Identifying Undiagnosed Airway Dysfunction in WTC Responders Using Respiratory Oscillometry

Albert Einstein College Of Medicine, Bronx NY

Investigators

Abstract

Project Summary Rescue/recovery work at the World Trade Center (WTC) disaster site is associated with many physical health outcomes, including respiratory conditions.1-10 While over 6,230 of the Fire Department of the City of New York (FDNY) WTC-exposed rescue/recovery workers have a diagnosis of obstructive airway disease (OAD), preliminary analyses show 43% with respiratory symptoms do not have a clear diagnosis to explain their symptoms, leaving an area of diagnostic and treatment uncertainty. Although spirometry is the most common pulmonary function test used to evaluate WTC-exposed individuals, many with respiratory symptoms have normal spirometry. Several studies in WTC-exposed community members and ironworkers have suggested that persistent respiratory symptoms after WTC exposure are likely due to small airway dysfunction (i.e., airways <2 mm in diameter) which is not well characterized using spirometry.11-20 Alternatively, respiratory oscillometry is a non-invasive, effort independent, low-cost method for measuring the mechanical properties of the respiratory system that is especially useful in measuring small airway function. Beginning in 2013, a subset of FDNY rescue/recovery workers underwent respiratory oscillometry testing and spirometry, both performed on the same day. Our proposed study is an opportunity to analyze these data and explore if abnormal respiratory oscillometry measurements, including small airway measurements, explain the reason for respiratory symptoms in the FDNY cohort who remain without a clear respiratory diagnosis; thereby, potentially expanding upon current findings in WTC-exposed community member and ironworker cohorts. Specifically, we will focus on those with normal spirometry who have respiratory symptoms, thus, continue to have diagnostic uncertainty. In these cases, normal spirometry results present challenges in diagnosing and treating conditions like asthma and chronic obstructive pulmonary disease (COPD), highlighting the need for alternate testing modalities to diagnose airway dysfunction. This proposal aims to determine if respiratory oscillometry can identify airway dysfunction among symptomatic WTC-exposed FDNY responders with diagnostic uncertainty. By resolving this uncertainty, earlier treatment interventions could be implemented, potentially reducing respiratory symptom-related morbidities. First, we will examine the relationship between airway resistance, as measured by respiratory oscillometry, and respiratory symptom characteristics and severity. Then, we will investigate if abnormal respiratory oscillometry, in those with normal baseline spirometry measured at the same time, predicts future spirometry abnormalities. Because OAD treatment modalities can differ based on the presence of eosinophilia, we will also explore if blood eosinophilia is associated with abnormal respiratory oscillometry in individuals with normal spirometry. By carrying out this proposed project we will address diagnostic uncertainty in airway dysfunction among WTC-exposed individuals.