Esophageal manometry is a diagnostic test that measures the function of the muscular tube connecting the throat to the stomach, known as the esophagus. It assesses the motor function, or motility, by measuring the pressure and coordination of muscle contractions. Using a specialized, pressure-sensitive tube, the test determines if the muscles are correctly propelling food and liquid toward the stomach, helping identify the underlying cause of swallowing difficulties.
Symptoms and Conditions Diagnosed
A physician typically orders an esophageal manometry test for patients experiencing symptoms that suggest a problem with the esophagus’s ability to move food. These symptoms include dysphagia (difficulty swallowing) and regurgitation. The test is also commonly utilized when patients report non-cardiac chest pain or chronic heartburn that does not respond to standard medication protocols for gastroesophageal reflux disease (GERD).
The manometry test helps diagnose specific motility disorders by identifying abnormalities in muscle function. Achalasia is one such condition, characterized by the lower esophageal sphincter (LES) failing to relax properly while the muscles of the main esophageal body may be weak. Diffuse esophageal spasm (DES) involves uncoordinated, forceful, and erratic contractions along the length of the esophagus. The test can also reveal the effects of systemic diseases like scleroderma, which can cause the muscles in the lower esophagus to weaken and stop moving altogether, leading to severe reflux.
Preparation and Procedure Steps
Preparation involves several steps to ensure the accuracy of the pressure measurements. Patients are typically instructed to avoid eating or drinking for at least six hours before the test to ensure the esophagus is clear. You may also be asked to temporarily stop taking certain medications that can affect muscle function, such as nitrates, calcium channel blockers, or opioids, usually for 24 to 48 hours prior to the appointment. Residual food or the presence of these medications can interfere with the true reading of muscle activity.
The procedure begins with the patient sitting upright while a nurse applies numbing gel to one nostril and potentially a spray to the throat to minimize discomfort. A thin, flexible catheter, which contains numerous pressure sensors, is then gently guided through the numbed nostril and into the throat. The patient is asked to swallow small sips of water to aid in advancing the catheter down the esophagus until the tip rests inside the stomach. While the tube’s insertion may cause temporary gagging or watery eyes, the process is generally uncomfortable rather than painful.
Once the catheter is positioned, the patient is often asked to lie on their back for the measurement phase. The pressure sensors measure the muscle activity as the patient performs a sequence of approximately ten swallows of a small amount of water. Between each sip, the patient must remain still and not swallow, allowing the device to record baseline pressures and the strength and speed of the contraction wave. The total test typically lasts between 30 and 45 minutes, during which the patient can breathe and talk normally.
Understanding the Pressure Readings
The data is converted into a visual map showing the pressure and timing of muscle contractions throughout the esophagus and its two sphincters. A normal reading shows highly coordinated muscle movement, with a single, progressive wave of contraction, known as peristalsis, moving from the top to the bottom of the organ. The Upper Esophageal Sphincter (UES) and the Lower Esophageal Sphincter (LES) must maintain specific resting pressures and relax completely when a swallow occurs.
Abnormal readings can indicate a variety of motility problems based on the specific pattern of pressure change. In achalasia, the LES often shows an abnormally high resting pressure and fails to relax fully after a swallow, preventing food from entering the stomach. Conversely, weak or absent peristalsis, where the muscle contractions are too feeble or irregular to move contents, may be referred to as ineffective esophageal motility. Highly erratic, forceful, and premature contractions may point toward a spastic disorder, such as the “jackhammer esophagus,” where the muscle force is excessively high.
Potential Risks and Post-Test Care
Esophageal manometry is considered a very safe procedure. The most common experiences following the test are minor and temporary, including a mild sore throat, a stuffy nose, or slight nasal irritation. Occasionally, a minor nosebleed may occur due to the passage of the catheter, but this resolves quickly.
Patients are able to resume their normal diet and activities immediately after the catheter is removed. Medications that were temporarily paused can usually be restarted, though this should be confirmed with the healthcare provider. The pressure data collected during the test will be analyzed by a specialist, and the results will be discussed with the patient at a follow-up appointment.