24-hour monitoring of transient lower esophageal sphincter relaxation events by long-term high-resolution impedance manometry in normal volunteers: The "mirror phenomenon"

Efficacy of Baclofen as Add-on Therapy for Refractory Gastroesophageal Reflux Disease: A Meta-analysis

OBJECTIVES

As a GABAB receptor agonist, baclofen has demonstrated efficacy in alleviating symptoms of refractory gastroesophageal reflux disease (r-GERD). This meta-analysis aims to evaluate the safety and effectiveness of baclofen as an add-on therapy for this condition.

METHOD

We conducted a comprehensive search of the PubMed, Embase, and Web of Science databases for studies published up until October 2023. Subsequently, we performed a meta-analysis encompassing all eligible trials.

RESULTS

From 719 records, 10 studies were included, most of these studies were moderate risk. The findings demonstrated that the addition of baclofen as a supplementary treatment effectively improves symptoms (GERD Q score) in r-GERD (standardized mean difference=-0.78, 95% CI: -1.06 to -0.51, I2=0%). The addition of this treatment also resulted in a decrease in the frequency of nonacidic reflux episodes (standardized mean difference=-0.93, 95% CI: -1.49 to -0.37, I2=63%) and an improvement in DeMeester scores (standardized mean difference=-0.82, 95% CI: -1.61 to -0.04, I2=81%) among patients with r-GERD when compared with the use of proton pump inhibitor (PPI) drugs alone. However, no significant disparity was observed in terms of reducing acid reflux episodes (standardized mean difference=-0.12, 95% CI: -0.49 to 0.19, I2=0%) and proximal reflux (standardized mean difference=-0.47, 95% CI: -1.08 to 0.14, I2=60%).

CONCLUSION

Baclofen as an add-on treatment can effectively improve the symptoms of patients with r-GERD and reduce the incidence of nonacidic reflux and improve DeMeester score. However, long-term use of baclofen leads to an increased incidence of side effects and is not effective in reducing the occurrence of acid reflux.

A Comparative Assessment of the Diagnosis of Swallowing Impairment and Gastroesophageal Reflux in Canines and Humans

Swallowing impairment is a highly prevalent and clinically significant problem affecting people and dogs. There are myriad causes of swallowing impairment of which gastroesophageal reflux is the most common in both species. Similarities in anatomy and physiology between humans and canines results in analogous swallowing disorders including cricopharyngeus muscle achalasia, esophageal achalasia, hiatal herniation, and gastroesophageal reflux with secondary esophagitis and esophageal dysmotility. Accordingly, the diagnostic approach to human and canine patients with swallowing impairment is similar. Diagnostic procedures such as swallowing fluoroscopy, high-resolution manometry, pH/impedance monitoring, and endolumenal functional luminal imaging probe can be performed in both species; however, nasofacial conformation, increased esophageal length, and the difficulty of completing several of these procedures in awake dogs are inherent challenges that need to be considered. Human patients can convey their symptoms and respond to verbal cues, whereas veterinarians must rely on clinical histories narrated by pet owners followed by comprehensive physical examination and observation of the animal eating different food consistencies and drinking water. Dogs may also be unwilling to drink or eat in the hospital setting and may be resistant to physical restraint during diagnostic procedures. Despite the species differences and diagnostic challenges, dogs are a natural animal model for many oropharyngeal and esophageal disorders affecting people, which presents a tremendous opportunity for shared learnings. This manuscript reviews the comparative aspects of esophageal anatomy and physiology between humans and canines, summarizes the diagnostic assessment of swallowing impairment in both species, and discusses future considerations for collaborative medicine and translational research.

The mechanisms associated with reflux episodes in ambulant subjects with gastro-esophageal reflux disease

BACKGROUND

The mechanisms associated with gastro-esophageal reflux (GER) episodes were studied using combined High-resolution Impedance Manometry (HRIM) and pH monitoring in ambulant subjects with different patterns of GERD.

METHODS

Sixteen subjects with mild-moderate esophagitis (Los Angeles (LA) grade A&B) (group A) and 11 subjects with severe esophagitis (LA grade C&D) or Barrett's esophagus (BE) were studied before and after a meal, resting, while walking, and during standardized exercise, using a HRIM and a pH probe.

KEY RESULTS

Post-prandial acid GER episodes were more common in group B (median 10 range (3-18) vs A (6.5 (0-18), p = 0.048). Postprandial acid clearance time was much longer in group B (median 0.71( 0.07-2.66 min) vs A (0.17 (0.04-2.44 min), p = 0.02). Transient lower esophageal sphincter relaxation (TLESR) was the most frequent mechanism associated with GER episodes in both groups. Post-prandial TLESRs with GER were more common in group B (median 17 (9-24) vs A 13.5 (7-34), p = 0.014), particularly during exercise (B 8 (6-9) vs A 6 (5-6.8), p = 0.007). Post-prandially TLESR with acid reflux increased during exercise in both groups (A rest median 2.4 (0-6.4) per hour vs exercise 4.7 (0-17.3), p = 0.005 and B 4 (0.8-9.6) vs 5.3 (2.7-13.3) per hour, p = 0.045).

CONCLUSIONS AND INFERENCES

TLESR was the most common mechanism associated with reflux episodes in all subjects. Acid reflux episodes were more common in subjects with severe esophagitis or BE and esophageal acid clearance was much slower. Post-prandial exercise increased TLESR with acid reflux and GERD patients should be encouraged to avoid exercise immediately after a meal.

Characterization of esophageal motor activity, gastroesophageal reflux, and evaluation of prokinetic effectiveness in mechanically ventilated critically ill patients: a high-resolution impedance manometry study

BACKGROUND

Motility disorders of upper gastrointestinal tract are common in critical illness and associated with significant clinical consequences. However, detailed quantitative and qualitative analyses of esophageal motor functions are lacking. Therefore, we aimed to characterize the key features of esophageal motility functions using high-resolution impedance manometry (HRIM) and to evaluate an objective link between esophageal motor patterns, gastric emptying, and gastroesophageal reflux. We also studied the prokinetic effects of metoclopramide.

METHODS

We prospectively performed HRIM for 16 critically ill hemodynamically stable patients. Patients were included if they had low gastric volume (LGV; < 100 mL/24 h, n = 8) or high gastric volume (HGV; > 500 mL/24 h, n = 8). The HRIM data were collected for 5 h with intravenous metoclopramide administration (10 mg) after the first 2 h.

RESULTS

The findings were grossly abnormal for all critically ill patients. The esophageal contraction vigor was markedly increased, indicating prevailing hypercontractile esophagus. Ineffective propulsive force was observed for 73% of esophageal activities. Panesophageal pressurization was the most common pressurization pattern (64%). Gastroesophageal reflux predominantly occurred with transient lower esophageal sphincter relaxation. The common features of the LGV group were a hyperreactive pattern, esophagogastric outflow obstruction, and frequent reflux. Ineffective motility with reduced lower esophageal sphincter tone, and paradoxically fewer reflux episodes, was common in the HGV group. Metoclopramide administration reduced the number of esophageal activities but did not affect the number of reflux episodes in either group.

CONCLUSION

All critically ill patients had major esophageal motility abnormalities, and motility patterns varied according to gastric emptying status. Well-preserved gastric emptying and maintained esophagogastric barrier functions did not eliminate reflux. Metoclopramide failed to reduce the number of reflux episodes regardless of gastric emptying status. Trial registration ISRCTN, ISRCTN14399966. Registered 3.9.2020, retrospectively registered. https://www.isrctn.com/ISRCTN14399966 .

Evaluation of the Esophagogastric Junction on High Resolution Manometry

The esophagogastric junction (EGJ) is a complex barrier between the thoracic and abdominal luminal gut compartments, comprised primarily of the lower esophageal sphincter (LES) and crural diaphragm. Although closed at rest, the EGJ relaxes to allow antegrade bolus transit and retrograde venting of air. Abnormal relaxation is the hallmark of achalasia spectrum disorders, while increased frequency of transient lower esophageal sphincter relaxations and/or EGJ disruption are seen in gastroesophageal reflux disease. High resolution manometry (HRM) is the modern day gold standard for assessment of EGJ morphology and function, with better performance characteristics compared with endoscopy and barium esophagography. Conventional LES metrics defining EGJ function include resting LES pressure as well as postswallow residual pressures. Newer HRM-based metrics include EGJ contractile integral, which measures static barrier function at rest, and EGJ morphology, which characterizes the relationship between LES and crural diaphragm. Provocative maneuvers assess dynamic EGJ function during physiological or pharmacologic stress. The most useful of these maneuvers, the rapid drink challenge, assesses for latent obstruction, while multiple rapid swallows evaluate adequacy of deglutitive inhibition. Amyl nitrate and cholecystokinin administration can segregate motor from structural obstruction. Newer provocative tests (straight leg raise maneuver, abdominal compression) and novel diagnostic tools (functional lumen imaging probe) complement HRM evaluation of the EGJ. Although current HRM metrics and maneuvers show promise in identifying clinically relevant EGJ abnormalities, future investigations evaluating management outcomes will improve segregation of normal from abnormal EGJ morphology and function.

Enhancing High-Resolution Esophageal Manometry: Use of Ancillary Techniques and Maneuvers

High-resolution manometry evaluates esophageal motor function using 10 supine water swallows. Superimposing impedance over high-resolution manometry pressure topography assesses the relationship between contraction and bolus propulsion and identifies inadequate clearance. Ancillary techniques and maneuvers augment the standard supine high-resolution manometry evaluation by challenging peristaltic function. Increasing bolus volume (rapid drink challenge) and altering bolus consistency (standardized test meal, solid swallows) enhance identification of esophageal outflow obstruction syndromes. Physiologic maneuvers (multiple rapid swallows, abdominal compression) address the ability of the esophageal smooth muscle to augment contraction vigor. Pharmacologic challenge is less commonly used clinically, and elucidates pathophysiology of esophageal motor disorders.