To prepare for 24 hour PH Impedance study, do not eat or drink for 6 hours before the test. You may need to stop medications that block stomach acid. The advantage of the 24 hour PH impedance test over other tests is that it can measure both acid reflux as well as non-acid reflux. It can also show whether your symptoms are due to reflux or not.
What is a 24 hour PH Impedance?
24 hour PH Impedance is a test to measure acid reflux and non acid reflux. A flexible tube (catheter) is passed through your nostril into the esophagus. You may be asked to swallow or drink water to help with the passage. The outer end of the catheter is taped to your cheek and wrapped over your ear. The end is then attached to a small portable recorder.
The stomach produces acid but the esophagus does not. The esophagus does not tolerate significant acid exposure. Acid in the esophagus leads to heartburn, non-cardiac chest pain, cough, hoarse voice, Barrett’s esophagus and esophageal cancer.
Before the test, you will be given a diary. During the test, you will record your symptoms and activities such as eating, sleeping, lying down.
Who should not do the 24 hour PH Impedance
- Patients with severe inflammation or blockage in the esophagus.
- Those with esophageal varices.
- Patients with severe bleeding disorders.
- People that cannot follow instructions.
- Patients with recent nose surgery. Let the nurse or technician know if you had a broken nose, surgeries on your nose or a deviated septum.
What are the risks of 24 hour PH Impedance
You may experience some gagging during the procedure especially during the passage of the tube. Once the tube is in place, you can actually breathe and talk normally. If the tube goes down the wrong pipe, you may experience choking feeling. The tube is quickly removed when this happens.
Some people experience nose irritation, nose bleeds and sinus problems after the test. Most of these adverse reactions are temporary.
How long does the study lasts
It takes about 10 minutes to put the catheter in the nose. You need to keep the catheter in your nose for 24 hours.
How do I prepare for 24 hour PH Impedance
The test can be done on therapy or off therapy. On therapy means that you will continue to use your acid blocking medications such as prilosec, protonix, prevacid, nexium and dexilant. Off therapy means the test will be done when you are off acid blocking medications. On therapy test is used to assess whether you still have acid reflux despite treatment. Off therapy test is used to confirm if you have acid reflux to begin with.
How to prepare for off therapy 24 hour PH Impedance
Stop 1 week prior to test
Proton pump inhibitors. These are Dexilant (dexlansoprazole), Prilosec (omeprazole), Prevacid (lansoprazole), Nexium (esomeprazole), Aciphex (rabeprazole), Protonix (pantoprazole).
Stop 72 hours prior to test
Histamine 2 receptor antagonists (H2RA). These are Tagamet (cimetidine), Zantac (ranitidine), Pepcid (famotidine), Axid (nizatidine).
Stop 24 hours prior to test
Antacids. These are Gaviscon, Maalox, Mylanta, Tums, Gelusil, Rolaids, Alternagel, Amphogel, Alka-Seltzer, Milk of magnesia, Pepto-Bismol.
What to expect during the procedure
The nurse or technician will confirm your name and procedure. A flexible tube (catheter) is passed through your nostril into the esophagus. You may be asked to swallow or drink water to help with the passage. The outer end of the catheter is taped to your cheek and wrapped over your ear. The end is then attached to a small portable recorder. The recorder is secured to your body by a shoulder strap. It takes only 5-10 minutes to place the catheter. You can eat, drink, talk, and breathe during the test without any problem.
What to expect after the procedure
While the catheter is in place, you can continue your regular activities including eating, sleeping, and talking. You can record meals, sleep, and symptoms in a diary and also by pushing buttons on the recorder. The diary helps your doctor to interpret the results.
The next day (after 24 hours), you will return to the GI office or lab to have the catheter removed. In addition, you will return the recorder. After you return the recorder, the data is downloaded to a computer.
The result should be available to you after your doctor has reviewed and interpreted the result.