Esophageal manometry is a non-surgical diagnostic test used to measure the strength, pattern, and coordination of muscle activity within the esophagus, the muscular tube connecting the throat to the stomach. The procedure assesses esophageal motility to determine how effectively food and liquids move down the swallowing tube. This information is particularly valuable when patients experience difficulty swallowing, chest pain not related to the heart, or symptoms of persistent acid reflux. By accurately mapping the pressures generated during swallowing, the test provides a detailed picture of the esophagus’s ability to contract and the valves’ ability to open and close.
How Esophageal Manometry Works
The fundamental purpose of this test is to analyze the complex muscle movements that push swallowed material toward the stomach. This wave-like muscular contraction is known as peristalsis, and manometry measures the pressure this action creates along the entire length of the esophagus. The test also focuses on two muscular rings, or valves, that control the movement of material in and out of the tube: the Upper Esophageal Sphincter (UES) and the Lower Esophageal Sphincter (LES).
The manometry catheter is a thin, flexible tube equipped with multiple pressure sensors. As the patient swallows, these sensors record the exact pressure changes in real-time, capturing the strength, speed, and timing of the muscle contractions. A computer converts these raw pressure readings into a visual map, allowing specialists to see if the peristaltic wave is coordinated and strong enough to move food efficiently. The data also reveals whether the UES and the LES relax and contract properly during the swallowing sequence.
Preparation Before the Test
Preparing for the manometry test involves specific steps to ensure the esophageal muscles are in a resting state and the measurements are accurate. Patients are typically required to fast, meaning they must avoid all food and drink for a period of six to twelve hours before the procedure. This ensures the esophagus is empty of any material that could interfere with the catheter or the pressure measurements.
Adjustments to a patient’s regular medication schedule are also necessary, especially for drugs that can affect muscle function or motility. Medications like calcium channel blockers, nitrates, and promotility agents must often be stopped days before the test, as they can relax the esophageal muscles and mask underlying problems. Regular heart or blood pressure medications can usually be taken with a small sip of water, but all other non-essential medications should be avoided until the test is complete. Patients should always consult their physician for personalized instructions, particularly regarding insulin or other diabetes medications.
The Esophageal Manometry Procedure
The manometry procedure is performed in an outpatient setting and generally takes between 30 and 45 minutes. Upon arrival, the clinician prepares the patient by applying a topical numbing gel to one nostril and potentially a numbing spray to the back of the throat. This localized anesthetic helps minimize discomfort as the catheter is inserted.
The patient is usually seated upright as the thin, pressure-sensing catheter is gently guided through the numbed nostril. Once the tube reaches the back of the throat, the patient is asked to swallow small sips of water to help the catheter pass smoothly into the esophagus. There may be a brief moment of gagging or watering eyes as the catheter passes this sensitive area, but the sensation quickly subsides once the tube is in place.
Once the catheter is positioned, with its tip extending into the stomach, the patient is asked to either remain seated or lie down on their back. The core of the test involves measuring the esophageal response to swallowing small amounts of water, often referred to as “wet swallows.” The technician instructs the patient to swallow a specific volume, typically 5 milliliters of water, at set intervals, usually ten times.
The computer records the pressure, speed, and pattern of the esophageal contractions as each sip of water moves through the tube. Between swallows, the patient is asked to avoid swallowing to obtain baseline measurements of the resting pressures in the sphincters and the esophageal body. After the necessary data is collected, the technician gently removes the catheter, and the patient can immediately resume normal activities.
Disorders Diagnosed Using Manometry
The detailed pressure data collected by the manometry test is used to diagnose specific motor disorders of the esophagus. One significant condition identified is Achalasia, where the LES fails to relax properly during swallowing, and the esophagus’s body loses its ability to contract effectively. This results in a functional obstruction where food cannot pass into the stomach easily.
Another disorder, Diffuse Esophageal Spasm, is characterized by uncoordinated, forceful, and non-propulsive contractions of the esophageal muscle. Manometry can also detect Hypomotility or Ineffective Esophageal Motility, where the muscle contractions are too weak or absent to efficiently move the swallowed material. The test is routinely performed as a pre-surgical evaluation for patients with severe Gastroesophageal Reflux Disease (GERD). Measuring LES pressure and contraction quality helps ensure the patient does not have an underlying motility disorder, such as Achalasia, which would affect the type of anti-reflux surgery performed.