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Poster Presentations: Wednesday, November 3, 2010 |

Determination of Airway Hyperreactivity in Patients With Obstructive Spirometric Indices and FEV1 > 90% Predicted FREE TO VIEW

Tokunbo J. Matthews, MD; George Kotti, MD; David Bell, MD; Michael Morris, MD
Author and Funding Information

Wilford Hall Medical Center, San Antonio, TX



Chest. 2010;138(4_MeetingAbstracts):558A. doi:10.1378/chest.10667
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Published online

Abstract

PURPOSE: A prior retrospective study determined that a normal forced expiratory volume in one second (FEV1) > 90% predicted with obstructive indices may not represent a normal variant as 11% of patients were found to have underlying airway hyperreactivity. This study sought to prospectively determine if patients with an FEV1 > 90% and obstructive indices have objective evidence of airway hyperreactivity based on multiple measures of lung function.

METHODS: Pulmonary function testing (PFTs) databases were reviewed on a monthly basis and patients with technically adequate spirometry studies were enrolled in the study based on an FEV1 > 90% predicted and a forced expiratory volume in one second to forced vital capacity ratio (FEV1/FVC) below the lower limit of normal based on 95th percentile confidence intervals. All patients underwent a standardized evaluation to include full PFTs, post-bronchodilator testing, impulse oscillometry, methacholine challenge testing, and exhaled nitric oxide analysis to evaluate for the presence of airway hyperreactivity.

RESULTS: To date, six patients (4 females, 2 males) have been enrolled in the protocol and completed testing procedures. PFTs demonstrated a mean FEV1 (% pred) = 92.6%, FVC (% pred) = 103.9%, FEV1/FVC = 70.9%; TLC (% pred) = 105.7%, RV(% pred) = 85.7%, and DLCO (% pred) = 79.2%. None of the patients meet the 12% criteria for positive bronchodilator testing with a mean FEV1 increase of 7.2%. Methacholine challenge testing was positive in only one patient. Impulse oscillometry values at 5 Hz/20 Hz and exhaled nitric oxide analysis values were not consistent with the presence of airway hyperreactivity.

CONCLUSION: The majority of patients with an obstructive indices and elevated FEV1 > 90% do not have airway hyperreactivity based on post-bronchodilator and methacholine challenge testing despite the presence of airway symptoms such as cough and dyspnea.

CLINICAL IMPLICATIONS: A normal FEV1 > 90% predicted with obstructive indices may not consistently represent a normal physiological variant. Based on airway symptoms, clinicians should evaluate for airway hyperreactivity even in the presence of an elevated FEV1.

DISCLOSURE: Tokunbo Matthews, No Financial Disclosure Information; No Product/Research Disclosure Information

12:45 PM - 2:00 PM


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