Correlation of Oropharyngeal Pepsin and Gastroesophageal (GE) Reflux

The purpose of this research study is to see if GE reflux events are associated with
increasing levels of pepsin in spit samples. Pepsin is a special protein called an "enzyme"
that is made only in your stomach. It is not normally found in your throat. Pepsin breaks
down food proteins that you eat to form nutritional building blocks that your body can use
to grow. An enzyme is a substance that helps break down proteins.

Gastroesophageal reflux disease (GERD) is very common in infants and children, but can
result in serious health problems if not accurately diagnosed. The investigators currently
do not have a definitive test to be used as a standard for diagnosing pediatric GERD.

Measurement of pepsin, an enzyme normally produced only in the stomach, has been used as a
non-invasive way to detect gastric aspiration (reflux of stomach fluid into the airway) in
both adults and children, but using pepsin to detect reflux has not been tested. Since
pepsin should not be present in the normal esophagus and respiratory tract, but is always
present in reflux fluid from the stomach, the investigators believe that the more GE reflux
the investigators detect, the higher the levels of pepsin the investigators see in the fluid
collected from the mouth. If patients do not have GE reflux, but have swallowing problems
alone in which food or liquid goes into the airway, the investigators expect that these
patients will have no pepsin in the fluid collected from their mouth.

The investigators will test these hypotheses by measuring pepsin levels from mouth fluid and
comparing them with the number of GE reflux events the investigators find using the
pH/impedance (MII (multichannel intraluminal impedance)) test. Since the investigators are
interested in pepsin levels for all types of reflux - acid and non-acid -the investigators
will study children whether or not they are on acid blocking medicines. The investigators
will also look at pepsin levels in patients whose pH/MII is normal, but have aspiration
alone that the investigators find on a modified barium swallow (MBS) study. The
investigators will measure pepsin levels in healthy children with no reflux symptoms and no
swallowing problems as the investigators controls. The investigators anticipate that this
study will show a positive correlation between GE reflux events and the presence of
oropharyngeal pepsin, which may allow us to use pepsin as a way to test for reflux.