Esophageal pH monitoring is used to diagnose gastro-esophageal reflux (GERD) and to determine the effectiveness of medications that are given to prevent acid reflux. This test measures the amount of acid which is refluxing or backing up from the stomach into the esophagus (food pipe). In order to determine the correct placement of the pH probe, it may be necessary to perform another short test called an esophageal manometry (see additional instructions for this esophageal manometry test).
PREPARATION FOR THE TEST:
· Unless requested by your physician, please STOP MEDICATIONS USED FOR TREATING REFLUX AND FOR TREATING STOMACH ACID PROBLEMS.
Some medications should be stopped for 1 week prior to the test. These include Prilosec (omeprazole), Nexium (esomeprazole), Aciphex (rabeprazole), Prevacid (lansoprazole), Protonix (pantoprazole).
Some medications need to be stopped for 2 days before the test. Examples of these medicines are: Zantac, Tagamet, Axid, Pepcid, Carafate.
Note that your physician will want you to continue these medications to determine how effective they are in treating reflux. If so, please take these at your regular time the day prior to the test and the morning of the test (with a little bit of water).
· If you have questions about other medications, talk with your physician.
· DO NOT EAT OR DRINK AFTER MIDNIGHT the night before the test.
· Wear a shirt or blouse which opens in the front so that it is easier to dress after the probe is positioned.
The nose is numbed for a short time. A thin plastic catheter a sixteenth of an inch in diameter is passed into one nostril, down the back of the throat, and into the esophagus as the patient swallows. The tip of the catheter contains a sensor that senses acid. The sensor is positioned in the esophagus so that it is just above the lower esophageal sphincter, a specialized area of esophageal muscle that lies at the junction of the esophagus and stomach and prevents acid from refluxing back up into the esophagus. Placing the probe takes approximately 15 minutes. No sedation is necessary. The catheter protruding from the nose is connected to a recorder that registers each reflux of acid. The patient is sent home with the catheter and recorder in place. During the 24 hours that the catheter is in place, the patient goes about his or her usual activities, for example, eating, sleeping, and working. Meals, periods of sleep, and symptoms are recorded by the patient in a diary and by pushing buttons on the recorder. The diary helps the doctor to interpret the results. The patient returns the next morning for removal of the catheter. After the catheter is removed, the recorder is attached to a computer so that the data it has gathered can be downloaded into the computer where it is analyzed.
What are the side effects of esophageal pH monitoring?
There are very few side effects of esophageal pH monitoring. Although there may be mild discomfort in the back of the throat while the catheter is in place, particularly during swallows, the vast majority of patients have no difficulty eating, sleeping, or going about their daily activities. Most patients, however, prefer not to go to work because they feel self-conscious about the catheter protruding from their nose.
Are there alternatives to esophageal pH monitoring?
The most recently-developed device for monitoring esophageal pH is called Bravo pH monitoring which uses a capsule which contains an acid sensing probe, a battery, and a transmitter. The probe monitors the acid in the esophagus and transmits the information to a recorder that is worn by the patient on a belt. After an upper endoscopy, the capsule is introduced into the esophagus on a catheter through the nose or mouth and is attached to the lining of the esophagus with a clip. The catheter then is detached from the capsule and removed. Thus, there is no catheter protruding from the nose for the recording. The capsule transmits for two days, and then the battery dies. Five to seven days later, the capsule falls off and is passed in the stool. (The capsule is not reusable.) The advantages of the capsule device are related to the absence of a catheter connecting the probe to the recorder. There is greater comfort without a catheter in the back of the throat, and patients are more likely to go to work and do more normal activities without feeling self-conscious about the appearance of the catheter to others. The disadvantages of the capsule are that it cannot be used in the pharynx (where it would be impossibly uncomfortable) and, so far, it has not been used in the stomach. More experience will be necessary to know if the information obtained with the capsule is comparable to the more standard catheter probe.
The capsule device often causes discomfort when swallowing. The discomfort is felt in the chest and may be due to food tugging on the capsule as it passes, although discomfort occasionally can be felt when swallowing only saliva.
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