Exploratory Study of Potential Pulmonary Aspiration Markers From Bronchoalveolar Lavage Fluid

This study is a single center, prospective, observational study of determining pepsin levels
in BALF samples obtained from consecutive bronchoscopies at the Mayo Clinic Jacksonville. It
is inherently an exploratory pilot study to confirm whether pepsin in BAL can act as a
marker of gastric to pulmonary aspiration and whether specific association to pulmonary
pathologies can be identified.

As an overview, all patients who are undergoing a bronchoscopy for clinical indications will
be screened for potential participation in the study by obtaining BALF samples during the
procedure for laboratory analyses. The BALF will then be tested for pepsin at the Thoracic
Diseases Research Unit (Mayo Clinic Rochester) using a commercially available ELISA kit, and
the ancillary markers will be analyzed per the clinical laboratory. Internal controls will
be defined as normals when subjects have no lung dysfunction, no respiratory symptoms, and
no lung parenchymal infiltrates on chest radiographs.

The primary aims of this project parallels the short-term hypotheses stated above:

1. Confirm pepsin can be detected and quantitated in BALF obtained during a routine
bronchoscopy.

2. Identify specific pulmonary pathologies that are more often associated with increased
pepsin BAL levels.

3. Identify a normal range of pepsin in BALF in control normals.

4. Identify any correlation of pepsin BAL levels with reflux, swallow, or respiratory
symptoms (standardized questionnaires).

5. Identify any correlation between pepsin BAL levels and lung function test or
radiographic abnormalities.

Secondary aims of the study will include exploratory analyses of lesser defined potential
aspiration markers including bilirubin, lipase, amylase, and pepsinogen. Analyses of these
markers will parallel the analyses performed for pepsin.

The focus of the study is to:

- definitively identify whether pulmonary aspiration is occurring;

- quantitate the burden of aspiration that is occurring (i.e., dose);

- localize from where aspiration is occurring (e.g., gastric, duodenal, biliary,
oropharyngeal, nasal);

- identify what is specifically being aspirated (e.g., acid, exogenous oils, bacteria,
gastric contents, bile, gastric enzymes, pancreatic enzymes).