Home » Procedures » Esophageal Impedance Testing
Esophageal impedance testing is also referred to as esophageal 24-hour impedance reflux monitoring. An esophageal impedance test measures the amount of acidic and non-acidic reflux in your esophagus from your stomach, over a 24-hour time period. This helps your health care provider determine whether or not the reflux of stomach contents is causing heartburn, sore throat, cough or regurgitation.
Esophageal impedance testing is usually performed for patients that are being considered for endoscopic or surgical anti-reflux repair.
It is also used to help diagnose:
In an esophageal impedance test a very thin, single-use, catheter is placed through your nasal passage and then swallowed into your esophagus with drinks of water. The other end of the catheter will run over your ear and attached to a small data recorder. The information gathered is passed onto a computer where it is stored and analyzed. While the test is being performed you will be able to carry out normal bodily functions like swallowing, talking and breathing without difficulty.
Some patients may experience some discomfort in the back of the throat during the esophageal impedance test but a majority of patients rarely feel discomfort and are able to complete the test.
Your gastroenterologist will most likely ask you to stop taking your reflux medication such as Prilosec, Prevacid or Dexilant for up to 7 days before the test. You can take Tums or other antacids up until 6 hours for the test is done. During the test you will be asked to not take any reflux medication or antacids. Otherwise, it is important that you go about your daily routine during the test to get the most accurate results. There will also be additional instructions regarding your medications. In most cases, your medications will be continued as usual. However, in certain circumstances, especially in patients on blood thinners (i.e. coumadin, warfarin, plavix, aspirin, and anti-inflammatories) and in diabetics, special instructions will be given.
What Happens On The Day Of The Test?
You will be asked to arrive at the Endoscopy center 30 minutes before your exam. This is to allow time to fill out paperwork and prepare for the exam.
Once in the procedure room, you will be asked to lie on an exam table. One of the nostrils will be numbed with lidocaine. The nurse will then place a thin catheter into the nostril. As the catheter is advanced into the esophagus, you will be asked to swallow to help open up the esophagus. Once the catheter is in an appropriate position it will be connected to the recorder. Overall, the exam will take approximately 15-30 minutes.
Because there is no sedation for the exam, you will be allowed to leave the endoscopy unit as soon as you are finished. Most patients are able to eat and drink normally after their discharge from the endoscopy unit, however, specific instructions regarding activity, eating, and medications will be given to the patient prior to discharge.
Because the probe measures the pH of the esophagus for 24 hours, you will need to return to the endoscopy unit the following day to have the catheter removed.
Because the computer must generate graphs and tables from the data obtained during the exam, the results of the test will not be available while you still at the endoscopy unit. The test results will be interpreted by the physician at a later time. You should be contacted by the doctor’s office within a week with the exam results.
The esophageal impedance test is a very safe procedure. Complications occur in less than 1% of patients. Most complications are not life-threatening, however, if a complication occurs, it may require hospitalization and surgery. Prior to the exam, a consent form will be reviewed with the patient by the nursing staff.
Perforation or puncture of the esophagus is a very uncommon complication but can occur. This may be recognized at the time of the exam, or it may not be apparent until later in the day. In most cases, a perforation will require surgery and hospitalization.
It is very important that the patient contact the doctor’s office immediately if symptoms arise after the procedure such as worsening abdominal pain, bleeding, or fever.
Like any other test, an esophageal impedance test is not perfect. There is a small, accepted risk that abnormalities can be missed at the time of the exam. It is important to continue to follow-up with your doctors as instructed and inform them of any new or persistent symptoms.
To an extent, the alternatives to the exam will depend on the reason for needing to undergo the 24 hour pH probe in the first place. The only other alternative to measuring the pH of the esophagus is the Bravo 48 hour pH probe.
A Bravo 48 hour pH probe is a procedure whereby a small pH monitor is attached to the bottom part of the esophagus via a thin catheter introduced through the mouth. Once in place, the monitor is detached from the catheter which is then removed. Thereafter the monitor will transmit its data to a wireless recorder worn on the belt for the following 48 hours. Within a few days of completing the procedure, the pH monitor will spontaneously detach from the esophagus and pass out the digestive tract.
The purpose of the study is to look for abnormal amounts of acid within the esophagus. A 48 hour pH probe may be ordered by your physician in order to evaluate for gastroesophageal reflux disease (GERD), help determine the cause of chest pain, or prior to esophageal surgery.Often an esophagogastroduodenoscopy (EGD) is performed to help place the esophageal monitor.
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