Gastroesophageal reflux disease (GERD) occurs when an excessive amount
of gastric (stomach) acid regurgitates back in to the esophagus. This
diagnosis is generally made by symptom description (e.g. heartburn,
indigestion), xrays or endoscopy. On occasion however, less classic symptoms
of GERD such as chest pain, sore throat, hoarseness, night sweats or cough
make the diagnosis more difficult. In such instances, actually measuring the
frequency and duration of acid regurgiation into the esophagus is necessary
to make the appropriate diagnosis and tailor therapy. Outpatient pH
monitoring is used for such a purpose. The term "pH" refers to the level or
degree of acidity. By placing a thin acid-sensitive catheter through the
nose and into the esophagus, the pH, or acid level, is measured and
transmitted to an attached monitoring device. The lightweight monitor is
carried on the patient's belt or over the shoulder for a period of up to 24
hours, recording pH levels and time on an ongoing basis. Symptoms are logged
by the patient, as is the time they occcured, time of meals, and body
position (supine vs. upright). when the pH tracing is reviewed, the
patient's log is correlated (see photos), and hopefully, the role, if any,
of acid reflux can be determined.
Overnight pH monitoring is also used as a
preoperative assessment prior to reflux surgery, and may be helpful in
evaluating recurrent postoperative symptoms, such as might be seen with the
rare unsuccessful, incomplete, or "unwrapped" reflux repair.
Other than a several hour fast, the only
preparation necessary (and a very important one at that) is avoidance of
acid reducing medications for several days
Recent studies have suggested that shorter
monitoring periods may be almost as effective as the standard 24 hours. In
addition, a recently FDA approved wireless transducer that is attached to
the esophageal wall and sheds spontaneously after the recording is complete may eliminate the use of a transnasal
catheter.
