EUCAPNIC VOLUNTARY HYPERVENTILATION FOR THE DIAGNOSIS OF EXERCISE-INDUCED BRONCHOSPASM IN A COMMUNITY SETTING

Abstract

SESSION TITLE: Wednesday Abstract Posters SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/23/2019 09:45 AM - 10:45 AM PURPOSE: Exercise-induced bronchospasm (EIB) is a common and well-known condition affecting 5% to 20% of the general population and up to 90% of patients with symptomatic asthma. EIB tends to be treated in a community setting based on symptoms without objective findings of bronchospasm. Eucapnic voluntary hyperventilation (EVH) has been established as a sensitive test to diagnose EIB in elite athletes enrolled in research settings or in University based academic medical centers. However, clinical utility of EVH in a community practice setting has not yet been fully demonstrated. We evaluated the feasibility and performance of EVH as a diagnostic test for EIB in a community based pulmonary clinic. METHODS: Retrospective analysis of 22 EVH tests performed for evaluation of EIB symptoms. All tests were done in the pulmonary clinic at The Oregon Clinic using a standard protocol (Anderson SD, Br J Sport Med 2001). Patients underwent baseline spirometry followed by breathing a gas mixture of 5% CO2, 74% N, and 21% O2 at a target minute ventilation (35 x FEV1) for 6 minutes. Spirometry was performed at 3, 5, 10, 15, and 20 minutes. An EVH test was considered sufficient if maximum voluntary ventilation per minute (MVV) >60%. A positive test was defined as >10% decrease in any post-EVH FEV1. RESULTS: 22 patients completed EVH with 21/22 (95.4%) able to achieve MVV >60%. Mean age was 37 years, with a range of 15-71. 59% of patients were female. 4/21 (19%) of patients had a positive test for EIB. Abnormal inspiratory flow volume loops were found in 11 (50%) of patients, suggestive of vocal cord dysfunction (VCD). Videolaryngoscopy (VLS) was subsequently performed on 9 of these 11 patients, with 100% (9/9) (+) for exercise induced VCD (EIVCD) .One patient had a (+) EVH for EIB and an abnormal flow volume loop with a subsequent (+) VLS for EIVCD. CONCLUSIONS: Eucapnic Voluntary Hyperventilation has, to this point, largely been used in research and University academic medical centers to diagnose EIB. Our data suggests that EVH can be utilized successfully in a community based practice setting with the majority of athlete and non-athlete patients able to complete the test with sufficient MVV. Only 19% of patients presenting with symptoms consistent with EIB, were objectively diagnosed with EIB via EVH. This suggests EIB may be over diagnosed in the community setting based on symptoms alone. 50% of the patients evaluated with an EVH test had abnormal flow volume loops with 80% of these patients (+) for EIVCD via VLS testing. CLINICAL IMPLICATIONS: Thus, our data suggests that EVH is an acceptable diagnostic modality for EIB in a community setting, and may be useful in diagnosing alternative conditions such as EIVCD causing similar symptoms. DISCLOSURES: No relevant relationships by Crystal Clark, source=Web Response No relevant relationships by Jordan Lauw, source=Web Response No relevant relationships by John Mastronarde, source=Web Response No relevant relationships by Brandon Temte, source=Web Response No relevant relationships by Jason Wells, source=Web Response