Enter the IRP value and select the catheter type to visualize the GOJ relaxation profile.
Guidelines & Evidence
Clinical Details
Section 1
When to Use
When to Use
Defining Esophagogastric Junction (EGJ) obstruction in High-Resolution Manometry (HRM)
The primary diagnostic threshold for all types of Achalasia (v4.0 Chicago Classification)
Distinguishing between functional obstruction (high IRP) and normal motility (normal IRP)
The 'Integrated' Logic
The IRP represents the lowest average pressure of EGJ relaxation over 4 seconds (continuous or non-continuous) during the 10-second window following a swallow.
Section 2
Formula & Logic
Hardware-Specific Thresholds
Medtronic (Given)
Abnormal if > 15 mmHg
Diversatek (Sandhill)
Abnormal if > 22 mmHg
Unisensor
Abnormal if > 19 mmHg
Interpretation Protocol (v4.0)
01
Step 1: Check IRP in the supine position (10 swallows).
02
Step 2: If equivocal (e.g., 10–15 mmHg), check upright IRP.
03
Step 3: If still equivocal, perform a Rapid Drink Challenge (RDC) or Multiple Rapid Swallows (MRS) to "stress" the EGJ.
Section 3
Pearls/Pitfalls
Achalasia with a "Normal" IRP
Up to 5% of patients with clinically proven Achalasia may have a "Normal" IRP (e.g., 12 mmHg) on a single study. This is why the Chicago v4.0 criteria allow for a diagnosis of Achalasia even with a borderline IRP if there is 100% failed peristalsis AND evidence of obstruction on Timed Barium Swallow.
The Artifact Trap
Diaphragmatic "crural" interference can falsely elevate the IRP. Clinicians should ensure the IRP box on the manometry software is correctly positioned over the LES and away from the crural diaphragm to avoid over-diagnosis of EGJOO.
Clinical Pearls
A high IRP in a patient with persistent peristalsis is the definition of EGJ Outflow Obstruction (EGJOO)
The IRP should always decrease (improve) following successful POEM or Heller Myotomy
Hiatal hernia can cause "pseudo-high" IRP due to overlap of the hernia sac and the LES
In the era of conventional manometry, we measured "Resting LES Pressure." Peter Kahrilas and his team recognized that the "residue" of pressure during relaxation (IRP) was a far more powerful predictor of bolus transit failure than the baseline resting tone.
