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HRM theory

In this instruction we will explain the concept of HRM, short for High Resolution Manometry.

HRM has its roots in conventional manometry.

Conventional manometry uses 4 to 8 pressure channels to record esophageal peristalsis.

More pressure sensors and contour plots led to High Resolution Manometry.

During the past decades manometry techniques have been improved.

In the nineties the late Ray Clouse visited MMS.

Together we developed the new HRM system.

His concept was to use more sensors which are closely spaced on the catheter.

He came up with a different idea to display the data.

Data is displayed like a topographical surface map.

Altitudes are represented by colors.

The sea has a low altitude and is blue.

Mountains have warm colors like red or purple.

The altitude colors are also used to display the pressure levels.

This concept is called the Clouse contour plot and is easier to read.

Let's look at a pressure recording from one sensor.

Replacing every pressure level with a different color creates a colored bar.

The colored bars from every sensor are combined by interpolation.

Interpolation results in a contour plot.

This is similar to the altitude colors as explained before.

The contour plot shows a lot of information.

For example you can see landmarks.

Here you see the landmark of the Upper Esophageal Sphincter, the UES.

After swallowing, the contraction of the esophagus appears moving in distal direction.

The landmark below is the Lower Esophageal Sphincter, the LES

One of the benefits of HRM is the clear appearance of the landmarks on the screen.

This enables accurate positioning of the catheter in a fast and easy way.

The complete examination can be done in less than 10 minutes.

In addition to HRM, impedance data can also be recorded.

HRIM, short for High Resolution Impedance Manometry, measures the actual bolus movement.

For the interpretation of HRM studies a new classification scheme has been developed.

The so called Chicago Classification uses new metrics for every individual swallow.

For example IRP, DCI, Distal Latency and more.

The analysis software from MMS follows this classification.

You can easily recognize motility disorders in the contour plot by using the MMS HRM system. For example,

a normal pattern,

weak peristalsis with a large break,

Hiatus hernia,


To perform HRM you need an MMS HRM system with catheters.

A variety of catheters are available:

water perfused and solid state catheters,

catheters with or without impedance rings,

single use or multi use catheters,

catheters with a smaller diameter for pediatric practice.

You can use the HRM technique for measurement in different parts of the body.

the esophagus,

the small bowel,

colon and

the anal sphincter.

To summarize, High Resolution Manometry has significant advances

in the understanding of esophageal peristalsis and other functions.

With HRM you can simplify and shorten the esophageal manometry procedure.

The Description of Gastroenterology: MMS Solar GI HRM