Mechanisms of gastro-oesophageal reflux in the lateral decubitus positions

Unveiling the intricacies: Insight into gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) poses a substantial global health challenge, with prevalence rates exhibiting geographical variation. Despite its widespread recognition, the exact prevalence and associated risk factors remain elusive. This article comprehensively analyzed the global burden of GERD, shedding light on its risk factors, underlying pathophysiological mechanisms, current diagnostic modalities, evolving management strategies tailored to diverse patient profiles, and complex determinants contributing to treatment failures. A deeper comprehension of GERD is achieved by dissecting these intricate facets, paving the way for enhanced clinical management and improved patient outcomes.

Comparison of left versus right lateral starting position on colonoscopy: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Modifying patient position during colonoscopy has been proposed as a simple and inexpensive technique to increase luminal distention and improve navigation through the large bowel. The left lateral (LL) decubitus starting position is commonly used during colonoscopy. However, reports indicate that other starting positions may offer additional benefit. We aimed to determine if the right lateral (RL) starting position compared to the standard LL starting position could improve outcomes in colonoscopy.

METHODS

We searched PubMed, Medline, and EMBASE through June 2020 to identify studies comparing RL and LL starting positions during colonoscopy. The primary outcomes included mean cecal insertion time and cecal intubation rate, and adverse events were assessed by pooling data using a random-effects model expressed in terms of odds ratio (OR), mean difference, and 95% confidence interval (CI).

RESULTS

We identified 5 randomized controlled trials, including 809 participants, that compared LL vs. RL colonoscopy. The pooled OR for cecal intubation rate was 1.3 (95%CI 0.8-2.3; P=0.3). The mean difference in mean cecal insertion time was 0.08 (95%CI -0.09 to 0.26; P=0.4). Heterogeneity between studies was low (I 2=0%). No complications were reported in either arm of the study. Pain scores assessed using a visual analog scale were comparable among both arms of the study.

CONCLUSION

The RL starting position for colonoscopy was comparable to the LL and offered no additional benefit in terms of cecal intubation time, intubation rate, or patient discomfort.

The Influences of Visceral Fat Area on the Sites of Esophageal Mucosal Breaks in Subjects with Gastroesophageal Reflux Diseases

Background

Central obesity is suggested as a risk factor for gastroesophageal reflux diseases. The aim of this study was to evaluate the influences of a visceral fat area on the site of mucosal breaks in the esophagogastric junction (EGJ).

Methods

Subjects who underwent abdomen-computerized tomography and esophagogastroduodenoscopy for screening on the same day were evaluated between 2007 and 2016. We enrolled 178 subjects who had erosive esophagitis (LA classifications A-D). Abdominal obesity was evaluated by measuring visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), VAT-to-SAT ratio, total adipose tissue (TAT), body mass index (BMI), and waist circumference (WC).

Results

The lesser curvature (LC) of EGJ was the most frequent site of mucosal breaks (104 cases, 58.4%). BMI, WC, VAT, the VAT-to-SAT ratio, and TAT were higher in the LC group. In multivariate analysis, higher VAT (odds ratio (OR) 2.90, 95% confidence interval (CI) 1.18 to 7.13, 3rd vs. 1st quartile, P = 0.021; OR 3.63, 95% CI 1.44 to 9.10, 4th vs. 1st quartile, P = 0.006) and the VAT/SAT ratio (OR 2.91, 95% CI 1.11 to 7.61, 3rd vs. 1st quartile, P = 0.03; OR 3.02, 95% CI 1.17 to 7.83, 4th vs. 1st quartile, P = 0.023) were significantly associated with mucosal breaks in the LC group. However, BMI, WC, and TAT were not significant in the multivariate analysis.

Conclusion

The VAT and the VAT/SAT ratio were significantly associated with the mucosal breaks in the LC of EGJ. Visceral obesity could influence the location of the mucosal breaks on EGJ.

Lifestyle measures in the management of gastro-oesophageal reflux disease: clinical and pathophysiological considerations

Several lifestyle and dietary factors are commonly cited as risk factors for gastro-oesophageal reflux disease (GORD) and modification of these factors has been advocated as first-line measures for the management of GORD. We performed a systematic review of the literature from 2005 to the present relating to the effect of these factors and their modification on GORD symptoms, physiological parameters of reflux as well as endoscopic appearances. Conflicting results existed for the association between smoking, alcohol and various dietary factors in the development of GORD. These equivocal findings are partly due to methodology problems. There is recent good evidence that weight reduction and smoking cessation are beneficial in reducing GORD symptoms. Clinical and physiological studies also suggest that some physical measures as well as modification of meal size and timing can also be beneficial. However, there is limited evidence for the role of avoiding alcohol and certain dietary ingredients including carbonated drinks, caffeine, fat, spicy foods, chocolate and mint.

Effect of lateral positioning on gastroesophageal reflux (GER) and underlying mechanisms in GER disease (GERD) patients and healthy controls

BACKGROUND

Posture has been shown to influence the number of transient lower esophageal sphincter relaxation (TLESRs) and gastroesophageal reflux (GER), however, the physiology explaining the influence of right lateral position (RLP), and left lateral position (LLP) is not clear. The aim of this study was to determine the influence of RLP and LLP on TLESRs and GERD after a meal in GER disease (GERD) patients and healthy controls (HC) while monitoring gastric distension and emptying.

METHODS

Ten GERD patients and 10 HC were studied for 90 min (30 min test meal infusion, 30 min postprandial in either RLP or LLP (randomly assigned) and 30 min in alternate position). The study was repeated on a separate day in reverse position order. TLESRs, GER, and gastric emptying rate were recorded using manometry, multichannel intraluminal impedance, and (13) C-octanoate breath tests. Gastric distension was visualized by five serial gastric volume scintigraphy scans during the first 30 min.

KEY RESULTS

Gastroesophageal reflux, (GER) disease patients had increased numbers of TLESRs in RLP compared to LLP in the first postprandial hour [5 (4-14) and 4.5 (2-6), respectively, P = 0.046] whereas the number of TLESRs was not different in RLP and LLP [4 (2-4) and 4 (3-6), respectively, P = 0.7] in HC. Numbers of GER increased similar to TLESRs in GERD patients. In GERD patients, gastric emptying reached peak (13)CO(2) excretion faster and proximal gastric distension was more pronounced.

CONCLUSIONS & INFERENCES

In GERD patients, TLESRs, GER, distension of proximal stomach, and gastric emptying are increased in RLP compared to LLP. This effect is not seen in HC.

Impedance monitoring shows that posture and a meal influence gastro-oesophageal reflux composition and frequency

Impedance monitoring determines reflux composition as liquid and/or gas, and we assess with impedance the effect of posture and a meal on reflux composition. Twenty-nine gastro-oesophageal reflux disease (GORD) patients and 10 normal volunteers underwent simultaneous impedance, manometry and pH for three 40-min periods, each 20-min upright, 10-min left side and 10-min right side. One period was fasting, and two postprandial. We found that reflux event composition on the right side was liquid-only near exclusively (93%). In contrast, 85% of reflux on the left side and 74% upright was gas-only or liquid and gas (P < 0.001). More gas-only reflux occurred fasting (80%) than postprandial (P < 0.01). Reflux composition was similar in the study groups and two postprandial periods (P > 0.25). After confirming gas reflux suppression on the right side, a pilot study assessed gastric anatomy as a cause. Five achalasia patients had fluid injected into the stomach at endoscopy, and the EG junction was submerged below liquid-only on the right side. We conclude that reflux is nearly always liquid-only on the right side where the EG junction may be below fluid. Reflux fasting is usually gas-only. Different posture and fasting times may (i) explain variations in acid exposure during pH monitoring and (ii) promote or prevent GORD symptoms.

The effect of total and anterior partial fundoplication on antireflux mechanisms of the gastroesophageal junction

BACKGROUND

The effect of total (Nissen) and anterior partial fundoplication (APF) for the surgical treatment of gastroesophageal reflux disease (GERD) on the motor behavior of the esophagogastric axis has not been fully assessed. The purpose of this study was to assess any alterations in lower esophageal sphincter (LES) and gastric fundus motor parameters in GERD patients after Nissen or APF fundoplication.

METHODS

Twenty four patients with documented GERD underwent either laparoscopic Nissen fundoplication (n = 12) or laparoscopic APF (n = 12). Preoperative and postoperative stationary esophageal manometry included assessment of LES resting and postdeglutition relaxation pressures, intragastric pressure, and LES transient relaxations in the left lateral and upright positions and after gastric distension.

RESULTS

Both types of fundoplication resulted in significant increases in LES resting (P <0.001) and postdeglutition relaxation pressure (P <0.001) in both positions and after gastric distention. Intragastric pressure increased only after Nissen fundoplication in the postgastric distention state (P = 0.01). Transient LES relaxations were equally abolished after both procedures. All postoperative changes were to a similar level after either procedure with the exception of intragastric pressure after gastric distention, which was significantly higher after total than after partial fundoplication (P = 0.04).

CONCLUSIONS

Both procedures equally increase LES resting and postdeglutition relaxation pressures and abolish transient LES relaxations at all states. The significantly higher intragastric pressure at the postgastric distention state after Nissen fundoplication could possibly explain the higher incidence of epigastric fullness and discomfort after this type of antireflux surgery.

Transient lower esophageal sphincter relaxations are no more frequent in patients with gastroesophageal reflux disease than in asymptomatic volunteers

OBJECTIVES

Studies of the relative frequency of transient lower esophageal sphincter relaxations (TLESRs) in patients with gastroesophageal reflux disease and asymptomatic controls have revealed conflicting data. We have therefore studied the frequency of TLESRs and the frequency and mechanisms of acid reflux episodes in patients with gastroesophageal reflux disease and age- and sex-matched asymptomatic controls using standardized criteria.

METHODS

Ten patients with symptomatic gastroesophageal reflux disease (four male, aged 50 [30-59] yr) and 10 asymptomatic matched volunteers (four male, aged 50 [32-59] yr) were studied. Esophageal, lower esophageal sphincter, and gastric manometric and esophageal pH readings were recorded for 1 h before and 1 h after a 200-kcal, 150 ml long-chain triglyceride meal.

RESULTS

TLESR frequency increased after the meal in both volunteers (median 0 [range = 0-3] to 3 [0-8] per hour,p < 0.01) and patients (1 [0-6] to 2.5 [0-9] per hour, p = 0.08). There was no significant difference in the frequency of TLESRs between volunteers and patients. TLESRs were more likely to be associated with acid reflux in patients (65% vs 37%, p = 0.03), whereas volunteers were more likely to reflux gas or liquid without acid (30% vs 3.0%, p = 0.01).

CONCLUSIONS

TLESRs are no more frequent in patients with gastroesophageal reflux disease than age- and sex-matched asymptomatic volunteers. However, when TLESRs occur in patients, they are twice as likely to be associated with acid reflux.

Acid, nonacid, and gas reflux in patients with gastroesophageal reflux disease during ambulatory 24-hour pH-impedance recordings

BACKGROUND & AIMS

Gastroesophageal reflux can be acid, nonacid, pure liquid, or a mixture of gas and liquid. We investigated the prevalence of acid and nonacid reflux and the air-liquid composition of the refluxate in ambulant healthy subjects and patients with reflux disease (GERD).

METHODS

Twenty-four-hour ambulatory recordings were performed in 30 patients with symptomatic GERD and erosive esophagitis and in 28 controls. Esophageal pH and impedance were used to identify acid reflux (pH drop below 4.0), minor acid reflux (pH drop above 4.0), nonacid reflux (pH drop less than 1 unit + liquid reflux in impedance), and gas reflux.

RESULTS

The total rate of gastroesophageal reflux episodes was similar in patients and controls. Patients with GERD had a higher proportion (45% vs. 33%) and rate of acid reflux than controls (21.5 [9-35]/24 h vs. 13 [6.5-21]/24 h; P < 0.05). One third of reflux events was nonacid in both groups. Mixed reflux of gas and liquid was the most frequent pattern with gas preceding liquid in 50%-80% of cases. Pure liquid reflux was more often acid in patients with GERD than controls (45% vs. 32%; P < 0.05).

CONCLUSIONS

Reflux of gastric contents was similarly frequent in patients with GERD and controls. Although there was no difference in the overall number of reflux episodes, more acidic reflux occurred in symptomatic patients with GERD, suggesting differences in gastric acid secretion or distribution.

Effect of different recumbent positions on postprandial gastroesophageal reflux in normal subjects

OBJECTIVE

Gastroesophageal reflux (GER) is increased in the right compared to the left recumbent position. Esophageal acid exposure is related to the acidity at the cardia, but the effect of body position on the acidity at the cardia has not yet been investigated. We aimed to investigate the mechanisms underlying increased esophageal acid exposure in the right recumbent position.

METHODS

On 2 separate days a 4-h combined esophageal and lower esophageal sphincter (LES) manometry and pH recording of esophagus, gastric cardia, and corpus was performed in the right and left recumbent position after a high fat meal in 10 healthy subjects.

RESULTS

In the right recumbent position a prolonged esophageal acid exposure (7.0% vs 2.0%, p < 0.03), a higher incidence of reflux episodes (3.8 vs 0.9/h, p < 0.03), more transient LES relaxations (TLESRs) (6.5 vs 3.2/h, p < 0.03), and higher percentage TLESRs associated with reflux (57.0% vs 22.4% p < 0.03) was recorded than in the left supine position. Acidity at gastric cardia and corpus was not affected by body position.

CONCLUSIONS

Increased esophageal acid exposure in the right recumbent position relative to the left recumbent position is the result of a higher incidence of GER episodes caused by an increased incidence of TLESRs and higher percentage of TLESRs associated with GER. Body position does not affect the acidity at the gastric cardia and corpus.