点。
150例患者中，66%为男性；中位年龄为38岁。根据2018年全球哮喘防治创议（GINA）指南，58.7%的患者病情得到控制。呼气峰值流速的敏感性为47%，特异性为87%，阳性预测值为54.8%，阴性预测值为84%。当FEV1<59%时，呼气峰值流速显示出更高的特异性。具有更高敏感性和特异性的切点是可逆性为8%，曲线下面积为0.70。
呼气峰值流速仪在气道阻塞方面具有更高的敏感性；在没有肺功能仪的情况下很有用。
