Diagnostic Value of Astograph Airway Responsiveness Measurement in Chest Suffocation Variant Asthma

Abstract

Objective To investigate the diagnostic value of Astograph methacholine provocation test in patients with chest tightness variant asthma(CTVA). Methods From January 2011 to February 2017, 156 patients with CTVA in outpatient or inpatient department of respiratory medicine of Kailuan General Hospital affiliated to North China University of Science and Technology were selected as case group (chest tightness variant asthma group). The control group were 361 non-asthmatic patients including interstitial lung disease(23 cases), coronary disease (157 cases), hypertensive cardiopathy(22 cases), myocardiosis (16 cases), congenital heart disease (3 cases), rheumatic valvular heart disease (6 cases), central airway disease (3 cases), thyromegaly (10 cases), mediastinal tumor (5 cases), thoracic or spinal deformity (8 cases), phrenoparalysis (2 cases) and vegetative nerve functional disturbance (106 cases). All participants received pulmonay ventilation test, average daily and nightly variation rate of PEF(Peak expiratory flow) or PEF weekly variability, Astograph methacholine provocation test (forced expirataory volume in one second≥70% expectation), and other relevant examinations.The diagnostic value of Astograph methacholine provocation test on CTVA was assessed by analyzing the sensitivity, specificity, positive predictive value, negative predictive value, and Yunden index of Astograph methacholine airway. Results Compared with the control group((1.18±0.44)%), theforced expiratory flow from 75% of Forced vital capcacity (FEF75)index of CTVA group((1.29±0.50)%) had significant difference(, t=2.96, P=0.006). The sensitivity, specificity, positive predictive value, negative predictive value, Yunden index, and diagnostic accuracy of Astograph methacholine provocation test on CTVA were 0.814, 0.695, 0.536, 0.305, 0.509 and 0.731, respectively. Conclusion The sensitivity, negative predictive value, Yunden index and diagnostic accuracy of Astograph methacholine provocation test on CTVA were higher, whereas the specificity and positive predictive value were relatively lower, suggesting that Astograph methacholine provocation test had a reliable diagnostic value on CTVA, with lower false negative and higher false positive. Key words: Astograph method; Chest tightness variant asthma; Diagnosis