Pepsin As A Biomarker For Aspiration

Aspiration is well recognized in children who have chronic lung disease or who are
intubated. There is a known association between gastroesophageal reflux (GER) and
aspiration. The distinction between aspiration of swallowed material, such as food and the
aspiration of refluxed gastric contents is important. Determining whether an aspiration
syndrome in an individual is due to GER may be difficult. The most widely used test to
determine whether GER is the cause of aspiration involves staining bronchoaveolar lavage
(BAL) fluid for lipid laden macrophages (LLM) based on the hypothesis that refluxed and
aspirated fluid is phagocytosed by tracheal macrophages.

Pepsinogen is a protein unique to gastric chief cells and also requires acidic conditions
for activation. Therefore the presence of pepsin in BAL fluid should only be found when
gastric fluid is aspirated. In previous studies, pepsin has been detected in the tracheal
fluid of children with chronic lung disease. Thus far, studies of this material have been
small, not all have control groups, and LLM were not looked for in all studies.

Based on previous studies and the need to improve diagnostic methods, the following aims are
proposed:

1. to determine the frequency of pepsin contamination of children without chronic
respiratory disease undergoing elective surgery with intubation

2. to determine frequency of tracheal pepsin and lipid laden macrophages (LLM) in

1. children undergoing bronchoscopy; or with tracheostomies, or that are intubated

2. critically ill, intubated children; and

3. children with tracheostomies

3. to compare the presence or absence and concentration of pepsin to the presence of LLM

4. to relate the presence or absence and concentration of pepsin to clinical status To
achieve these aims, BAL fluid will be obtained from subject patients and controls.
These fluids will be transported to the research lab and stored on ice until analysis.
Determination of LLM will be done in children undergoing diagnostic bronchoscopy in the
clinical lab of CHW per routine. BAL analysis will consist of Western blot staining
for the presence of pepsin. Demographic data will also be collected from the medical
record.

Inclusion Criteria:

- Meet criteria of study population

Exclusion Criteria:

- Lack of informed consent/assent

- Pulmonary disease in normal controls