Casco Bay Surgery
10 Andover Road
Portland, Maine 04102
*** You must be off of your anti-reflux medication for 7 days prior to testing. ***
Goal of the test
To measure the amount of stomach acid flowing backwards (refluxing) into your esophagus during a 24 or 48-hour period. This will indicate whether you have an abnormal amount of reflux and will help determine whether your symptoms are due to that reflux.
How the test works
The probe detects every time stomach acid enters your esophagus and records the acid level (pH) on a small data-recording box you will carry with you. The recording box has several buttons on it for you to push when you have heartburn or other symptoms, a meal, or during some other events. You will receive instructions before you go home, but ask the nurse before you leave if you aren’t completely clear about how to use the buttons. Once the data collection box is returned (to the Endoscopy Center for tests done at Maine Medical Center), the information is loaded into a computer for analysis, printed and sent to our office. This can take several weeks.
Two techniques are available for this study
1. Bravo 48-hour pH study: The endoscopist will attach a tiny acid-sensing transmitter to the lining of your lower esophagus using sedation and endoscopy. It will transmit data through your body using radio waves. The data recording box must stay within 3 feet of you the entire 48 hour study period, after which it will automatically shut off. Return the box as soon as you can. Maine Medical Center will provide you a mailing envelop if you live far away. This is the most common test and the one we use when we are doing your endoscopy at the same time.
2. Conventional or Impedance 24-hour pH study: The staff in the Endoscopy Center will pass a tiny catheter the size of a piece of cooked spaghetti down one nostril (after numbing your nose with a spray) and will have you swallow it down into your esophagus. It connects directly to the data recording box. You return to the Endoscopy Center the next day to have the catheter removed. We use this approach when insurance companies won’t cover the Bravo study, when it’s more convenient for patients to have the study done closer to home (where the Bravo is not available), and when we need more information than just pH (acid) – an Impedance Study.
Importance of the exam
We use this test only when we believe it is essential for confirming acid reflux as the source of your symptoms and making an appropriate decision regarding the usefulness of antireflux surgery. For that reason, anything that affects the accuracy of the test can cause us to interpret the results incorrectly. These errors can either underestimate or overestimate the degree of reflux. Although it’s not likely we would do unnecessary surgery, we could very well decide against an operation that would be beneficial or curative. Usually we can identify a flawed study and repeat it.
Most common problems
• Chest discomfort or painful swallowing – The Bravo transmitter will detach by itself and pass through your intestine undetected within 5-7 days. Some people will have a dull ache under the breastbone until that happens.
• Stomach isn’t making acid – This occurs when someone doesn’t stop taking their antireflux medication (Prilosec, Prevacid, Aciphex, Protonix, Pepcid, Zantac, Axid, Tagamet) or doesn’t stop taking it long enough before the test. Put bluntly, we want you to have a bad day, with a lot of your usual symptoms. Stop your medication a week or more in advance so that you will have symptoms. Antacids (Mylanta, Maalox, TUMS, Rolaids, Gaviscon) are okay to take up until the night before the test because they are very short-acting. If going a week without medication is truly miserable even with antacids then you may stop your medication at whatever point ahead of the test will result in you having symptoms on the day of the test. Medication use is the most common reason for me to cancel a test at the last moment. If you are feeling fine the morning of your exam, call the office so we can consider rescheduling it for another day.
• Inaccurate symptom recording – Our ability to tell whether your symptoms are due to reflux is only as accurate as your recording of those symptoms either with the buttons on the recording box or in a written diary (or, ideally, both). If you don’t record the occurrences and timing of your symptoms very well, we’re more likely to make an incorrect interpretation that your symptoms aren’t due to reflux. That might keep us from recommending surgery or at least delay you in getting what could be useful and curative surgery.
• System malfunction – Occasionally the test simply fails, but not often. The most common thing to go wrong is for the implantable Bravo probe to detach and pass through your stomach and into your intestine before it has a chance to collect useful information. The less frequently used down-the-nose probes can also shift positions or fall out altogether. If something goes wrong early in the study, we sometimes have no choice but to ask you to repeat on another day.
Don’t leave the Endoscopy Center if you have any questions about what you’re supposed to do during the test. If you have any questions or problems, please don’t hesitate to call us, either before or during the 24-48 hour test period (207-761-6642).
Last updated 7/11/13 rc