Presence of variable extrathoracic airflow limitation in patients with a negative methacholine challenge test

• Published in: Allergy, asthma, and clinical immunology asthma, and clinical immunology, 2023-11, Vol.19 (1), p.1-101, Article 101
• Main Authors: Elfessi, Zane Z., Zavala, Sarah, Rubinstein, Israel
• Format: Article
• Language: English
• Subjects: Cough; Electronic health records; FEF50/FIF50; Inducible laryngeal obstruction; Obesity; Obstructive sleep apnea; Short Report; Sleep apnea; Spirometry
• ISSN: 1710-1492; 1710-1484; 1710-1492
• DOI: 10.1186/s13223-023-00860-w

PurposeDetermine whether variable extrathoracic airflow limitation (VEAL) is observed in patients with negative methacholine challenge tests (MCT).MethodsElectronic medical records of patients undergoing MCT at Jesse Brown VA Medical Center between January 2017 and December 2019 were reviewed. Only patients with negative MCT were selected. Pertinent demographic, clinical, and pulmonary function tests (PFT) and MCT data were abstracted from each record. Spirometric flow-volume loops recorded during each test were inspected by one co-author to determine the first inhaled methacholine concentration at which FEF50/FIF50 was either > 1 or further increased if baseline FEF50/FIF50 after nebulized saline (vehicle) already exceeded 1. Student’s t-test was used for statistical analysis. P  1 after testing. They were predominately obese (BMI, 31.3 ± 6.6), non-smoking (10), White (8) males (9) aged 51.3 ± 14.1 years (mean ± SD) referred for symptoms suggestive of asthma (n = 7) or for chronic cough (n = 6). Five had obstructive sleep apnea, three gastroesophageal reflux disease, and two chronic rhinosinusitis. FEF50/FIF50 increased significantly from 0.72 ± 0.21 after nebulized saline (vehicle) to 1.21 ± 0.13 after inhaled methacholine (p