An ambulatory 24-hour pH/impedance monitor is a valuable tool for diagnosing gastroesophageal reflux disease.  The impedance probe is a very small catheter (about one-fourth the thickness of a pencil) which is inserted through the nose and into the esophagus.  The probe records changes in the acidity of the esophagus while measuring how frequently stomach acid refluxes into the esophagus.  It also records how long each reflux episode lasts.

Patients are required to fast after midnight the night before the test. They will be here approximately ninety minutes the day that the catheter is placed.  The end of the catheter exits through the nose and is connected to a small computerized box that will be worn for the next 24 hours while the patient continues their normal daily activities.  While the probe is in place, the patient will also keep a diary and will note times when having symptoms, eating, taking medications and sleeping.  The patient will return to the office the next day to return the recording device and have the catheter removed. This visit only lasts a few minutes.  The information recorded is then downloaded and sent to the physician who interprets the information and notes any correlation between  symptoms in the diary and recorded information.