How is high‑resolution esophageal manometry performed?

How Esophageal Manometry is Performed

High-resolution esophageal manometry (HRM) is performed by passing a multi-sensor catheter transnasally into the esophagus and recording pressure data during standardized water swallows, with the patient typically in a supine position, followed by adjunctive provocative testing in the upright position. 1

Pre-Procedure Preparation

Equipment Setup

• The catheter must be cleaned according to manufacturer guidelines and local protocols before each procedure 1
• Calibration and zeroing must be performed per manufacturer specifications prior to testing 1, 2
• HRM catheters contain up to 36 pressure sensors spaced at 1-cm intervals, allowing simultaneous measurement across the entire esophagus 1

Patient Preparation

• Fasting requirements: Standard 6-hour fast before the procedure 1
• Extended fasting for suspected achalasia: If endoscopy showed retained food/liquids in the esophagus, require a 12-hour fast or even a 2-3 day liquid-only diet 1
• Medication adjustments: Stop medications affecting esophageal motility (nitrates, calcium channel blockers) for 48 hours if possible 1
• Anticoagulation considerations: Patients on warfarin, clopidogrel, or direct oral anticoagulants should be warned about increased nosebleed risk; ensure INR is within therapeutic range (not above) for warfarin patients 1
• Informed consent must be obtained 1

Personnel Requirements

• The operator must be fully trained and accredited by AGIP (Association of Gastrointestinal Physiologists) or supervised by an accredited practitioner 1, 2

Standard Procedure Protocol

Catheter Insertion

• The HRM catheter is passed transnasally and positioned to record from the hypopharynx to the stomach 3, 4
• After insertion, allow a 5-minute resting period to assess basal sphincter pressures 4

Standard Swallow Protocol

• Ten 5-mL room-temperature water swallows are performed as the core assessment 1, 2
• Allow 20-30 seconds between each swallow to ensure complete recovery 1, 2
• Position: Conventionally performed in the supine position, though upright positioning may be used for solid-state (not water-perfused) catheters and is more physiological 1, 2

Adjunctive Provocative Testing

These maneuvers are performed in the upright position (sitting at 90° to horizontal) and are essential because standard water swallows alone miss clinically significant disorders in up to 50% of dysphagic patients 2:

• Rapid Drink Challenge (RDC): Patient drinks 200 mL of water freely through a straw; RDC-IRP >12 mm Hg identifies achalasia-related obstruction 2
• Multiple Rapid Swallows (MRS): Repetitive 2-mL swallows at 1-2 second intervals; highly sensitive for uncovering peristaltic reserve 2
• Solid/Test Meal Swallows: Standardized cooked-rice meal or patient's culprit food; changes manometric classification in ~67% of patients and doubles detection of major motor disorders 2

Data Acquisition and Display

Pressure Topography

• HRM data are converted into dynamic esophageal pressure topography (EPT) plots, also called Clouse spatiotemporal plots 5, 6
• These provide a visually intuitive, color-coded representation of pressure activity across the entire esophagus in real-time 7, 5

Key Measured Parameters

• Integrated Relaxation Pressure (IRP): Lowest mean esophagogastric junction pressure over 4 seconds within a 10-second window after swallow onset 1, 2
• Distal Contractile Integral (DCI): Product of contraction amplitude (mm Hg) × duration (s) × length (cm); DCI >450 confirms intact peristalsis 1, 2
• Distal Latency (DL): Time from upper esophageal sphincter relaxation to contractile deceleration point; DL <4.5 seconds indicates premature/spastic contractions 1, 2

Critical Pitfalls to Avoid

• Do not use incorrect catheter-specific normal values: IRP reference ranges are manufacturer-specific (e.g., Unisensor catheters yield higher values than Manoscan); using wrong values leads to misdiagnosis 2
• Do not rely solely on supine water swallows: This produces false-positive major motor disorder diagnoses; always perform adjunctive testing 2
• Do not skip pre-procedure endoscopy: Patients with dysphagia must undergo endoscopy with biopsies before HRM to rule out mucosal disease (eosinophilic esophagitis) and structural lesions 1, 2
• Position-specific interpretation matters: Supine IRP values average ~4 mm Hg higher than upright, leading to more false-positive outlet obstruction diagnoses (16/20 supine vs 1/4 upright) 2