Your physician may ask you to have 24 hour Ambulatory Monitoring (testing).

If you have symptoms of heartburn or acid reflux, your physician may want to determine the amount of acid (the pH) that is getting into your esophagus from your stomach and/or the amount of bile getting into your esophagus from your stomach.

If you have dysphagia (trouble swallowing or food getting stuck when you eat) your physician may ask you to have continuous monitoring of the contractions of your esophagus.

These tests are called ambulatory monitoring because you go home and go about your usual daily routine while you're being monitored.

Again, a small (2mm) catheter is inserted through your nose, down the back of your throat and into your esophagus. The tube is taped in place on your nose and has a long cord that is attached to a portable data recorder (about the size of a Walkman). You wear the recorder in a pouch that has a strap that goes around your shoulder.

If you're having the amount of bile measured too, you will have two machines (the second one you wear around your waist).

You will be given specific instructions about your activity and what to eat during the test. Please wear a shirt or blouse that buttons up the front, this will make changing your clothes easier during the study. You will also have the name and phone number of the nurse to call should you experience difficulty during the test.

Again, the complications of this procedure are exceedingly rare, with the most significant being esophageal perforation. Sometimes your nose might bleed and you may have a sore throat after the test.

If you have questions regarding whether you need to have these tests, you should call the physician who requested that you have the testing. He or she will be able to answer your questions.