Esophageal Manometry Technique

Updated: Sep 09, 2016
  • Author: Philip O Katz, MD, FACP, FACG; Chief Editor: Kurt E Roberts, MD  more...
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Technique

Approach Considerations

During the 1950s, different types of water-filled catheters were used for esophageal manometry studies. Although the initial technology was limited, it evolved in ways that allowed further understanding of esophageal motility and subsequent development of more sophisticated catheters.

This system was used exclusively until the 1970s, when the first solid-state transducer was developed and slowly started to replace water-filled catheters as the preferred method. During the next 20 years, a number of studies were performed to try to establish what would be considered normal values for esophageal pressure dynamics.

Before studies are performed, the esophageal manometry catheter must be measured against a ruler to verify accuracy. The most distal recording point represents the zero point; usually, when the catheter is introduced into the patient, the number seen at the nose corresponds to the measured distance to the zero point. The specific distances between the different transducers must also be known; in current practice, modern computer software extrapolates the information regarding the space between the transducers. [7]

Another step to be performed prior to the study is calibration—that is, applying a known pressure to the transducers of the solid-state system by placing the catheter within a mercury manometer and seeing what number is actually displayed on the screen. The water-perfusion catheter is calibrated by recording pressures generated as air within the system is compressed. Failure to display the expected pressures should warrant further investigation prior to the study. [8]

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Procedure

Help take the procedure off the patient's mind by actively involving him or her in the process. With the patient sitting up (having already anesthetized the nostril and the throat a couple of minutes before), have the patient hold a cup of water with a straw in one hand and the catheter connector in the other.

Apply a water-based lubricant to the first 5 cm of the catheter tip. With the chin slightly tilted down, begin to pass the catheter slowly through the sinuses. Point the catheter tip towards the patient's contralateral earlobe as if crossing the floor of the sinuses. After passing the catheter about 12 cm, the tip will likely be at the level of the hypopharynx, where it usually will not generate a gag reflex. It is at this point that the patient may feel the catheter in the back of the throat.

Next, have the patient keep the shoulders down (to control gagging), and have him or her start taking small but continuous sips of water through the straw with relaxed swallows. Slowly start advancing the catheter, 3-4 cm at a time. Drinking water in this fashion will help maintain relaxation of the lower esophageal sphincter (LES) while contractile activity in the esophageal body is inhibited.

The catheter will have reached the stomach when the most distal transducer shows an increase in pressure as it passes the LES, with a subsequent drop. Afterward, place the patient in the supine position. Confirm that the transducers are in the stomach by asking the patient to take a deep breath; inspiration causes pressure in the abdominal cavity to rise, whereas expiration causes pressure to go down.

At this point, withdraw the catheter from the stomach, 1 cm at a time, keeping watch for an increase in pressure that will signal when the transducer is crossing the LES. The tracing must be marked each time the catheter is moved.

When the Medtronic high-resolution manometry (HRM) system (ManoScan; Covidien, Minneapolis, MN) is used, visualization of the LES and the upper esophageal sphincter (UES) on the computer screen and noting the catheter position at the nares will allow the procedure to move forward. The catheter should then be taped to the nose to keep it in place.

With the Sandhill HRM system (inSIGHT Ultima; Sandhill Scientific, Milwaukee, WI), a gastric baseline is obtained, and the catheter must then be withdrawn and positioned on a horizontal line, which is displayed on the computer screen. As with the other system, at this time the study can move forward with swallows.

With the most distal circumferential transducer in the LES, give ten 5-mL water swallows to the patient with 20-30 seconds in between to evaluate the LES relaxation pattern and the contraction of the smooth-muscle distal esophagus. After these sips, pull the catheter out further, 0.5 cm at a time, allowing the patient to take a few breaths between moves without swallowing (keeping the mouth slightly open suppresses the need to swallow).

In HRM, the catheter remains in place; however, readers are encouraged to follow their system guidelines. With either HRM system, some transducers will remain in the stomach; thus, it is not the most distal transducer that is providing readings at the LES. 

The proximal LES border is at the point where the pattern changes to show thoracic pressures (decrease with inspiration, increase on expiration). This decrease in pressure with inspiration is known as the respiratory or pressure inversion point. 

When the area of maximal UES pressure is reached, manipulate the catheter so as to place the most proximal transducer 1 cm below the sphincter. This time, give five 5-mL water swallows; this allows evaluation of the skeletal muscle. In HRM, no movement of the catheter is necessary to gather these data.

Being able to pinpoint the location of the UES also aids in determining the length of the esophagus for subsequent pressure interpretation and possible pH probe positioning. To study the UES itself and the pharynx, the patient is then placed in an upright sitting position. The catheter is withdrawn in the same fashion as mentioned above until the distal transducer is located at the high-pressure zone of the UES.

When the catheter reaches the proximal border of the sphincter, the pressure will drop. At this time, six 5-mL water swallows are performed. An M-shaped configuration pattern should be observed with each swallow as the UES elevates onto the transducer (first pressure spike), then relaxes (first pressure fall), closes (second pressure spike), and finally descends onto its original starting position (second pressure fall).

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Analysis

Once the study is complete, the analysis of the recorded pressures and the knowledge of the distance between the recording points allows analysis of the results.

For example, assume that the proximal LES is found at 46 cm and the distal LES at 50 cm. In this case, the LES is approximately 4 cm in length (50 – 46 = 4 cm). Swallows are then performed with the distal transducer in the LES high-pressure zone at 47 cm, and with the transducers 5 cm apart within one another, the distal esophagus is studied with transducers at 42, 37, and 32 cm (ie, at 5, 10, and 15 cm above the LES).

Suppose that the UES is then located at 18 cm from the nares and the proximal esophagus was studied at 19, 24, 29, and 34 cm (ie, 1, 6, 11, and 16 cm below the UES). By mapping out these locations, the esophageal length is calculated to be 28 cm by subtracting the proximal LES position from the UES location (46 –18 = 28 cm).

In plotting the transducer positions, one is able to see that some overlapped during the study, and numbers obtained from them should be comparable. Esophageal length usually ranges between 18 and 28 cm and LES length between 3 and 5 cm.

Once the values are recorded within their anatomic location, further analysis is carried out. Given that manometric result recording is largely computer-based, the option for automated analysis would be beneficial, in that it could potentially lead to a decrease in interoperator variability and further standardization of results. However, this has not been perfected to the point where it could substitute for expert clinician analysis; clear cutoffs do not exist in certain areas where artifact could be distinguished from true peristaltic contractions. [9]

Analysis of manometric data has been enhanced by topographic data presentation through HRM (see the image below). As the name implies, HRM is a method of axial data interpolation derived from information obtained from multiple recording sites. The information is then presented as a three-dimensional [10] or two-dimensional contour plot in which ranges of pressure amplitude are represented by color or grayscale gradient or concentric rings. [11] This provides a snapshot and allows dynamic representation of motility and peristalsis along the body of the esophagus.

High-resolution manometry catheter. Note multiple High-resolution manometry catheter. Note multiple pressure transducers (unidirectional and circumferential) and impedance recording broad rings.

Another technology that has been combined with manometry is intraluminal electrical impedance monitoring. This consists of pairs of metal rings dispersed along the catheter that quantify the impedance between them. Because air, fluids, and solids have unique impedance characteristics, the information provided allows the clinician to assess the effectiveness of intraluminal clearance and esophageal motor activity.

Manometric evaluation of the UES is complicated by its asymmetric and complex anatomy and by its movement during swallowing. The presence of the catheter itself also stimulates its contraction. Proximal esophageal contractions can be assessed for amplitude, but the normal values are not known; the clinical utility of this evaluation is therefore somewhat limited. However, when this is combined with concurrent fluoroscopy, it provides added insight into the understanding and evaluation of problems like Zenker diverticula and cricopharyngeal bars.

Regarding the esophageal body, manometry has shown that bolus transit through the esophageal body does not occur in a single smooth wave; rather, it reflects a sequence of contractions that occur within four pressure segments extending from the UES to the LES. Associated with proper distal esophageal emptying is a peristaltic amplitude of greater than 30 mm Hg; this cutoff has a specificity of 66% and a sensitivity of 85% for identifying incomplete bolus transit.

The esophagogastric junction (EGJ) pressures are a result of the combination of the intrinsic LES tone with pressure contributed by the right crus of the diaphragm; this allows for a wide range in what is considered normal values within end inspiration and end expiration. However, a significantly low value (<5 mm Hg) is definitely considered abnormal.

Additionally, the most important measurement obtained during esophageal manometry is probably the value of LES relaxation; great advances in determining what is considered normal values have been achieved after the introduction of HRM. (See the image below.)

Normal high-resolution manometry with impedance. U Normal high-resolution manometry with impedance. Upper one third of image represents impedance portion, where purple bands representing passage of bolus are separated by white areas that represent complete esophageal emptying. In lower two thirds of image, note normal upper esophageal resting pressure with complete relaxation (top orange band) followed by progressive peristaltic waves of esophageal body (orange vertical bands) and subsequent lower esophageal relaxation. Note absence of pressurized esophagus in between swallows, represented by blue-green areas in between. Lower esophageal sphincter pressure returns to baseline after bolus passes (lower orange band). This sequence is seen over and over. Image courtesy of R Matthew Gideon, Albert Einstein Medical Center.

Table 1 below summarizes some values used to determine normal esophageal function and primary motility disorders.

Table 1. Criteria for Normal Esophageal Function and Primary Motility Disorders (Open Table in a new window)

Motility pattern LES resting pressure



(10-45 mm Hg)



LES relaxation residual



(≤8 mm Hg or, in HRM, <15 mm Hga or ≤20 mm Hgb)



Effective peristaltic waves in distal esophagus (≥30 mm Hg) at 5 and 10 cm above LES Ineffective peristaltic waves in distal esophagus (<30 mm Hg) at 3 and/or 8 cm above LES Simultaneous contractions (>30 mm Hg) at propagation rate ≥8 cm/s
Normal 10-45 mm Hg ≤8 mm Hg ≥7 waves ≤2 waves ≤1 contraction
Achalasia Normal (≤45 mm Hg)



Abnormal (>45 mm Hg)



>8 mm Hg 0 0 10 contractions
Distal esophageal spasm Normal (≤45 mm Hg) Normal



(≤8 mm Hg)



1-8 ≤2 waves ≥2 contractions



≤9 contractions



Hypercontractile motility



Hypertensive LES



Nutcracker esophagus



 



>45 mm Hg



 



≤8 mm Hg



 



7-10 wavesc



 



≤2 waves



 



≤1 contraction



Hypocontractile motility



Hypotensive LES



Ineffective esophageal motility



 



<10 mm Hg



 



≤8 mm Hg



 



0-7 waves



 



3-10 waves



 



≤1 contraction



a LES integrated relaxation pressure in medtronic HRM system.



b LES integrated relaxation pressure in Sandhill HRM system.



c Average amplitude of 10 swallows (20 contractions 5 and 10 cm above LES) >180 mm Hg.



LES = lower esophageal sphincter.



Data from Gideon RM. Manometry: Technical issues. Gastrointest Endoscopy Clin N Am 2005;15:243-255.



Chicago classification

The Chicago Classification for HRM creates a simplified and standardized way of analyzing the data from an HRM study to diagnose esophageal motility disorders. [12] The three main measurements obtained by HRM that are used to make diagnoses are as follows:

  • Integrated relaxation pressure (IRP)
  • Distal latency (DL)
  • Distal contractile integral (DCI)

The first decision point centers on evaluating the IRP as either normal (<15 mm Hg) or abnormal (>15 mm Hg). Conditions with an abnormal IRP include the following [12] :

  • Type I, II, and III achalasia
  • EGJ outflow obstruction

Conditions with a normal IRP are subdivided into the following categories [12] :

  • Major disorders of peristalsis - These include hypercontractile esophagus (jackhammer), distal esophageal spasm (DES), and absent contractility
  • Minor disorders of peristalsis - These include fragmented peristalsis and ineffective esophageal motility (IEM)
  • Normal motility

The Chicago Classification eliminates the diagnoses of hypertensive LES, nutcracker esophagus, hypotensive LES, and hypocontractile LES. 

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Common Manometric Abnormalities

Gastroesophageal reflux disease

Although one would assume that gastroesophageal reflux disease (GERD) should be consistently associated with low EGJ pressure, more than 95% of these patients have a basal LES pressure higher than 10 mm Hg. [13]  This is probably related to the fact that transient LES relaxation episodes can occur outside the timeframe in which the study is performed. Esophageal body peristalsis can also be impaired, with failed contractions of less than 30 mm Hg leading to impaired volume clearance (ie, ineffective esophageal motility). However, although these abnormalities are associated with GERD, they are not pathognomonic.

As regards management, manometry is used in determining proper probe positioning for esophageal pH monitoring and aids in the preoperative and postoperative evaluation of antireflux surgery. However, there is a poor correlation between the results of preoperative manometry and the postoperative success and resolution of symptoms; it is mainly used to rule out other causes of symptoms if an alternative diagnosis is being considered. [14] After surgery, manometry can help determine whether the cause of dysphagia is related to an underlying motility problem or to a surgical complication.

Achalasia

The classic manometric findings of achalasia include smooth muscle esophageal aperistalsis and impaired relaxation of the lower esophageal sphincter/esophagogastric junction. The intramural myenteric plexus neurons that are absent in this condition promote lower esophageal sphincter relaxation and propagation of peristalsis, which explains these findings. Of note, a few manometric pattern variants of this condition exist, which show its complex nature, as follows:

In achalasia type I (see the image below), there is no significant esophageal body pressurization; this subtype is more likely to present with endoscopic evidence of esophageal dilation. The Chicago classification categorizes type I achalasia as having a median IRP greater than 15 mm Hg and failed peristalsis with all swallows. [12]

High-resolution manometry of patient with achalasi High-resolution manometry of patient with achalasia type I. Top one third (in purple) represents fluid-filled esophagus by impedance, with incomplete emptying between swallows. Below this, upper horizontal dark-red band represents upper esophageal sphincter; orange band at bottom with interspersed dark-red areas represents lower esophageal sphincter. In between these two bands, it can be noted that there is no panesophageal pressurization and no peristalsis in the esophageal body. Image courtesy of R Matthew Gideon, Albert Einstein Medical Center.

The manometric pattern of achalasia type II (see the image below) shows compartmentalized esophageal pressurization, which can span the whole length of the esophageal body. Of the three types of achalasia, type II is considered to have the best rate of response to treatment. The Chicago classification categorizes type II achalasia as having a median IRP greater than 15 mm Hg with 100% failed peristalsis with panesophageal pressurization in at least 20% of swallows. [12]

High-resolution manometry of patient with achalasi High-resolution manometry of patient with achalasia type II. Top one third (in purple) represents fluid-filled esophagus by impedance. Bottom two thirds (in orange) represents pressurized esophagus. Dark-red band at top of orange area represents upper esophageal sphincter (UES); dark-red band at bottom represents lower esophageal sphincter (LES). Note isobaric simultaneous contractions and elevated intraesophageal pressure (orange area) along with impaired LES relaxation (high resting pressure and incomplete relaxation). Image courtesy of R Matthew Gideon, Albert Einstein Medical Center.

Achalasia type III (see the image below) is characterized by spastic contractions, which can even obliterate the esophageal lumen; this type is considered to be predictive of a lower treatment response than is seen with types I and II. [15]  The Chicago classification categorizes type III achalasia as having a median IRP greater than 15 mm Hg with no normal peristalsis and at least 20% of swallows with premature contractions (defined as a DL <4.5 s and a DCI >450 mm Hg⋅s⋅cm). [12]

High-resolution manometry of patient with achalasi High-resolution manometry of patient with achalasia type III. Top one third represents impedance portion of study. In bottom two thirds, in between orange horizontal bars representing upper and lower esophageal sphincters, vertical bands that represent esophageal body contractions can be seen. Note areas that are equivalent to spastic contraction, which can even obliterate esophageal lumen. Image courtesy of R Matthew Gideon, Albert Einstein Medical Center.

Further studies regarding the subclassification of achalasia are necessary to fully understand the different diagnostic and treatment strategies and the impact it has on patients' symptoms and disease course. [16]

Isobaric simultaneous contractions and elevated intraesophageal pressure support the diagnosis of achalasia; however, these manometric findings are undistinguishable from Chagas disease. The presence of impaired lower esophageal sphincter relaxation differentiates achalasia from other conditions in which esophageal aperistalsis can be present (eg, diabetes and GERD), but is unable to distinguish it from Chagas disease.

Esophagogastric junction outflow obstruction

EGJ outflow obstruction is characterized by a median IRP higher than 15 mm Hg that does not meet the criteria for achalasia I,II, or III. [12]  The etiology of EGJ outflow obstruction has been postulated to be secondary to early achalasia or infiltrative disorders or to represent the manometric findings of a hiatal hernia.

Distal esophageal spasm

DES still has an unclear etiology, but what is known is that it is associated with intermittent abnormal esophageal contractions that can cause dysphagia, chest pain, or both. Although the presence of simultaneous contractions is characteristic, as many as 20% of healthy volunteers are found to have them in the absence of symptoms (probably because of their low amplitude).

Some have proposed that a minimum amplitude of 20 mm Hg should be necessary for diagnosis. [17]  The Chicago classification defines this condition as having a normal median IRP with at least 20% of swallows characterized by premature (DL <4.5 s) contractions with a DCI higher than 450 mm Hg⋅s⋅cm. 

A further debate that has risen, however, is whether DES should be considered a motor disorder in and of itself. If one limits the definition to meeting exactly all the criteria, it would be a very rare condition. If the defining parameters are broadened, it would be overdiagnosed.

Hypercontractile esophagus

The category of hypercontractile motility disorders has included nutcracker esophagus (increased mean amplitude >180 mm Hg with normal peristalsis and prolonged distal esophageal contraction) and hypertensive LES (resting pressure greater than 45 mm Hg with possible impaired relaxation). (See the image below.) On the basis of the Chicago Classification, the diagnosis of nutcracker esophagus has been eliminated and replaced by jackhammer esophagus. [12]

Tracings of patient with nutcracker esophagus. Inc Tracings of patient with nutcracker esophagus. Increased mean amplitude >180 mm Hg with normal peristalsis and prolonged distal esophageal contraction can be seen; main problem stems from excess contractility either of lower esophageal sphincter or of esophageal body. Image courtesy of R Matthew Gideon, Albert Einstein Medical Center.

As the name suggests, the main problem in hypercontractile motility disorders stems from excess contractility of the LES, the esophageal body, or both. These disorders are not fixed and may therefore vary and evolve into another form of motility disorder over time.

Jackhammer esophagus

Jackhammer esophagus is defined as a normal median IRP with at least two swallows with a DCI greater than 8000 mm Hg⋅s⋅cm (see the image below). The DCI is measured from the transition zone to the proximal LES; however, in instances where the hypercontractility appears to involve the LES, the DCI should be extended to include the LES to obtain the accurate diagnosis. [12]

Representative swallow in patient with diagnosed j Representative swallow in patient with diagnosed jackhammer esophagus. DCI is 19,852 mm Hg∙s∙cm with IRP of 13.6 mm Hg. In this swallow, lower esophageal sphincter exhibits contractility and is included in calculation of DCI.

Absent contractility

Absent contractility is defined as a normal median IRP with 100% failed peristalsis. In situations when the IRP is close to 15, it is prudent to consider type I achalasia as a diagnosis. Additionally, when the DL is less than 4.5 seconds and the DCI is less than 450 mm Hg⋅s⋅cm, a diagnosis of failed peristalsis should be considered. Absent contractility is considered to be a major disorder of peristalsis. [12]

Ineffective esophageal motility

IEM is defined as a normal median IRP and 50% or more ineffective swallows. An ineffective swallow is defined as a DCI less than 450 mm Hg⋅s⋅cm. This condition is considered to be a minor disorder of peristalsis. [12]

Fragmented peristalsis

Fragmented peristalsis is defined as at least 50% of swallows with a DCI greater than 450 mm Hg⋅s⋅cm and a break of 5 cm or more. It also must not meet the criteria for IEM. [12]

Hypocontractile motility disorders

The main problem in hypocontractile motility disorders is a lack of tone or contractility involving the LES or esophageal peristalsis. A hypotensive LES is defined by a resting pressure of less than 10 mm Hg, whereas ineffective esophageal motility is characterized by 30% or more low distal amplitude contractions (<30 mm Hg). Version 3.0 of the Chicago classification eliminates the diagnosis of hypocontractile esophagus, replacing it with the diagnosis of absent contractility. [12]

Multisystem/collagen vascular diseases

The pattern observed in these cases include aperistalsis in the distal two thirds of the esophagus (smooth muscle) and diminished or absent LES tone. In contrast, UES tone and proximal esophageal function are preserved. However, this constellation is not pathognomonic for diagnosis and can be sometimes seen in other conditions, such as GERD.

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Complications

Esophageal manometry is a generally safe procedure, and complications are usually few and mild (eg, gagging and watery eyes during the catheter insertion, sore throat, rhinorrhea, and epistaxis). More severe complications occur rarely and may include arrhythmias, vasovagal episodes, bronchospasm, and aspiration. To our knowledge, there has only been a single report of esophageal perforation with this procedure. [18]

In situations where manometry must be performed despite the presence of relative contraindications, precautions such as endoscopic or radiologic guidance must be performed to decrease the risk of complications.

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