What is an esophageal pH test?
PH is a measure of acidity. An esophageal pH test measures and records the pH in your esophagus. The esophagus tolerates acid poorly and is exposed to acid rarely throughout the day. The main use of esophageal pH is to determine if you have gastroesophageal reflux disease (GERD). The test can also be done to determine the effectiveness of medications or surgical treatment for GERD.
When you swallow, a valve called the lower esophageal sphincter (LES) controls the passage of food from the esophagus to the stomach when you swallow. It remains tightly closed except when you swallow food. When this muscle fails to close or opens spontaneously, acid, bile and food contents of the stomach can travel backward into the esophagus. The esophageal pH test measures how often stomach contents reflux into the lower esophagus and how much acid the reflux contains.
How does the esophageal pH test work?
A thin, small tube with an acid-sensing device on the tip is gently passed through your nose, down the esophagus, and positioned about 2 inches above the lower esophageal sphincter. The tube is secured to the side of your face with clear tape. The end of the tube exiting from your nose is attached to a portable recorder that is worn on your belt or over your shoulder. The recorder has several buttons on it that you will press to mark certain events. A nurse will review the monitoring instructions with you.
The pH probe send a signal to the recorder (about the size of a pager) worn on your belt or waistband. The recorder has several buttons on it that you will press to record symptoms of GERD, such as heartburn. The nurse will tell you what symptoms to record. You will be asked to maintain a diary to record certain events such as when you start and stop eating and drinking, when you lay down, and when you get back up. This will be explained by the nurse.
A wireless pH monitoring system, Bravo Probe, allows the pH probe to be placed without the need for a direct connection to the recording device. This is more comfortable and can provide a longer recording of esophageal pH.
How do I prepare for the esophageal pH test? Medication Guidelines
- 7 days before the monitoring period, do not take proton pump inhibitors: omeprazole (Prilosec), lansoprazole (Prevacid), rabeprazole (Aciphex), pantoprazole (Protonix), esomeprazole (Nexium).
- 2 days (48 hours) before the monitoring period, do not take the H2 blockers: ranitidine (Zantac), cimetidine (Tagamet), famotidine (Pepcid), nizatidine (Axid); or the promotility drug metoclopramide (Reglan)
- 6 hours before the monitoring period, do not take antacids (such as Alka-Seltzer, Gaviscon, Maalox, Milk of Magnesia, Mylanta, Phillips, Riopan, Tums, or any other brands).
- 4 to 6 hours before your appointment do not eat or drink.
Please note: Occasionally, your doctor might want you to continue taking a certain medicine during the monitoring period to determine if it is effective.
Once the test has begun, what do I need to know and do?
- Activity — Follow your usual daily routine. Do not reduce or change your activities during the monitoring period. Doing so can make the monitoring results less useful.
- Bathing – Do not take a tub bath or shower during the monitoring period; the equipment cannot get wet.
- Eating —Eat your regular meals at the usual times. If you do not eat during the monitoring period, your stomach will not produce acid as usual, and the test results may not be accurate. Eat at least two meals a day. Eat foods that tend to increase your symptoms (without making yourself miserable). Avoid snacking. Do not suck on hard candy or lozenges, and do not chew gum during the monitoring period.
- Lying down — Remain upright throughout the day. Do not lie down until you go to bed (unless napping or lying down during the day are part of your daily routine).
- Medicines — Continue to follow your doctor’s advice regarding medicines to avoid during the monitoring period.
- Recording symptoms — Press the appropriate button on the recorder when symptoms occur (as discussed with the nurse).
- Recording events – Record the time you start and stop eating and drinking (anything other than plain water). Record the time you lie down (even if just resting) and when you get back up. The nurse will explain how to record this information.
- Unusual symptoms or side effects — If you think you might be experiencing any unusual symptoms or side effects, call your doctor.
You will return the next day to have the tube removed. The information on the recorder will be downloaded to a computer. The results as well your diary will be reviewed and analyzed.
Bravo probes are usually used for two days, after which the recorder is returned. The probe passes silently through the GI track and is not recovered.
After the test is completed
- Resume your normal diet and medications.
- Lozenges or hard candy may help relieve any temporary discomfort or a sore throat after the test.
Your doctor will discuss the results of the test with you during your next scheduled appointment.
