What is Esophageal Manometry?

Gastroenterologists perform esophageal manometry to determine the strength and function of a patient’s esophagus and esophageal sphincter. It measures pressures and muscle contraction patterns in the patient’s esophagus.

Esophageal manometry is used to evaluate patients who have difficulty swallowing — keeping in mind that there are numerous diseases of the esophagus that cause people to have difficulty swallowing and/or the sensation of having food stuck in their throat.

Esophageal manometry is also used to evaluate patients who have chest pain that is related to their esophagus (i.e., not their heart), people who suffer from heartburn or acid reflux and those who are scheduled to have certain operations.

What roles do the esophagus and sphincter play?

The esophagus is a tubular muscle that works with gravity to push food into the stomach using a highly coordinated series of muscle contractions. The sphincter muscle is situated at the lower end of the esophagus and it remains closed until a person swallows food or liquid.

What is a 24-hour pH Monitoring Impedance test?

Gastroenterologists perform 24-hour pH monitoring and impedance tests to measure how much acid (and non-acid) stomach content is flowing backwards or refluxing into a patient’s esophagus. The doctor uses this information to determine if the patient’s heartburn, chest pain, cough or hoarse voice is related to acid reflux. Gastroenterologists also use this test to investigate why a patient’s symptoms aren’t improving while they are taking acid reflux medicine.

How should patients prepare for these tests?

An empty stomach will result in the safest and most accurate examination, so patients should not eat or drink anything for six hours before they have an esophageal manometry or 24-hour pH monitoring and impedance test.

Because a lot of medications affect the esophageal pressure and muscle contractions that are required for swallowing — especially blood thinners or blood pressure medications (i.e., calcium channel blockers), nitrates and other drugs that affect the gastrointestinal tract such as narcotic pain medicine — patients should let their gastroenterologist know about every medication they are taking before they have one of these tests.

Patients can take acid-lowering medications before they have a 24-hour pH monitoring and impedance test, but they should check with their gastroenterologist first to see if this is appropriate for their test.

What happens during these tests?

Esophageal Manometry

The gastroenterologist or a member of the medical team will use a cream or spray to numb the inside of the patient’s nostrils. A thin, flexible and lubricated catheter (i.e., tube) is then passed through the patient’s nose and into the stomach while he/she swallows sips of water. The patient is seated or lying on his/her back while the catheter is connected to a computer. This test typically requires the patient to swallow liquids 10 times. Once done, the catheter is gently removed. The procedure normally takes about 30 minutes. Some patients experience mild discomfort in their nose and/or throat during the procedure.

In some instances, the gastroenterologist may determine that the best approach is to sedate the patient and pass the catheter through the mouth (versus the nose) using an upper endoscopy, which involves a small camera that’s housed in the tip of a flexible tube.

24-hour pH Monitoring/Impedance

The patient’s nostrils are numbed using a cream or spray to make it easier for the gastroenterologist or a member of the team to pass a catheter through the patient’s nose and into the esophagus as they take sips of water. The tube is then taped to the patient’s nose to ensure that the catheter remains in place. The procedure normally takes 15 to 30 minutes to complete. Once done, the patient is sent home and asked to wear a small data recorder on the belt for the next 24 hours. Patients can eat, drink and sleep as normal during this period, although they will need to keep a diary of their meals and activities and whether they experience any reflux episodes or symptoms. The doctor or a member of the team will remove the catheter, belt and data recorder the following day.

What happens once the catheter is removed?

Once the catheter is removed, the patient may experience a mild sore throat or stuffy nose. While it is rare, some patients have minor nosebleeds. The good news is these conditions typically subside in a few hours and unless the gastroenterologist says otherwise, the patient is free to resume their normal routine, diet and medications as soon as the catheter has been removed. The gastroenterologist will discuss the test results with the patient within a few days.

Do these tests have risks or side effects?

Beyond the mild symptoms that can occur after the catheter is removed, patients who have esophageal manometry or 24-hour pH/impedance tests rarely have serious side effects. Patients can momentarily choke if the tube accidentally shifts into the windpipe or airway. In extremely rare cases, patients may experience aspiration (i.e., when the stomach contents flow back into the esophagus) or have a perforation (i.e., a tear in the esophagus).

The key takeaway is that gastroenterologists always take every precaution and will only recommend patients have an esophageal manometry or 24-hour pH/impedance test if they believe the benefits outweigh the risks.

About the American Society for Gastrointestinal Endoscopy (ASGE)

Since its founding in 1941, the ASGE has been dedicated to advancing patient care and digestive health by promoting excellence and innovation in gastrointestinal (GI) endoscopy. ASGE physicians have highly specialized training in endoscopic procedures of the digestive tract, including upper GI endoscopy, flexible sigmoidoscopy, colonoscopy, endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasound (EUS).

Visit ASGE.org for details on ASGE’s Understanding Esophageal Manometry & 24-Hour pH and Impedance Tests

Important Reminder: This information is intended only to provide general guidance. It does not provide definitive medical advice. It is very important that you consult your doctor about your specific condition.