High-Resolution Pharyngeal Manometry and Impedance: Protocols and Metrics-Recommendations of a High-Resolution Pharyngeal Manometry International Working Group

Effects of Pyridostigmine on Esophageal and Pharyngeal Motility in Dysphagic Patients Undergoing High-Resolution Manometry

Weak or absent peristalsis of the esophageal musculature is a common finding in ambulatory patients suffering from dysphagia and frequently associated with gastroesophageal reflux. There is currently no pharmacologic intervention that reliably improves esophageal contractility in patients suffering from various esophageal motility disorders. Our objective was to evaluate the acute effects of pyridostigmine on high-resolution manometry parameters in patients suffering from dysphagia with evidence of esophageal dysmotility. Pyridostigmine is an acetylcholinesterase inhibitor which increases effective concentrations of acetylcholine at the neuromuscular junction of both striated and smooth muscle cells. We conducted a prospective crossover study of five patients with dysphagia and proven esophageal dysmotility. Three patients had baseline ineffective esophageal motility and two had achalasia. Patients underwent pharyngeal and esophageal manometry before and after pyridostigmine administration. The median distal contractile integral (DCI), a marker of esophageal contractile vigor, was significantly higher post pyridostigmine administration 3001 (1950.3-3703.2) mmHg × s × cm compared to pre-pyridostigmine DCI of 1229.9 (956.2-2100) mmHg × s × cm; P < 0.001. Pre-pyridostigmine 18/25 (72%) of the patient's swallows was peristaltic compared to 25/25 (100%) post-pyridostigmine; P < 0.005. No other pharyngeal or esophageal high-resolution manometry parameter differed significantly after pyridostigmine administration. The results of this pilot study demonstrate that pyridostigmine acutely improves esophageal contractile vigor in patients suffering from dysphagia with esophageal dysmotility. Further investigation with larger sample size, longer follow-up, side effect profile, and patient-reported outcome measures is still needed to determine the clinical usefulness of pyridostigmine in specific disorders of esophageal motility.

Effect of Tongue-Hold Swallow on Pharyngeal Contractile Properties in Healthy Individuals

Tongue-hold swallow (THS) is a swallow exercise in which an individual swallows saliva while holding the anterior portion of the tongue between the front teeth. The effect of THS on pharyngeal contractile vigor is still unclear. The purpose of this study was to quantify THS using high-resolution manometry with a contractile integral analysis. Twenty-two healthy participants performed three different saliva swallow tasks: normal swallow, weak THS (in which the tongue was protruded 1 cm outside the upper incisors), and strong THS (in which the tongue was protruded 2 cm outside the upper incisors). The participants repeated each task twice randomly. Pharyngeal and upper esophageal sphincter metrics, including the pharyngeal contractile integral, were analyzed. Both weak and strong THS enhanced the velopharyngeal contractile integral and peak pressure compared with normal swallow (P < 0.01). THS also prolonged mesopharyngeal contraction (P < 0.01). Holding the tongue anteriorly during swallow requires significant biomechanical changes to pharyngeal contractile properties at the superior and middle pharyngeal constrictor levels; thus, it may serve as a resistance exercise for the muscles that are involved in bolus propulsion.

Biomechanical correlates of sequential drinking behavior in aging

BACKGROUND

The timed water swallow test (TWST) is a test of sequential swallowing where a measured volume is ingested as quickly as comfortably possible. We undertook a study of the biomechanics underpinning the TWST in healthy young and older participants.

METHODS

Thirty healthy volunteers underwent high-resolution impedance manometry (MMS; Unisensor, 2.7 mm diameter, 32 pressure sensors, 16 impedance segments). Participants were asked to drink 150 mL, 0.9% normal saline solution rapidly. Swallowing biomechanics and bolus flow characteristics were assessed using pressure-flow analysis and compared using t test and Fisher's exact test with significance as P < .05.

KEY RESULTS

Older participants (n = 18; 76 ± 11 years) took longer to complete the TWST (21.2 ± 2.5 vs 9.2 ± 1.0 seconds; P < .001) and displayed reduced volume per swallow (16.6 ± 1.3 vs 27.8 ± 2.9 mL; P < .001) compared to younger participants (n = 12; 29 ± 5 years). Two distinctive pharyngeal swallowing patterns were observed: (a) a single rapid sequence of swallows with or without a clearing swallow (Pattern I) or (b) multiple, shorter sequences interrupted and/or interspersed with single swallows or breaks (Pattern II). Some older participants showed biomechanical evidence of upper esophageal sphincter restriction (n = 7) or impaired deglutitive inhibition (n = 7), associated with the more prolonged Pattern II (TWST duration 30.1 ± 1.5 vs Pattern I 11.9 ± 1.5 seconds; P < .001).

CONCLUSIONS AND INFERENCES

Healthy older participants had an increased duration of TWST, suggesting a need to adapt normative values for this population. Rapid sequential swallowing was associated with evidence of UES restriction and impaired deglutitive inhibition in some older participants.

Modulation of pharyngeal swallowing by bolus volume and viscosity

Oropharyngeal swallowing involves complex neuromodulation to accommodate changing bolus characteristics. The pressure events during deglutitive pharyngeal reconfiguration and bolus flow can be assessed quantitatively using high-resolution pharyngeal manometry with impedance. An 8-French solid-state unidirectional catheter (32 pressure sensors, 16 impedance segments) was used to acquire triplicate swallows of 3 to 20 ml across three viscosity levels using a Standardized Bolus Medium (SBMkit) product (Trisco, Pty. Ltd., Australia). An online platform (https://swallowgateway.com/; Flinders University, South Australia) was used to semiautomate swallow analysis. Fifty healthy adults (29 females, 21 males; mean age 46 yr; age range 19-78 yr old) were studied. Hypopharyngeal intrabolus pressure, upper esophageal sphincter (UES) maximum admittance, UES relaxation pressure, and UES relaxation time revealed the most significant modulation effects to bolus volume and viscosity. Pharyngeal contractility and UES postswallow pressures elevated as bolus volumes increased. Bolus viscosity augmented UES preopening pressure only. We describe the swallow modulatory effects with quantitative methods in line with a core outcome set of metrics and a unified analysis system for broad reference that contributes to diagnostic frameworks for oropharyngeal dysphagia.NEW & NOTEWORTHY The neuromodulation of the healthy oropharyngeal swallow response was described in relation to bolus volume and viscosity challenges, using intraluminal pressure and impedance topography methods. Among a wide range of physiological measures, those indicative of distension pressure, luminal opening, and flow timing were most significantly altered by bolus condition, and therefore can be considered to be potential markers of swallow neuromodulation. The study methods and associated findings inform a diagnostic framework for swallow assessment in patients with oropharyngeal dysphagia.

Post-stroke Dysphagia: Recent Insights and Unanswered Questions

PURPOSE OF REVIEW

We explored themes in recent post-stroke dysphagia literature, focusing on the following questions: (1) What does post-stroke dysphagia look like?; (2) Who gets post-stroke dysphagia?; (3) What are the consequences of post-stroke dysphagia?; and (4) How can we improve treatment of post-stroke dysphagia?

RECENT FINDINGS

There have been several improvements in quantitative descriptions of swallowing physiology using standard and new evaluation techniques. These descriptions have been correlated with lesion locations, and several factors can predict development of post-stroke dysphagia and its sequelae. Novel treatment paradigms have leveraged post-stroke neuroplastic improvements using neurostimulation and biofeedback techniques. Despite recent findings, the field is limited by lack of standardization and unanswered questions on rehabilitation variables. Our improved understanding of post-stroke dysphagia will enhance our ability to prevent, identify, and treat it. Future work should be grounded in swallowing physiology and continue refining treatments, particularly in the acute stage.

Characterizing the proximal esophageal segment in patients with symptoms of esophageal dysmotility

BACKGROUND

Proximal esophageal striated muscle contractility may be abnormal in patients with esophageal symptoms, but is not assessed in the Chicago Classification (CC) v3.0. We aimed to (a) determine the prevalence of abnormal proximal esophageal contractility in patients with esophageal symptoms; (b) compare proximal esophageal contractility in patients with different esophageal motility disorders; (c) assess the association of abnormal proximal esophageal contractility with esophageal symptoms.

METHODS

Patients undergoing high-resolution esophageal manometry (HREM) from 7/2019 to 11/2019 and healthy volunteers (HVs) were studied. Measurements of the proximal esophageal segment included the vigor of contractility of the proximal esophagus (proximal contractile integral/PCI). Patients rated gastrointestinal symptoms' severity.

KEY RESULTS

HREM was performed on 221 patients (63.8% females, mean age 57.1 ± 1.1 years) and 19 HVs. Mean PCI in HVs was 299.5 ± 30.6 (95% CI 32.3-566.7 mm Hg^. s^. cm). Of all patients, 61 (27.6%) had abnormal PCI. HVs and patients with different esophageal motility disorders had significantly different PCI (P < .01). Type 1 achalasia patients had weaker PCI than patients with absent contractility (P = .02). Patients with abnormal PCI had more severe dysphagia (P = .02), nausea (P = .03), vomiting (P = .03), and lower bolus clearance (P < .01) than patients with normal PCI.

CONCLUSIONS AND INFERENCES

Abnormal PCI was found in a fourth of patients with esophageal symptoms. PCI may be useful to distinguish some esophageal motility disorders. Patients with abnormal PCI had a higher severity of some upper gastrointestinal symptoms than patients with normal PCI. Assessing the proximal esophageal segment on HREM may be useful in characterizing patients with esophageal symptoms.

The use of impedance planimetry (Endoscopic Functional Lumen Imaging Probe, EndoFLIP® ) in the gastrointestinal tract: A systematic review

BACKGROUND AND PURPOSE

The EndoFLIP® system is a method of delineating impedance and was first designed to investigate the characteristics of the esophago-gastric junction. In the last decade, its use was widened to investigate other sphincteric and non-sphincteric systems of the gastrointestinal tract. The objective of the present systematic review was to summarize the available data in literature on the use of the EndoFLIP® system in the gastrointestinal tract, including sphincteric and non-sphincteric regions. We performed a systematic review in accordance with recommendations for systematic review using PRISMA guidelines without date restriction, until June 2020, using MEDLINE-PubMed, Cochrane Library, and Google Scholar databases. Only articles written in English were included in the present review. Five hundred and six unique citations were identified from all database combined. Of those, 95 met the inclusion criteria. There was a lack of standardization among studies in terms of anesthetic drugs use, probe placement, and inflation protocol. In most cases, only small cohorts of patients were included. Most studies investigated the EGJ, with a potential use of the EndoFLIP® to identify a subgroup of patients with achalasia and for intraoperative assessment of treatment efficacy in achalasia. However, the use of EndoFLIP® in the esophageal body (esophageal panometry), other esophageal diseases (gastro-esophageal reflux disease, eosinophilic esophagitis), and other sphincter regions (anal canal, pylorus) will need further confirmatory studies. The EndoFLIP® system provides detailed geometric data of the gastrointestinal lumen but further works are needed to determine its use in clinical practice.

Aspects of the assessment and management of pharyngoesophageal dysphagia

Swallowing complaints are common and may have significant consequences for nutrition and pulmonary health. Etiology varies and different aspects of the deglutitive system may be affected. A thorough assessment from the oral cavity to the stomach will provide physiologic information that enables specific targeted management plans to be devised. Although the swallow trajectory bridges anatomic areas, there has previously been a tendency to compartmentalize assessment and treatment by arbitrary anatomic boundaries. It is now clear that this approach fails to appreciate the complexity of swallow mechanics and that systems (oral, pharyngeal, esophageal, and pulmonary) are intertwined and codependent. Swallowing specialists from different backgrounds and with complementary skill sets form a multidisciplinary team that can provide insight and address multiple areas of management. With the advent of new tools for instrumental evaluation, such as manometry, targeted rehabilitative strategies can be informed by physiology, increased in precision and breadth, and assessed quantitatively. Surgical approaches have evolved toward endoscopic techniques, and food technology is expanding options in dietary management. The multidisciplinary team is core to managing this varied and often neglected patient population. This review is for clinicians treating swallowing disorders and will explore the selected aspects of the assessment and management of pharyngoesophageal swallowing disorders.

Perceived Professional and Institutional Factors Influencing Clinical Adoption of Pharyngeal High-Resolution Manometry

Purpose We assessed experienced clinicians' perceptions of benefits and drawbacks to the clinical adoption of pharyngeal high-resolution manometry (HRM). This article focuses on the professional and institutional factors that influence the clinical adoption of pharyngeal HRM by speech-language pathologists (SLPs). Method Two surveys (closed- and open-ended questions) and a series of focus groups were completed with SLP members of both the American Speech-Language-Hearing Association and the Dysphagia Research Society (DRS). Transcripts were inductively coded for emergent themes. Results Thirteen SLPs were recruited to attend focus group sessions at the American Speech-Language-Hearing Association. Eighty-seven SLPs responded to the DRS open-set response survey. Two additional focus groups of 11 SLPs were convened at the DRS meeting. Conventional content analysis revealed overall SLP enthusiasm for the clinical use of HRM, with some concerns about the technology adoption process. The following themes related to the professional and institutional factors influencing clinical adoption were identified: (a) scope of practice, (b) access, (c) clinical workflow, and (d) reimbursement. Conclusion These data serve to elucidate the most salient factors relating to the clinical adoption of pharyngeal HRM into routine speech-language pathology clinical practice. While enthusiasm exists, a variety of systems-level issues must be addressed to support this process.

Best Practices in Modified Barium Swallow Studies

Purpose The modified barium swallow study (MBSS) is a widely used videofluoroscopic evaluation of the functional anatomy and physiology of swallowing that permits visualization of bolus flow throughout the upper aerodigestive tract in real time. The information gained from the examination is critical for identifying and distinguishing the type and severity of swallowing impairment, determining the safety of oral intake, testing the effect of evidence-based frontline interventions, and formulating oral intake recommendations and treatment planning. The goal of this review article is to provide the state of the science and best practices related to MBSS. Method State of the science and best practices for MBSS are reviewed from the perspectives of speech-language pathologists (SLPs) and radiologists who clinically practice and conduct research in this area. Current quandaries and emerging clinical and research trends are also considered. Results This document provides an overview of the MBSS and standards for conducting, interpreting, and reporting the exam; the SLPs' and radiologist's perspectives on standardization of the exam; radiation exposure; technical parameters for recording and reviewing the exam; the importance of an interdisciplinary approach with engaged radiologists and SLPs; and special considerations for examinations in children. Conclusions The MBSS is the primary swallowing examination that permits visualization of bolus flow and swallowing movement throughout the upper aerodigestive tract in real time. The clinical validity of the study has been established when conducted using reproducible and validated protocols and metrics applied according to best practices to provide accurate and reliable information necessary to direct treatment planning and limit radiation exposure. Standards and quandaries discussed in this review article, as well as references, provide a basis for understanding the current best practices for MBSS.

Swallowing in Obese Individuals before and after Bariatric Surgery

PURPOSE

To evaluate the oral and pharyngeal phases of swallowing in obese patients before and after bariatric surgery.

MATERIAL AND METHOD

Swallowing was evaluated by videofluoroscopy before and after 80 to 123 days from bariatric surgery in 19 individuals with obesity (15 women), aged 25-60 years. The body mass index (BMI) before surgery was from 40.1 to 57.0 kg/m². The surgical treatment was performed with laparoscopic Roux-en-Y gastric by-pass (RYGB). After surgery, the BMI ranged from 31.7 to 48.4 kg/m². The control group had 19 healthy volunteers (15 women), aged 22-56 years and BMI from 19.4 to 29.7 kg/m². Swallowing was evaluated with swallows of 5 mL of liquid and paste boluses in triplicate, and a solid bolus in duplicate.

RESULTS

With swallowing of liquid bolus, individuals with obesity had, before and after surgery, an increased frequency of premature posterior spillage. Before the surgery, the obese subjects had longer pharyngeal clearance of liquid compared with the control group and with individuals after the surgery. After the surgery, obese individuals had longer duration of the hyoid movement with liquid and paste boluses, compared with before surgery. Also, there was a reduction of the interval between the bolus entering the phaynx and the onset of upward hyoid excursion.

CONCLUSION

Non-operated obese patients had a longer pharyngeal clearance for liquid bolus compared with healthy controls. After bariatric surgery, there was an increase in hyoid movement duration.

Swallowing Pressure Variability as a Function of Pharyngeal Region, Bolus Volume, Age, and Sex

OBJECTIVES

Within-individual movement variability occurs in most motor domains. However, it is unknown how pharyngeal swallowing pressure varies in healthy individuals. We hypothesized that: 1) variability would differ among pharyngeal regions; 2) variability would decrease with increased bolus volume; 3) variability would increase with age; and 4) there would be no sex differences.

STUDY DESIGN

Case series.

METHODS

We used pharyngeal high-resolution manometry to measure swallowing pressure in the following regions: velopharynx, tongue base, hypopharynx, and upper esophageal sphincter. Data were collected from 97 healthy adults (41 male) aged 21 to 89 years during thin liquid swallows: 2 mL, 10 mL, and participant-selected comfortable volume. Pressure variability was measured using coefficient of variation. Repeated measures analysis of variance was used to assess impacts of region, bolus volume, age, and sex on pressure variability.

RESULTS

There was a significant region × volume interaction (P < .001) and significant main effect of age (P = .005). Pressures in the hypopharynx region were more variable than all other regions (P ≤ .028), and pressures in the tongue base region were less variable than all other regions (P ≤ .002) except at 2 mL volumes (P = .065). Swallowing pressure variability was significantly different in the velopharynx and upper esophageal sphincter regions, with comfortable volume and 2 mL swallows having greater variability than 10 mL swallows (P ≤ .026). Pressure variability significantly increased with increasing age (P = .002). There were no effects of sex on pressure variability (P ≥ .15).

CONCLUSION

Pharyngeal swallowing pressure variability differs according pharyngeal region, volume, and age but not sex. Abnormal swallowing pressure variability may reflect deviations in motor control in persons with swallowing impairment, and results from this study can be used as normative data for future investigations evaluating swallowing pressure generation.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E52-E58, 2021.