Primary Outcome Measures:
- Pulmonary Function Testing [ Time Frame: 1 hour ] [ Designated as safety issue: No ]
These will include flow-volume curve, spirometry, single breath CO diffusing capacity (DcoSB), within breath diffusing capacity (DcoWB) with rapid infrared analyzer, and total lung capacity and airway resistance by body plethysmography
Secondary Outcome Measures:
- Clinical Examination (including blood pressure and electrocardiogram) [ Time Frame: 30 min ] [ Designated as safety issue: No ]
Brief physical examination, seated blood pressure measurements (three separate determinations three minutes apart) and baseline electrocardiogram
- Progressive Incremental Exercise [ Time Frame: 1 hour ] [ Designated as safety issue: No ]
The subject will be placed on the cycle ergometer and measurements of inspiratory capacity will be obtained. Then the subject will perform exercise at increasing work rates corresponding to 20%, 40%, 60%, and 80% of the maximum oxygen uptake attained in the first exercise. Inspiratory capacity will be measured twice at each work rate while recording tidal flow-volume loops to assess for evidence of airflow limitation during exercise.
- Diffusing Capacity (DcoWB) and Pulmonary Capillary Blood Flow (Qc) During Supine Cycle Exercise [ Time Frame: 30 minutes ] [ Designated as safety issue: No ]
DcoWB and Qc will be measured in duplicate at rest and during 6-minute stages, at work rates of 20%, 40%, 60%, and 80% of the maximum work rate attained in the previous incremental exercise study
- Computed Tomography (CT) Scan of Chest [ Time Frame: 40 minutes ] [ Designated as safety issue: No ]
The subjects will undergo two low dose CT scans of chest. These scan will be preformed using a 64 multi-detector GE scanner which allows for a very short scan time- a matter of several seconds for each scan. One scan will be obtained at maximum inspiration (total lung capacity or TLC) and one at maximum expiration (residual volume or RV).
This study aims to ascertain whether standard exercise stress testing can detect subclinical cardiopulmonary disability in subjects with significant exposure to second hand tobacco smoke (SHS). The ultimate goal of this study is to contribute to the understanding of SHS-related illnesses, and to the care of future patients with SHS exposure.
The main hypothesis of this study is that exposure to the secondhand tobacco smoke (SHS) in the confined workspace of commercial aircraft prior to the ban against cigarette smoking is responsible for long-term damage to the lungs of nonsmoking flight attendants. Although only some flight attendants show evidence of this damage on their lung function at rest, the majority of the flight attendants will have abnormal diffusing capacity during exercise as the damage may be too subtle to be detected with lung function measurements at rest. To test these hypotheses, we will compare pre- and post-ban flight attendants to each other and to two groups of age-matched, nonsmoking controls living at sea level stratified on the basis of SHS exposure. The results of our study should permit us to determine whether SHS alone could account for the lung damage in flight attendants, or whether some more complex interaction (involving cabin factors such as ozone, altitude, radiation and SHS) may be involve.