Determinants of pressure drift in Manoscan(™) esophageal high-resolution manometry system

How to effectively use and interpret the barium swallow: Current role in esophageal dysphagia

BACKGROUND

The barium swallow is a commonly performed investigation, though recent decades have seen major advances in other esophageal diagnostic modalities.

PURPOSE

The purpose of this review is to clarify the rationale for components of the barium swallow protocol, provide guidance on interpretation of findings, and describe the current role of the barium swallow in the diagnostic paradigm for esophageal dysphagia in relation to other esophageal investigations. The barium swallow protocol, interpretation, and reporting terminology are subjective and non-standardized. Common reporting terminology and an approach to their interpretation are provided. A timed barium swallow (TBS) protocol provides more standardized assessment of esophageal emptying but does not evaluate peristalsis. Barium swallow may have higher sensitivity than endoscopy for detecting subtle strictures. Barium swallow has lower overall accuracy than high-resolution manometry for diagnosing achalasia but can help secure the diagnosis in cases of equivocal manometry. TBS has an established role in objective assessment of therapeutic response in achalasia and helps identify the cause of symptom relapse. Barium swallow has a role in the evaluating manometric esophagogastric junction outflow obstruction, in some cases helping to identify where it represents an achalasia-like syndrome. Barium swallow should be performed in dysphagia following bariatric or anti-reflux surgery, to assess for both structural and functional postsurgical abnormality. Barium swallow remains a useful investigation in esophageal dysphagia, though its role has evolved due to advancements in other diagnostics. Current evidence-based guidance regarding its strengths, weaknesses, and current role are described in this review.

Functional Lumen Imaging Probe Panometry Helps Identify Clinically Relevant Esophagogastric Junction Outflow Obstruction per Chicago Classification v4.0

INTRODUCTION

Esophagogastric junction (EGJ) outflow obstruction (EGJOO) per Chicago Classification v4.0 (CCv4.0) represents a high-resolution manometry (HRM) diagnosis with uncertain clinical significance. This study aimed to evaluate functional lumen imaging probe (FLIP) panometry among patients with EGJOO on HRM/CCv4.0 to assess clinical/manometric associations and treatment outcomes.

METHODS

An observational cohort study was performed on patients who completed FLIP during endoscopy and had an HRM/CCv4.0 diagnosis of EGJOO, i.e., HRM-EGJOO (inconclusive). Abnormal FLIP panometry motility classifications were applied to identify FLIP-confirmed conclusive EGJOO. Rapid drink challenge on HRM and timed barium esophagram were also assessed. Clinical management plan was determined by treating physicians and assessed through chart review. Clinical outcome was defined using the Eckardt score (ES) during follow-up evaluation: ES < 3 was considered a good outcome.

RESULTS

Of 139 adult patients with manometric EGJOO (inconclusive per CCv4.0), a treatment outcome ES was obtained in 55 after achalasia-type treatment (i.e., pneumatic dilation, peroral endoscopic myotomy, laparoscopic Heller myotomy, or botulinum toxin injection) and 36 patients after other nonachalasia-type treatment. Among patients with conclusive EGJOO by HRM-FLIP complementary impression, 77% (33/43) had a good outcome after achalasia-type treatment, whereas 0% (0/12) of patients had a good outcome after nonachalasia-type treatment. Of patients with normal EGJ opening on FLIP, one-third of patients treated with achalasia-type treatment had a good outcome, while 9 of the 10 treated conservatively had a good outcome.

DISCUSSION

FLIP panometry provides a useful complement to clarify the clinical significance of an HRM/CCv4.0 EGJOO diagnosis and help direct management decisions.

New Internet of Medical Things for Home-Based Treatment of Anorectal Disorders

Home-based healthcare provides a viable and cost-effective method of delivery for resource- and labour-intensive therapies, such as rehabilitation therapies, including anorectal biofeedback. However, existing systems for home anorectal biofeedback are not able to monitor patient compliance or assess the quality of exercises performed, and as a result have yet to see wide spread clinical adoption. In this paper, we propose a new Internet of Medical Things (IoMT) system to provide home-based biofeedback therapy, facilitating remote monitoring by the physician. We discuss our user-centric design process and the proposed architecture, including a new sensing probe, mobile app, and cloud-based web application. A case study involving biofeedback training exercises was performed. Data from the IoMT was compared against the clinical standard, high-definition anorectal manometry. We demonstrated the feasibility of our proposed IoMT in providing anorectal pressure profiles equivalent to clinical manometry and its application for home-based anorectal biofeedback therapy.

Dysphagia: Novel and Emerging Diagnostic Modalities

Among recent advances in diagnostics for dysphagia and esophageal motility disorders is the update to the Chicago Classification (version 4.0) for interpretation of high-resolution manometry (HRM) and diagnosis of esophageal motility disorders. The update incorporates application of complementary testing strategies during HRM, such as provocative HRM maneuvers, and recommendation for barium esophagram or functional luminal imaging probe (FLIP) panometry to help clarify inconclusive HRM findings. FLIP panometry also represents an emerging technology for evaluation of esophageal distensibility and motility at the time of endoscopy.

Prediction of Esophageal Retention: A Study Comparing High-Resolution Manometry and Functional Luminal Imaging Probe Panometry

INTRODUCTION

High-resolution manometry (HRM) is generally considered the primary method to evaluate esophageal motility; functional luminal imaging probe (FLIP) panometry represents a novel method to do so and is completed during sedated endoscopy. This study aimed to compare HRM and FLIP panometry in predicting esophageal retention on timed barium esophagram (TBE).

METHODS

A total of 329 adult patients who completed FLIP, HRM, and TBE for primary esophageal motility evaluation were included. An abnormal TBE was defined by a 1-minute column height >5 cm or impaction of a 12.5-mm barium tablet. The integrated relaxation pressure (IRP) on HRM was assessed in the supine and upright patient positions. Esophagogastric junction (EGJ) opening was evaluated with 16-cm FLIP performed during sedated endoscopy through EGJ-distensibility index and maximum EGJ diameter.

RESULTS

Receiver operating characteristic curves to identify an abnormal TBE demonstrated AUC (95% confidence interval) of 0.79 (0.75-0.84) for supine IRP, 0.79 (0.76-0.86) for upright IRP, 0.84 (0.79-0.88) for EGJ-distensibility index, and 0.88 (0.85-0.92) for maximum EGJ diameter. Logistic regression to predict abnormal TBE showed odds ratios (95% confidence interval) of 1.8 (0.84-3.7) for consistent IRP elevation and 39.7 (16.4-96.2) for reduced EGJ opening on FLIP panometry. Of 40 patients with HRM-FLIP panometry discordance, HRM-IRP was consistent with TBE in 23% while FLIP panometry was consistent with TBE in 78%.

DISCUSSION

FLIP panometry provided superior detection of esophageal retention over IRP on HRM. However, application of a complementary evaluation involving FLIP panometry, HRM, and TBE may be necessary to accurately diagnose esophageal motility disorders.

Esophagogastric junction outflow obstruction

In the Chicago Classification version 4.0 (CCv4), esophagogastric junction outflow obstruction (EGJOO) is manometrically defined as an elevated median integrated relaxation pressure (IRP) and elevated intrabolus pressure (IBP) during supine wet swallows, and persistently elevated median IRP in the upright position. A clinically relevant conclusive diagnosis of EGJOO requires a manometric diagnosis of EGJOO and associated symptoms such as dysphagia and/or chest pain with at least one of the following supportive investigations (pharmacologic provocation, timed barium esophagogram, and/or endoflip). The Chicago Classification is intended for diagnosis of primary esophageal motor disorders, and thus history and endoscopic evaluation are important to exclude conditions (eg, previous surgery, strictures, or masses) that can secondarily generate the EGJOO pattern on HRM. While a manometric finding of EGJOO is often made and can be an early sign of achalasia, more often it is a manometric finding without clinical implications. The proposed changes in CC4.0 have attempted to make the diagnosis more specific, in order to reduce the number of clinically irrelevant diagnoses and avoid confusion by patients and physicians alike.

The Clinical Relevance of Manometric Esophagogastric Junction Outflow Obstruction Can Be Determined Using Rapid Drink Challenge and Solid Swallows

INTRODUCTION

Esophagogastric junction outflow obstruction (EGJOO) defined on high-resolution esophageal manometry (HRM) poses a management dilemma given marked variability in clinical manifestations. We hypothesized that findings from provocative testing (rapid drink challenge and solid swallows) could determine the clinical relevance of EGJOO.

METHODS

In a retrospective cohort study, we included consecutive subjects between May 2016 and January 2020 with EGJOO. Standard HRM with 5-mL water swallows was followed by provocative testing. Barium esophagography findings were obtained. Cases with structural obstruction were separated from functional EGJOO, with the latter categorized as symptom-positive or symptom-negative. Only symptom-positive subjects were considered for achalasia-type therapies. Sensitivity and specificity for clinically relevant EGJOO during 5-mL water swallows, provocative testing, and barium were calculated.

RESULTS

Of the 121 EGJOO cases, 76% had dysphagia and 25% had holdup on barium. Ninety-seven cases (84%) were defined as functional EGJOO. Symptom-positive EGJOO subjects were more likely to demonstrate abnormal motility and pressurization patterns and to reproduce symptoms during provocative testing, but not with 5-mL water swallows. Twenty-nine (30%) functional EGJOO subjects underwent achalasia-type therapy, with symptomatic response in 26 (90%). Forty-eight (49%) functional EGJOO cases were managed conservatively, with symptom remission in 78%. Although specificity was similar, provocative testing demonstrated superior sensitivity in identifying treatment responders from spontaneously remitting EGJOO (85%) compared with both 5-mL water swallows (54%; P < 0.01) and barium esophagography (54%; P = 0.02).

DISCUSSION

Provocative testing during HRM is highly accurate in identifying clinically relevant EGJOO that benefits from therapy and should be routinely performed as part of the manometric protocol.

Esophageal motility disorders on high-resolution manometry: Chicago classification version 4.0©

Chicago Classification v4.0 (CCv4.0) is the updated classification scheme for esophageal motility disorders using metrics from high-resolution manometry (HRM). Fifty-two diverse international experts separated into seven working subgroups utilized formal validated methodologies over two-years to develop CCv4.0. Key updates in CCv.4.0 consist of a more rigorous and expansive HRM protocol that incorporates supine and upright test positions as well as provocative testing, a refined definition of esophagogastric junction (EGJ) outflow obstruction (EGJOO), more stringent diagnostic criteria for ineffective esophageal motility and description of baseline EGJ metrics. Further, the CCv4.0 sought to define motility disorder diagnoses as conclusive and inconclusive based on associated symptoms, and findings on provocative testing as well as supportive testing with barium esophagram with tablet and/or functional lumen imaging probe. These changes attempt to minimize ambiguity in prior iterations of Chicago Classification and provide more standardized and rigorous criteria for patterns of disorders of peristalsis and obstruction at the EGJ.

Clinical Functional Lumen Imaging Probe Testing in Esophageal Disorders: A Need for Better Quality Evidence

In their article "Use of the Functional Lumen Imaging Probe in Clinical Esophagology," Savarino et al. report the outcomes of a Grading of Recommendations Assessment, Development, and Evaluation analysis performed by experts in the use of functional lumen imaging probe (FLIP) evaluation of esophageal disorders. For essentially all clinical indications, the recommendation for use was conditional with a very low quality of evidence. FLIP is an expensive, invasive technology examining limited aspects of esophageal function. Its role in complementing or replacing existing technology is uncertain, particularly when compared with manometric testing with additional provocative studies. Performing properly designed studies to demonstrate FLIP's true effectiveness and cost-effectiveness will be costly.

The role of ambulatory 24-hour esophageal manometry in clinical practice

High-resolution manometry revolutionized the assessment of esophageal motility disorders and upgraded the classification through the Chicago Classification. A known disadvantage of standard HRM, however, is the inability to record esophageal motility function for an extended time interval; therefore, it represents only a more snapshot view of esophageal motor function. In contrast, ambulatory esophageal manometry measures esophageal motility over a prolonged period and detects motor activity during the entire circadian cycle. Furthermore, ambulatory manometry has the ability to measure temporal correlations between symptoms and motor events. This article aimed to review the clinical implications of ambulatory esophageal manometry for various symptoms, covering literature on the manometry catheter, interpretation of findings, and relevance in clinical practice specific to the evaluation of non-cardiac chest pain, chronic cough, and rumination syndrome.

Diagnostic differences in the pharmacologic response to cholecystokinin and amyl nitrite in patients with absent contractility vs type I Achalasia

BACKGROUND

Absent esophageal contractility (AC) is distinguished from type 1 achalasia (ACH1) during high-resolution manometry (HRM) on the basis of normal or elevated deglutitive integrated relaxation pressure (IRP) values. However, IRP measurements are subject to pressure recording error. We hypothesized that distinctive responses to pharmacologic provocation using amyl nitrite (AN) and cholecystokinin (CCK) could reliably distinguish AC patients from those with ACH1.

AIM

To compare esophageal response with AN and CCK in a well-defined cohort of ACH1 and AC patients.

METHOD

All available clinical, radiographic, endoscopic, and manometric information in 34 patients with aperistalsis was reviewed to determine the final diagnosis of ACH1 and AC. The differences in response to provocative challenges with the rapid drink challenge (RDC) test and administration of AN and CCK were compared between these two groups.

RESULTS

Eighteen patients were diagnosed with ACH1 and sixteen with AC. While IRP values were significantly higher in ACH1, the standard criterion value misclassified four AC patients as having ACH1 and five ACH1 patients as having AC. IRP values on the RDC did not accurately segregate AC from ACH1, but we were able to identify AN and CCK esophageal motor response criteria that allowed correct classification of ACH1 and AC patients.

CONCLUSIONS

Nearly a quarter of AC and ACH1 patients may be misdiagnosed based on manometric IRP criteria alone. Differences in the esophageal motor responses to AN and CCK have the potential to facilitate the correct diagnosis in these challenging patients.

Performing High-resolution Impedance Manometry After Endoscopy With Conscious Sedation Has Negligible Effects on Esophageal Motility Results

Background/Aims

High-resolution manometry (HRM) performed without sedation is the standard procedure. However, some patients cannot tolerate transnasal placement of the manometry catheter. We aim to assess the practice of performing manometry after endoscopy with conscious sedation by evaluating its impact on esophageal motility findings.

Methods

Twelve asymptomatic adult volunteers and 7 adult patients completed high-resolution impedance manometry (HRIM) approximately 1 hour after conscious sedation with midazolam and fentanyl (post-sedation) and again on a different day with no-sedation. The nosedation HRIM involved 2 series of swallows separated in time by 20 minutes (no-sedation-1 and no-sedation-2) for the volunteers; patients completed only 1 series of swallows for no-sedation HRM.

Results

A motility diagnosis of normal motility was observed in all 12 volunteers post-sedation. Two volunteers had a diagnosis of borderline ineffective esophageal motility, one during the no-sedation-1 period and the other during the no-sedation-2 period; all of the other no-sedation HRIM studies yielded a normal motility diagnosis. Six of seven patients had the same diagnosis in both no-sedation and post-sedation HRM, including 1 distal esophageal spasm, 3 achalasia (2 type II and 1 type III), and 2 esophagogastric junction outflow obstruction. Only one patient's HRM classification changed from ineffective esophageal motility at no-sedation to normal esophageal motility at post-sedation.

Conclusions

Performing HRIM after endoscopy with conscious sedation had minimal clinical impact on the motility diagnosis or motility parameters. Thus, this approach may be a viable alternative for patients who cannot tolerate unsedated catheter placement.

Pharmacologic interrogation of patients with esophagogastric junction outflow obstruction using amyl nitrite

BACKGROUND

The Chicago Classification of esophageal motility includes a group of patients who show evidence of esophagogastric junction outflow obstruction (EGJOO) as demonstrated by elevated integrated relaxation pressure (IRP) and preserved peristalsis. Our aim is to classify EGJOO patients based on response to amyl nitrite (AN) during high-resolution manometry.

METHODS

Patients were considered to have true EGJOO if elevated IRP during supine swallow persisted in the upright position and was associated with high intrabolus pressure. The EGJ response to AN was compared between patients with achalasia type 2 (A2) and normal esophageal motility. Based on the relaxation gain (deglutitive IRP-AN IRP) value that best discriminated these two groups (10 mm Hg), patients with true EGJOO were categorized as being in either the AN-responsive (AN-R) or AN-unresponsive (AN-U) subgroups.

KEY RESULTS

In the group of 49 patients with true EGJOO, the AN response classified 27 patients (IRP = 25 ± 10 mm Hg) with AN-R and 22 patients (IRP = 20 ± 5 mm Hg) with AN-U (P = 0.2). In AN-R, AN produced a relaxation gain and rebound after-contraction response at the EGJ comparable to A2 patients. AN-U patients had an elevated IRP after AN and a relaxation gain similar to normal esophageal motility patients. AN-U patients were obese and had higher prevalence of sleep apnea (P < 0.05).

CONCLUSIONS

Among patients with true EGJOO, only half have pharmacologic evidence of impaired LES relaxation. Pharmacologic interrogation of the EGJ is thus necessary to identify the subgroup of EGJOO patients who could be expected to benefit from LES ablative therapies.

Roux Limb Motility in Gastric Bypass Patients with Chronic Abdominal Pain-Is There an Association to Prescribed Opioids?

BACKGROUND/AIM

A number of patients continue to suffer from chronic abdominal pain of unknown origin, which may also lead to a prolonged use of opioid analgesics. Symptoms of abdominal pain, nausea and vomiting in this patient group resemble the characteristics of the Roux stasis Syndrome. The aim was to elucidate relationships between chronic abdominal pain, Roux limb motor activity and opioid analgesics.

METHODS

Roux limb high-resolution manometry and ratings of abdominal pain and quality of life were analysed in 15 gastric bypass patients reporting abdominal pain of unknown origin. Effect of acute opiate administration (morphine i.v.) on fasting Roux limb motor activity was assessed in asymptomatic and morphine-naïve gastric bypass patients (n = 9) and compared with an untreated control group (n = 11).

RESULTS

In the symptomatic patient group, we found disturbed Roux limb motor patterns in 10 out of 15 examinations, but no signs of Roux stasis syndrome. A high prevalence of prescribed opioid analgesics as well as a high number of reoperations in this group. The worst quality of life and the highest number of pain-killing medications were observed among the patients with distal pacemaker activity in Roux limb. In the morphine-naïve and asymptomatic patients, morphine increased the muscular tone in the Roux limb during phase III-like motor activity. A majority of the RYGBP patients with chronic abdominal pain had a disturbed Roux limb fasting motility, and there was a high prevalence of prescribed opioid analgesics. In opiate-naïve RYGBP patients, acute morphine intravenously increased the muscular tone of the Roux limb.

Detailed measurements of oesophageal pressure during mechanical ventilation with an advanced high-resolution manometry catheter

Background

Oesophageal pressure (PES) is used for calculation of lung and chest wall mechanics and transpulmonary pressure during mechanical ventilation. Measurements performed with a balloon catheter are suggested as a basis for setting the ventilator; however, measurements are affected by several factors. High-resolution manometry (HRM) simultaneously measures pressures at every centimetre in the whole oesophagus and thereby provides extended information about oesophageal pressure. The aim of the present study was to evaluate the factors affecting oesophageal pressure using HRM.

Methods

Oesophageal pressure was measured using a high-resolution manometry catheter in 20 mechanically ventilated patients (15 in the ICU and 5 in the OR). Different PEEP levels and different sizes of tidal volume were applied while pressures were measured continuously. In 10 patients, oesophageal pressure was also measured using a conventional balloon catheter for comparison. A retrospective analysis of oesophageal pressure measured with HRM in supine and sitting positions in 17 awake spontaneously breathing patients is also included.

Results

HRM showed large variations in end-expiratory PES (PESEE) and tidal changes in PES (ΔPES) along the oesophagus. Mean intra-individual difference between the minimum and maximum end-expiratory oesophageal pressure (PESEE at baseline PEEP) and tidal variations in oesophageal pressure (ΔPES at tidal volume 6 ml/kg) recorded by HRM in the different sections of the oesophagus was 23.7 (7.9) cmH₂O and 7.6 (3.9) cmH₂O respectively. Oesophageal pressures were affected by tidal volume, level of PEEP, part of the oesophagus included and patient positioning. HRM identified simultaneous increases and decreases in PES within a majority of individual patients. Compared to sitting position, supine position increased PESEE (mean difference 12.3 cmH₂O), pressure variation within individual patients and cardiac artefacts. The pressure measured with a balloon catheter did not correspond to the average pressure measured with HRM within the same part of the oesophagus.

Conclusions

The intra-individual variability in PESEE and ΔPES is substantial, and as a result, the balloon on the conventional catheter is affected by many different pressures along its length. Oesophageal pressures are not only affected by lung and chest wall mechanics but are a complex product of many factors, which is not obvious during conventional measurements. For correct calculations of transpulmonary pressure, factors influencing oesophageal pressures need to be known. HRM, which is available at many hospitals, can be used to increase the knowledge concerning these factors.

Trial registration

ClinicalTrials.gov, NCT02901158

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2484-8) contains supplementary material, which is available to authorized users.

Correlates of Early Pharyngeal High-Resolution Manometry Adoption in Expert Speech-Language Pathologists

Pharyngeal high-resolution manometry (HRM) is at a point of entry into speech-language pathologist (SLP) clinical practice. However, the demographic characteristics of SLPs who are early adopters of HRM are unclear; perspectives of early adopters may shape how the technology is received by the field at large. We hypothesized that younger SLPs, those working in outpatient settings, those with a strong knowledge base in HRM, and those with experience in other types of instrumentation are more likely to have interest in adopting HRM. We surveyed the population of board-certified SLPs (BCS-S; n = 262) with a 33% response rate (n = 78). Firth logistic regression was used to determine differences in those expressing interest in adopting HRM into future practice (n = 28) and those who did not (n = 45) from the analytic sample of 73 respondents. The best fitting model predicted that SLPs: (1) with training in more types of instrumentation; and (2) believing they could explain the HRM procedure to a patient were more likely to plan to adopt pharyngeal HRM into regular clinical practice. Experience with a variety of instrumentation techniques may encourage SLPs to use new forms of technology. Knowledge of early adopter demographics will allow for development of targeted trainings and determination of HRM implementation barriers. Identification of a clinician sub-group more likely to adopt other new technologies in the future may also be possible.

Gastric accommodation in healthy subjects studied by ultrasound, manometry, and impedancemetry

BACKGROUND

Gastric accommodation to a meal may be important in the pathogenesis of upper gastrointestinal disorders, but has been difficult to investigate in a minimally invasive fashion.

METHODS

We studied gastric and lower esophageal physiology during food intake, combining transabdominal ultrasound, multichannel high-resolution impedance-manometry (HRIM) and a symptom questionnaire. A HRIM catheter was distally positioned at incisura angularis and 300 mL saline with 75 g glucose was ingested. Target variables were recorded for 30 min after fluid intake.

KEY RESULTS

Fifteen healthy subjects' participated (11W/4M, median age 23.8 y) and all accepted the meal with few symptoms. At incisura angularis maximum change in pressure from pre-intake values was -7.4 mmHg after 60 s (P < .0001), rising to pre-intake values within 20 min. The corresponding area increased significantly from pre-intake values of 8.0 cm² to 14.1 cm² shortly after intake (P = .0012), peaked at 5 min and slowly decreased towards 30 min. The corresponding maximum change in stress from pre-intake pressure values was -59.2 mmHg shortly after (P < .0001), reaching pre-intake values within 20 min. Strain rose from 0 shortly before to 0.36 shortly after (P < .0001), peaking at 5 min. At incisura angularis, fullness was positively correlated with area and to strain, while fullness, area, and stress were negatively correlated with pressure.

CONCLUSIONS & INFERENCES

The multimodal method enabled assessment of the gastric accommodation reflex, stress and strain in the stomach. It triggered few symptoms in healthy volunteers. We propose it to be a more physiological replacement of the barostat technique.

Pressure exposure and catheter impingement affect the recorded pressure in the Manoscan 360™ system

BACKGROUND

The accuracy of pressure measurements by Manoscan high-resolution manometry (HRM) system is affected by pressure drift (PD). The PD is partly related to temperature and study duration, but other factors that contribute to errant pressure recording have not been systematically evaluated. The aim of this study was to investigate and quantify contributing factors to pressure recording error.

METHODS

In total, 660 in vitro experiments were conducted on seven HRM catheters to determine the effects of sustained pressure exposure, catheter impingement, temperature, duration of study, and immersion in saline or acid on recorded pressure and PD.

KEY RESULTS

At room temperature and without application of pressure, the PD was negligible. Application of sustained pressure significantly increased PD and catheter impingement of even 15° produced remarkable increases in the recorded pressure as well as post-recording PD. There was significant variability across sensors in their propensity to develop PD with temperature. Body (37°C) and freezing (0°C) temperatures resulted in significantly higher absolute value of PD in the opposite algebraic direction, respectively (for individual sensors). Although the overall trend was for higher PD with increasing temperature, some of the pressure sensors demonstrated inherently negative PD at body temperature.

CONCLUSIONS AND INFERENCES

In addition to the known effects of temperature, both sustained pressure exposure and catheter impingement significantly affect the recorded pressure and the magnitude of the PD observed at the end of the recording. These effects can be substantial enough to result in erroneous manometric diagnoses.

High-resolution anorectal manometry: An expensive hobby or worth every penny?

Introduced approximately 10 years ago, high-resolution manometry catheters have fostered interest in anorectal manometry. This review, which accompanies two articles in this issue of Neurogastroenterology and Motility, reviews the methods, clinical indications, utility, and pitfalls of anorectal manometry and revisits the American Gastroenterological Association (AGA) Medical Position Statement on Anorectal Testing Techniques, which was last published in 1999. High-resolution manometry provides a refined assessment of the anorectal pressure profile, obviates the need for station pull-through maneuvers, and minimizes movement artifacts. In selected cases, this refined assessment may be useful for identifying structural abnormalities or anal weakness. However, many manometry patterns that were previously regarded as abnormal are also observed in a majority of healthy patients, which substantially limits the utility of manometry for identifying defecatory disorders. It is our impression that most conclusions of the AGA medical position statement from 1999 remain valid today. High-resolution techniques have not substantially affected the number of publications on or management of anorectal disorders. The ongoing efforts of an international working group to standardize techniques for anorectal manometry are welcome. Although high-resolution manometry is more than an expensive hobby, improvements in catheter design and further research to rigorously define and evaluate these techniques are necessary to determine if they are worth every penny.

Validation of criteria for the definition of transient lower esophageal sphincter relaxations using high-resolution manometry

BACKGROUND

Criteria for transient lower esophageal sphincter relaxations (TLESRs) are well-defined for Dentsleeve manometry. As high-resolution manometry (HRM) is now the gold standard to assess esophageal motility, our aim was to propose a consensus definition of TLESRs using HRM.

METHODS

Postprandial esophageal HRM combined with impedance was performed in 10 patients with gastroesophageal reflux disease. Transient lower esophageal sphincter relaxations identification was performed by 17 experts using a Delphi process. Four investigators then characterized TLESR candidates that achieved 100% agreement (TLESR events) and those that achieved less than 25% agreement (non-events) after the third round. Logistic regression and decision tree analysis were used to define optimal diagnostic criteria.

KEY RESULTS

All diagnostic criteria were more frequently encountered in the 57 TLESR events than in the 52 non-events. Crural diaphragm (CD) inhibition and LES relaxation duration >10 seconds had the highest predictive value to identify TLESR. Based on decision tree analysis, reflux on impedance, esophageal shortening, common cavity, upper esophageal sphincter relaxation without swallow and secondary peristalsis were alternate diagnostic criteria.

CONCLUSION & INFERENCES

Using HRM, TLESR might be defined as LES relaxation occurring in absence of swallowing, lasting more than 10 seconds and associated with CD inhibition.

Determinants and clinical impact of pressure drift in manoscan anorectal high resolution manometry system

BACKGROUND

Pressure drift (PD), resulting from differences between room and body temperature, reduces the accuracy of pressure measurements with the Manoscan high resolution manometry (HRM) system. Our aims were to assess PD during anorectal HRM.

METHODS

Defined as the residual pressure measured immediately after the catheter was removed, PD was calculated for each sensor and averaged across all 12 sensors in 454 anorectal consecutive studies recorded with 3 HRM catheters. The relationship between PD and study duration, number of prior uses of a catheter, and peak and average pressure exposure during a study were evaluated. The correction of PD with a software algorithm (thermal compensation) was evaluated in 76 studies where the most distal sensor was outside the body.

KEY RESULTS

The PD varied among sensors and across catheters. The average PD (7.3 ± 0.2 mmHg) was significantly greater for newer catheters, during longer studies, or when sensors were exposed to higher pressures. Together, these factors explained 81% of the variance in overall PD. After thermal compensation, the uncorrected median PD for the most distal sensor was 2.5-5 mmHg over the study duration. Correcting this changed the interpretation (e.g., as abnormal instead of normal) of at least 1 anorectal parameter in eight of 76 studies.

CONCLUSIONS & INFERENCES

During anorectal HRM, PD declines with catheter use and is greater for newer catheters, when sensors are exposed to higher pressures, and for studies of longer duration. While PD is partially corrected with thermal compensation algorithms, the impact on interpretation is modest.

Expanding Instrumental Options for Dysphagia Diagnosis and Research: Ultrasound and Manometry

Diagnostic assessment of swallowing in routine clinical practice relies heavily on the long-standing techniques of videofluoroscopic swallowing study (VFSS) and videoendoscopic evaluation of swallowing (VEES). These complementary and sophisticated techniques provide a real-time visualization of biomechanical movements of the structures involved in swallowing and consequent effects on bolus flow. Despite the sophistication of this instrumentation, interpretation relies heavily on subjective clinical judgement and temporal resolution is limited, limitations that may influence patient management. Adjunctive diagnostic assessments may be utilized to compensate for the limitations posed by VFSS and VEES. Ultrasound and pharyngeal manometry do not represent the latest in technological advances, with both emerging in swallowing research over 20 years ago. However, both have resisted integration into routine clinical practice, despite the fact that they offer quantitative metrics of swallowing that are not available using standard techniques. The aim of this review is to present recent research on these two less frequently used modalities in clinical swallowing assessment, discuss potential applications in clinical practice and review supportive data on test-retest reliability, rater reliability and validity. The paper will conclude with a case report that exemplifies the unique contribution of these modalities in executing and revising therapeutic approaches for a patient with neurogenic dysphagia.

Characterization and correction of pressure drift in the ManoScan(™) high-resolution manometry system: In vitro and in vivo

BACKGROUND

A substantial pressure drift in high-resolution manometry (HRM) has been reported; however, fundamental questions remain regarding the origin and management of this drift. The aim of this study was to provide critical in-depth analyses of ManoScan(™) HRM drift in vitro and in vivo.

METHODS

A total of sixteen 15-min studies and twelve 5-h studies were performed in a water bath at 37 °C at 4.0 cm depth (2.9 mmHg) with ESO and ESO Z catheters. Six 5-h in vitro studies were performed similarly at a depth of 9.0 cm (6.6 mmHg). Eight 15-min studies and nine 8-h in vivo studies were performed with healthy participants. Two correction methods - thermal compensation (TC) and interpolated thermal compensation (ITC) - were tested.

KEY RESULTS

Overall pressure drift varied both between studies (p < 0.01) and within sensors (p < 0.01). Drift resulted from thermal shock, an initial pressure change at intubation, and baseline drift, a linear drift over time (R(2)  > 0.96). Contrary to previous reports, there was no correlation between drift and average (r = -0.02) or maximum pressure exposure (r = -0.05). Following data correction, ITC had the lowest median error but persisted with a maximum error of 2.5 mmHg (IQR = 3.0).

CONCLUSIONS & INFERENCES

The substantial drift in the ManoScan(™) HRM system is highly variable and not corrected via the standard operating instructions. ITC has superior performance but requires communication with the manufacturer to enable this option. This has a substantial impact on clinical diagnosis, utility of existing normative data, and future research of HRM.

Diaphragmatic breathing for rumination syndrome: efficacy and mechanisms of action

BACKGROUND

While high resolution esophageal manometry combined with impedancometry has demonstrated that gastric pressurizations lead to rumination, the contribution of upper esophageal sphincter (UES) and esophagogastric junction (EGJ) function to rumination is unclear. Behavioral therapy with diaphragmatic breathing (DB) can reduce rumination. We aimed to evaluate the pressures in the stomach, EGJ and UES during rumination and the effects of DB augmented with biofeedback therapy.

METHODS

Sixteen patients with rumination were studied with manometry and impedancometry before and after a meal. The postprandial assessment comprised three periods: before, during, and after DB augmented with biofeedback therapy.

KEY RESULTS

All patients had postprandial rumination, which was associated (p < 0.001) with increased gastric pressure and reversal of the postprandial gastroesophageal pressure gradient from -4 (-43 to 18) before to 20 (7-79) mmHg during rumination. The EGJ pressure was lower (p < 0.001) during gastric pressurizations that were associated with rumination vs those that were not. The UES also relaxed, almost completely, during rumination. Patients had a median (range) of 5 (2-10) rumination episodes before, 1 (0-2) (p < 0.001) during, and 3 (1-5) after (p < 0.001 vs during) diaphragmatic breathing. During manometry and impedancometry, DB was well-tolerated and learned within 5 min. Diaphragmatic breathing increased EGJ pressure (p < 0.001) and restored a negative gastroesophageal pressure gradient (-20 mmHg [-80 to 7]).

CONCLUSIONS & INFERENCES

Diaphragmatic breathing aided with high resolution esophageal manometry is well-tolerated, effective and averts the gastroesophageal pressure disturbance that leads to rumination.

How to Perform and Interpret a High-resolution Anorectal Manometry Test

High-resolution anorectal manometry (HR-ARM) and high-definition anorectal manometry (HD-ARM) catheters have closely spaced water-perfused or solid state circumferentially-oriented pressure sensors that provide much better spatiotemporal pressurization than non-high resolution catheters. This is a comprehensive review of HR-ARM and HD-ARM anorectal manometry catheter systems, the methods for conducting, analyzing, and interpreting HR-ARM and HD-ARM, and a comparison of HR-ARM with non-high resolution anorectal manometry. Compared to non-high resolution techniques, HR-ARM and HD-ARM studies take less time and are easier to interpret. However, HR-ARM and HD-ARM catheters are more expensive and fragile and have a shorter lifespan. Further studies are needed to refine our understanding of normal values and to rigorously evaluate the incremental clinical utility of HR-ARM or HD-ARM compared to non-high resolution manometry.

Clinical Application of Esophageal High-resolution Manometry in the Diagnosis of Esophageal Motility Disorders

Esophageal high-resolution manometry (HRM) is replacing conventional manometry in the clinical evaluation of patients with esophageal symptoms, especially dysphagia. The introduction of HRM gave rise to new objective metrics and recognizable patterns of esophageal motor function, requiring a new classification scheme: the Chicago classification. HRM measurements are more detailed and more easily performed compared to conventional manometry. The visual presentation of acquired data improved the analysis and interpretation of esophageal motor function. This led to a more sensitive, accurate, and objective analysis of esophageal motility. In this review we discuss how HRM changed the way we define and categorize esophageal motility disorders. Moreover, we discuss the clinical applications of HRM for each esophageal motility disorder separately.

The use of colonic and anorectal high-resolution manometry and its place in clinical work and in research

BACKGROUND

In the esophagus, high-resolution manometry (HRM) has become a standard diagnostic tool in the investigation of suspected motility disorders. However, at the opposite end of the digestive tract (i.e., the colon and anorectum), the use of HRM still remains in its infancy, with relatively few published studies in the scientific literature. Further, the clinical utility of those studies that have been performed is largely undetermined.

PURPOSE

This review assesses all of the HRM studies published to date from both the colon and anorectum, explores the catheter types used, and attempts to determine the worth of HRM over traditional 'low-resolution' recordings from the same regions. Ultimately, this review addresses whether HRM currently provides information that will benefit patient diagnosis and treatment.