Esophageal Impedance-pH Study
An esophageal impedance-pH study is a medical test performed to evaluate gastroesophageal reflux disease (GERD) to determine whether surgery is necessary for the condition and whether it will be helpful in providing symptom relief. The 24-hour study is an outpatient procedure in which a tube with sensors is inserted into the esophagus to measure acid and nonacid reflux. The patient wears a device that records pertinent data concerning reflux and episodes during which symptoms occur. Correlation between the two is later analyzed to determine whether the patient's symptoms are the result of GERD.
Preparation for the Study
In order to prepare for this study, patients must discontinue medications to inhibit GERD for at least 7 days prior to testing. Medications to be discontinued include proton pump inhibitors, such as Prilosec® and Prevacid® and H2 blockers, such as Pepcid® and Tagamet®. Over-the-counter antacids, like Rolaids® or Tums® may be taken for symptom relief during this period, but should be avoided during the last day before the examination.
The night before the monitoring begins, patients must not eat or drink anything after midnight, although they are permitted to take necessary medications for other medical conditions. Patients are advised to refrain from smoking the day of the test. Asthmatics are encouraged to bring inhalers with them to the procedure.
The Esophageal Impedance-pH Procedure
During the esophageal impedance-pH procedure, the nostril is numbed with anesthetic gel. Prior to the insertion of the probe, a thin flexible tube is inserted into to the esophagus through the nostril to take measurements in order to ensure proper placement. That tube is subsequently removed and the tube with the impedance-pH probe attached to its end is inserted in its place.
Once the insertion is completed, the tube is secured to the patient's nostril and the patient is fitted with a recording device which will be worn overnight. The procedure takes approximately 30 minutes, after which the patient is free to continue a normal routine. Many patients, however, feel uncomfortable eating and drinking during the 24-hour monitoring period.
After an Esophageal Impedance-pH Study
After 24 hours, patients undergoing an esophageal impedance-pH study return to the medical site to have the monitoring tube and probe carefully removed. The information provided by the data recorder is reviewed and analyzed by the physician and will be discussed with the patient, though it may take up to 2 weeks for the data to be analyzed.
The esophageal impedance-pH study is very safe and it is extremely rare for there to be any serious complications. Patients usually experience some nasal or throat irritation after the tube is removed, but this is quite temporary. Occasionally, a patient may have a nosebleed after the procedure.