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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_1033_Библиотеки_им_академика_М_И_Перельмана
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How Does HRM Work?
The combination of two fundamental developments revolutionized the diagnostic evaluation of esophageal motor function. The
rst one was the ability to measure pressures from the pharynx to
the stomach simultaneously with a newly designed catheter. This
was feasible due to the incorporation of multiple closely spaced
pressure sensors within the catheter. Specically, the catheter is a
solid-state catheter 4mm in diameter that contains 36 circumferential sensors, spaced 1cm apart, covering a length of 35cm. This
enables simultaneous recording from all segments (UES to LES),
without the need to reposition the catheter during the study
(Fig.11.1). This makes the procedure faster and more tolerable
for patients.
Sensors are spaced at 1-cm intervals from center to center. This
gives the catheter a recording segment of 35cm. Each individual
sensor (magnied at center) detects pressure from 12 loci (arrow)
around its circumference. Computer processing of the signals
coming from pressure sensing elements allows average
Fig. 11.1 High-resolution manometry catheter. The high-resolution manometry catheter pictured here is 4.2mm in diameter and consists of 36 circumferential, solid-state, pressure sensors (copper-colored bands, arrowhead)
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circumferential pressures over the entire 35-cm recording segment to be displayed in real time and recorded for subsequent
analysis.
The second development was the computer software that
allowed the conversion of the data acquired by HRM into a
topographic (color contour) plot. The software analyzes the
manometric pressures and provides color contours to illustrate
the intraluminal pressures. Time and pressure contour lines
are applied to the tracings with isobaric pressure lines at
5-mmHg intervals. Colors are assigned to pressures; therefore, cooler colors represent lower pressures, and warmer colors represent higher pressures [3]. The contour mode display
is 2-dimensional in which the distance from the nose is on the
y-axis, time is on the x-axis, and the pressure is presented by
color (z-axis). (Fig.11.2).
Fig. 11.2 Comparing conventional recordings of manometric pressure (a)
with the Clouse plot or esophageal pressure topography EPT (b) In the latter,
pressure in the swallowed bolus (intrabolus pressure) is represented by a
small simultaneous rise in intraesophageal pressure seen as a simultaneous
change to a lighter blue color (arrowhead). Notice that when the peristaltic
wave passes, the color becomes a darker blue indicating bolus clearance. TZ,
transition zone. (Copyright 2013 Korean Society of Neurogastroenterology
and Motility)
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How toPerform High-Resolution Esophageal
Manometry?
The adequate diagnosis of esophageal motility disorders requires
high-quality HRM studies. Understandably, the motility laboratory requires not only dedicated personnel (physicians, nurses, or
technicians) but also adequate HRM equipment (catheters, acquisition software, and analysis software) [7]. Today, there are several companies in the market that offer HRM equipment. Yet, it is
worth mentioning that the ManoScan™ ESO catheter (Medtronic
Plc, Dublin, Ireland) was the catheter used for all the research
studies performed for the development of the Chicago
Classication. For that reason, if manometry is performed with a
catheter other than the ManoScan™, the interpretation of the
study should be based on normal values generated for those HRM
systems [8].
Before performing the study, patients should be instructed to
fast for at least 6h for solids and 2h for liquids prior to the procedure. In patients with obstructive symptoms and suspected achalasia, fasting times should be extended as per laboratory policies.
Medications that affect esophageal motility should also be stopped
for at least 3days in preparation for the study. Some of these medications include calcium channel blockers, nitrates, prokinetics,
loperamide, β-blockers, opioids, and anticholinergic agents.
Patients should be given a detailed explanation of the procedure
and informed consent should be obtained.
The motility catheter with 36 circumferential sensors is
inserted transnasally after the application of topical anesthesia.
The catheter is positioned so that at least two distal sensors are in
the stomach and two proximal sensors are located above the UES.
A 5-min acclimation period should be provided to the patient
before starting the study. As an alternative for patients with known
strictures or large hiatal hernias, the catheter can be placed endoscopically after routine calibration. The laboratory technician can
perform the study after the patient recovers from anesthesia. The
correct catheter placement is of key importance for the performance of a high-quality study and can be conrmed by identify-
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ing the pressure inversion point (PIP; negative intrathoracic
pressure associated with inspiration inverts to positive intraabdominal pressure) by asking the patient to take several deep
breaths. After the correct placement of the catheter is conrmed
and the patient is acclimated to the catheter, the study begins.
Figure11.3 demonstrates the HRM of the esophagus at rest and
the software tool that aids in identifying the diaphragm (PIP). It is
important to mention that the PIP is not present in studies in which
the catheter does not cross the EGJ and indicates a technically
inadequate study.
The standard protocol that was used for the development of the
Chicago Classication entails a 30-s swallow-free recording to
obtain the resting pressures of the UES and EGJ (esophagogastric
junction). This period is followed by 10 consecutive swallows of
a 5-ml bolus in the supine position for patients without prior surgery affecting the esophagus or the EGJ [6]. Patients should be
instructed to swallow only once per wet swallow, and swallows
should be about 20–30s apart. This allows for the LES pressure
to return to its resting state and to prevent the deglutitive inhibition from hindering the motility of the esophagus. Figure 11.4
demonstrates a swallow.
The HRM can also be performed in the upright position; however, it should be recognized that pressures are lower in the upright
position compared to supine and normal values are available for
both situations [9]. Additionally, several motility experts have
described the use of apple sauce, solid boluses, or multiple water
swallows to challenge the esophagus and uncover motility disorders that otherwise would not be uncovered by the swallows of
5ml of water [3].
M. R. Youssef et al.
How Is theStudy Interpreted?
The manometry software provides an automated computergenerated analysis of the study; however, the computerized analysis is imperfect and unable to recognize areas where artifact could
be distinguished from true peristaltic contractions. For that reason, an experienced clinician must review each swallow and
a
b
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Fig. 11.3 High-resolution manometry of the esophagus at rest. (a) Demon-
strates a typical recording of the esophagus at rest. The sensor at 17cm from
the nares is in the pharynx, the sensor at 19cm is in the upper esophageal
sphincter (UES), and the sensor at 24cm is in the LES.Those at 27, 32, and
37cm are in the esophagus, and the one at 45cm is intragastric. (b) Inspiration is indicated by I and expiration by E
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Fig. 11.4 Esophageal pressure topography [Clouse plot] illustrating a normal peristaltic contraction and key landmarks used in the Chicago Classication of esophageal motility. P is the proximal pressure trough separating the
proximal and distal contractile segments; D is the trough separating the distal
esophagus from the esophagogastric junction
M. R. Youssef et al.
provide a nal interpretation since an inadequate diagnosis can
adversely affect patient outcomes.
There are three main steps that make up the diagnostic algorithm of an esophageal HRM study:
Step 1: Assess theEGJ Anatomy andFunction
• Main EGJ metrics (EGJ morphology, LES pressure, separation
from the crural diaphragm and the LES)
This is a decisive step because disorders are separated at this
point, determined by those with or without outow obstruction at
the EGJ.This portion begins with the evaluation of the LES rest-
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Fig. 11.5 Traditional and high-resolution manometry: comparison of the 2
esophageal manometry systems currently available. Traditional low-resolution manometry (left; 1960-present) is 5 line tracings derived from pressure
sites located in the LES and 5, 10, 15, and 20 cm above the LES in the esophagus. In contrast, HRM (2007-present) is a color-based topographic plot
extending from pharynx to stomach derived from sophisticated computer
algorithms converting data from 36 pressure sites 1 cm apart into a topograph
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ing pressures during the swallow-free period, the morphology of
the EGJ (LES and diaphragmatic crura), and the presence or
absence of a hiatal hernia. The morphology of the EGJ is classied into three types according to the level of separation that exists
between the location of the LES and the PIP (which indicates the
location of the crural diaphragm) (Fig.11.5) [3, 4].
Type I: the LES and the crural diaphragm coincide.
Type II: small spatial separation of less than 2cm between the
crural diaphragm and the LES.
Type III: large spatial separation of more than 2cm between
the crural diaphragm and the LES.
Next, the LES pressure is assessed, as well as whether the EGJ
is appropriately relaxed with swallowing. Even though the CC
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does not take into account the LES pressure, its assessment is recommended as an average of inspiratory and expiratory values for
three normal respiratory cycles during a swallow-free period. The
EGJ function during swallowing is determined by a measurement
called the 4-s integrated relaxation pressure (IRP). The integrated
relaxation pressure (IRP) measures the relaxation of the EGJ.It is
expressed as a median of the ten test swallows in mm Hg with
15mm Hg being the upper limit of normal (Fig.11.6).
Fig. 11.6 Integrated relaxation pressure (IRP) corresponds to the mean pressure of 4s of greatest post-deglutitive relaxation in a 10-s gap, triggered at the
beginning of a swallow. Note diaphragmatic contraction pressure (*) during
relaxation excluded from the analysis
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Any mechanical or functional abnormality that creates an
obstruction at the EGJ can elevate the IRP (achalasia, neoplasms,
or strictures at the EGJ, hiatal hernias, and antireux surgery.
Step 2: Assess Esophageal Body Function
(Table11.1) (Fig.11.7)
• Main esophageal contractility metrics:
Contraction Vigor The DCI is a measure of the contractile (per-
istaltic) force of esophageal contraction (mm Hg/s/cm). Each
swallow is dened based on the DCI as either normal (DCI >450,
but <8000), failed (DCI<100), weak (DCI >100, but <450mm),
Table 11.1 Characteristics of deglutitive peristaltic function proposed for
the Chicago Classication v3.0 (note that contraction pattern is not scored
with failed or weak vigor)
Contractile vigor
Failed DCI<100mmHg-s-cm
Weak DCI>100mmHg-s-cm, but <450mmHg-
s- cm
Ineffective Failed or weak
Normal DCI>450mmHg-s-cm but <8000mmHg-
s- cm
Hypercontractile
Contraction pattern
Premature DL<4.5s
Fragmented Large break (>5cm) in the 20mmHg
Intact Not achieving the above diagnostic criteria
Intrabolus pressure pattern (30mmHg isobaric contour referenced to
atmospheric)
Panesophageal
pressurization
Compartmentalized
esophageal pressurization
EGJ pressurization Pressurization restricted to zone between the
Normal No bolus pressurization >30mmHg
DCI≥8000mmHg-s-cm
isobaric contour, but not failed and
DCI>450mmHg-s-cm
Uniform pressurization of >30mmHg
extending from the UES to the EGJ
Pressurization of >30mmHg extending from
the contractile front to the EGJ
LES and CD in conjunction with LES-CD
separation
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GHI
Fig. 11.7 Contractile vigor as assessed using the DCI and contraction pattern. A contraction with a DCI <100mmHg-s-cm is failed (a); a contraction
with a DCI>100 but <450mmHg-s-cm is weak (b); and a hypercontractile
swallow is dened as a DCI >8000mmHg-s-cm (c). Premature contraction is
dened as a distal latency (DL) <4.5 s (d). A weak contraction
(DCI<450mmHg-s-cm) with reduced distal latency is considered failed (e).
A contraction with a normal DCI (450–8000mmHg-s-cm) and a break >5cm
is a fragmented contraction (f)
ineffective (failed or weak), or hypercontractile (DCI ≥ 8000)
using the 20-mmHg isobaric contour (IBC) tool (Fig.11.8).
Contraction Pattern Distal latency (DL) is the time interval in
seconds between the relaxation of the UES and the inection
point along the isobaric contour of 30mm Hg where the velocity
of propagation slows. DL is an indirect measure of swallowing
inhibition and therefore of normal peristalsis (Fig.11.9). A measurement of less than 4.5s and a DCI > 450 dene a premature
contraction. Fragmented contractions are considered segmental
defects (break in the 20-mmHg isobaric contour >5cm) with normal contraction vigor.
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