Esophageal manometry is a specialized diagnostic test that evaluates the motor function of the esophagus, the muscular tube connecting the throat to the stomach. The procedure precisely measures the pressure and coordinated movement, known as peristalsis, within this organ. Utilizing a catheter equipped with numerous pressure sensors, the test records how the esophageal muscles and the two surrounding valves function during swallowing. This assessment provides objective data about the strength, speed, and pattern of muscle contractions, which is crucial for diagnosing disorders that cause symptoms like difficulty swallowing or noncardiac chest pain.
Conditions Diagnosed by Manometry
Esophageal manometry primarily identifies specific disorders of esophageal motility, often causing chronic, unexplained symptoms. The test is the definitive method for diagnosing achalasia, a disorder where the lower esophageal sphincter (LES) fails to relax properly, and the esophagus loses its ability to contract effectively. Manometry distinguishes achalasia into three subtypes, which helps guide the most effective treatment plan.
The procedure also identifies spastic disorders, involving abnormal, uncoordinated, or overly forceful contractions. These include Distal Esophageal Spasm, characterized by premature contractions that interfere with normal food movement. Hypercontractile Esophagus, or “jackhammer esophagus,” is identified by excessively strong muscle contractions. Accurate manometric measurement of these patterns is necessary because the symptoms of various motility disorders often overlap. Furthermore, manometry is performed prior to anti-reflux surgery to ensure the esophagus has adequate function, ruling out underlying motility issues that could lead to complications.
Preparing for Esophageal Manometry
Specific preparation ensures the esophagus is clear and test results are accurate. Patients are required to fast, avoiding all solid food for at least six to twelve hours before the procedure. This ensures the stomach and esophagus are empty, preventing food residue from interfering with catheter placement or pressure readings. Clear liquids, such as water, apple juice, or black coffee, may be allowed up to two or three hours before the scheduled test time.
Medication Adjustments
It is necessary to temporarily discontinue certain medications that affect muscle function or pressure readings. Drugs like nitrates, calcium channel blockers, and opioids must often be stopped 24 to 48 hours prior to the test. Promotility agents, which stimulate muscle movement, are also typically paused for a few days before the manometry. Patients must review their complete medication list with their healthcare provider beforehand to receive personalized instructions on which drugs to hold and when.
The Step-by-Step Procedure
The manometry procedure usually takes approximately 30 to 45 minutes and is performed while the patient is awake, since sedation would interfere with natural swallowing mechanics. The process begins with applying a numbing gel or spray to one nostril and the back of the throat to minimize discomfort during insertion. A trained technician then gently guides a thin, flexible catheter, containing multiple high-resolution pressure sensors, through the numbed nostril.
The patient is asked to swallow small sips of water as the catheter is advanced past the pharynx and down the esophagus until the tip sits within the stomach. Once positioned, the patient is asked to lie down for the primary testing phase. The patient is instructed to perform a series of ten wet swallows, typically using about five milliliters of water for each, with a mandatory 30-second pause between swallows to allow the esophagus to return to a resting state. The pressure sensors transmit real-time data to a computer, creating a topographical map that visualizes the muscle activity.
Understanding Manometry Results
The data collected is analyzed using standardized metrics to assess esophageal muscle function. The High-Resolution Manometry system is the current standard, and results are interpreted using the Chicago Classification, a systematic framework for categorizing motility disorders. Key measurements include the Integrated Relaxation Pressure (IRP), which quantifies how effectively the Lower Esophageal Sphincter (LES) relaxes to allow food passage into the stomach. An elevated IRP is the defining feature of achalasia or other forms of outflow obstruction.
The strength and coordination of peristaltic contractions in the main body of the esophagus are measured using the Distal Contractile Integral (DCI). This metric combines the amplitude, duration, and length of the contraction wave to provide a single value representing the force of the swallow. Low DCI values are associated with ineffective peristalsis, while excessively high DCI values, typically above 8,000 mmHg·cm·s, indicate a hypercontractile esophagus. Clinicians analyze these metrics, along with the timing of the contraction wave, known as Distal Latency, to establish a precise diagnosis and determine the appropriate therapeutic approach.