Assessment of gastric accommodation: overview and evaluation of current methods

Transabdominal Ultrasound of the Stomach in Patients with Functional Dyspepsia: A Review

Background/Aim: Dyspepsia is a very common condition worldwide and has an immense impact on quality of life. Functional dyspepsia (FD) is defined by dyspeptic symptoms with the absence of any structural abnormality that can explain the cause. Ultrasonography (US) is a non-invasive imaging modality that can be applied to assess gastric function. The aim of this review paper is to assess how ultrasonography can sort out patients with dyspepsia and help diagnose functional dyspepsia. Methods: Using the keywords "functional dyspepsia" and "ultrasonography", the PubMed database was screened for publications on the use of ultrasonography to identify functional dyspepsia. Afterward, two screening processes were performed to narrow the articles down to a rational number. Results: A total of 169 articles were obtained from the literature search, and 31 of these were included after the screening process. Ultrasonography was capable of identifying functional dyspepsia pathophysiology using both two-dimensional (2D) and three-dimensional (3D) ultrasound. Conclusions: We conclude that ultrasonography is a non-invasive, safe, low-cost, and widely accessible method that can help diagnose functional dyspepsia through the exclusion of organic dyspepsia and assessing FD pathophysiology. Incorporation of ultrasound in the work-up of patients with functional dyspepsia allows for a sound diagnostic approach and can further improve patient management.

Extensive scintigraphic gastric motor function testing with concurrent symptom recording predicts prospectively measured daily dyspeptic symptoms

BACKGROUND

Absent "organic" disease, dyspeptic symptoms may arise from abnormal gastric sensation, accommodation, motility or emptying (GE). Extensive gastric sensorimotor evaluation is rarely undertaken because testing is prolonged, invasive, poorly tolerated or unavailable.

AIMS

To investigate whether gastric antral motor function, evaluated with scintigraphy, predicts GE. To explore whether motor testing with symptom recording predicts day-to-day symptoms in patients with dyspepsia.

METHODS

GE was determined using a scintigraphic solid-meal protocol (296 kcal, 35% fat). Antral motility was estimated from 10 min of scintigraphic time-activity curves acquired 40 min after meal consumption. An antral motility index (MI) was derived from contraction amplitude and frequency. Intra-gastric distribution of the meal on scintograms at 1 h (IGD1) was determined. Meal-induced symptoms were evaluated by questionnaire. Patients completed the Gastroparesis Cardinal Symptom Index Daily Diary (GCSI-DD) for 14 days.

RESULTS

Twelve healthy participants and 23 prospectively recruited patients completed the study. Nine patients had delayed, and 2 had rapid, GE. In univariate analysis MI explained 42% of GE half-time. In multivariate analysis MI and GE half-time explained 25% of the variance in meal-induced symptoms. While scintigraphic evaluation of gastric motor function with symptom recording explained 80% of the variance in the GCSI-DD, meal-induced symptoms were the only significant predictor. However, among patients with delayed GE, MI, GE half-time, IGD1, and meal-induced symptoms all significantly predicted GCSI-DD.

CONCLUSIONS

Antral motility predicts GE. In exploratory analyses, only meal-induced symptoms predicted daily symptoms among patients with dyspepsia. However, motor function also predicted symptoms in patients with delayed GE.

Clinical validation of the VIPUN™ gastric monitoring system versus manometry for the evaluation of gastric motility

BACKGROUND

Gastrointestinal dysmotility is frequently suspected in patients with gastroparesis, functional dyspepsia, and ileus, and in the intensive care unit. Monitoring of gastric motility in clinical practice remains challenging. A novel technology was developed to meet the medical need for a widely available bedside tool to monitor gastric motility continuously. The VIPUN™ Gastric Monitoring System (GMS) comprises a nasogastric feeding tube with intragastric balloon to allow for measuring gastric contractions.

AIMS

To compare the performance of the VIPUN GMS versus a reference technique (manometry).

METHODS

In this validation study in healthy subjects, the investigational catheter and a solid-state manometry catheter were placed in the stomach concomitantly. Motility was recorded for 2.5 h: 2 h in a fasting state, followed by a 400-kcal liquid meal, and monitoring of the fed state for the remaining half hour. The performance of both systems was compared by automated recognition and manual identification of the contractile activity. Data are presented as mean (standard deviation).

KEY RESULTS

The analysis set comprised 13 healthy subjects (6 women, age: 27.5 (8.1) years, BMI: 22.2 (2.46) kg/m2). Automatically-recognized contractility was strongly correlated between the two techniques (endpoint: contraction duration; Spearman ρ = 0.96, p < 0.001). A correlation was also observed between the number of individual contractions identified by expert gastroenterologists on both technologies independently (ρ = 0.71, p = .007) and between the contractions identified by the experts and by the GMS software (ρ = 0.87, p = 0.001). No serious or unanticipated adverse events occurred.

CONCLUSIONS & INFERENCES

The observed strong correlations with the gold standard, manometry, validate the performance of the VIPUN GMS as a gastric monitoring system.

Regional differences in stomach stretch during organ filling and their implications on the mechanical stress response

As part of the digestive system, the stomach plays a crucial role in the health and well-being of an organism. It produces acids and performs contractions that initiate the digestive process and begin the break-up of ingested food. Therefore, its mechanical properties are of interest. This study includes a detailed investigation of strains in the porcine stomach wall during passive organ filling. In addition, the observed strains were applied to tissue samples subjected to biaxial tensile tests. The results show inhomogeneous strains during filling, which tend to be higher in the circumferential direction (antrum: 13.2%, corpus: 22.0%, fundus: 67.8%), compared to the longitudinal direction (antrum: 4.8%, corpus: 24.7%, fundus: 50.0%) at a maximum filling of 3500 ml. Consequently, the fundus region experienced the greatest strain. In the biaxial tensile experiments, the corpus region appeared to be the stiffest, reaching nominal stress values above 400 kPa in the circumferential direction, whereas the other regions only reached stress levels of below 50 kPa in both directions for the investigated stretch range. Our findings gain new insight into stomach mechanics and provide valuable data for the development and validation of computational stomach models.

Diagnostic Methods for Evaluation of Gastric Motility-A Mini Review

Gastric motility abnormalities are common in patients with disorders of gut-brain interaction, such as functional dyspepsia and gastroparesis. Accurate assessment of the gastric motility in these common disorders can help understand the underlying pathophysiology and guide effective treatment. A variety of clinically applicable diagnostic methods have been developed to objectively evaluate the presence of gastric dysmotility, including tests of gastric accommodation, antroduodenal motility, gastric emptying, and gastric myoelectrical activity. The aim of this mini review is to summarize the advances in clinically available diagnostic methods for evaluation of gastric motility and describe the advantages and disadvantages of each test.

A Preclinical Feasibility Study of Endoscopic Barostat: A Possible Diagnostic Tool for Visceral Hypersensitivity in Functional Dyspepsia

INTRODUCTION

Diagnosing functional dyspepsia requires excluding organic disease and gastrointestinal function evaluation; however, there are no modalities to evaluate these simultaneously. This preclinical study examined the possibility of an endoscopic barostat.

METHODS

Ultrathin endoscopy and our newly developed pressure-regulated endoscopic insufflator, which insufflates the gastrointestinal tract until the preset pressure is achieved, were used. The actual intragastric pressure was measured using an optical fiber manometer placed in the stomach. Experiment-1: in an ex vivo experiment, we insufflated the isolated stomach and verified whether the intragastric pressure reached the preset pressure. Experiment-2: we inserted the endoscope orally in a porcine stomach, insufflated the stomach, and verified whether the intragastric pressure reached the preset pressure. Finally, we insufflated the stomach at a random pressure to verify the functional tests for proof-of-concept.

RESULTS

Experiment-1: the intragastric pressure reached the preset pressure. After reaching the plateau, the pressure remained stable at the preset pressure (Huber M value: 1.015, regression line: 0.988, 95% confidence interval [CI]: 0.994-0.994). Experiment-2: the intragastric pressure reached the preset pressure. After reaching the plateau, the pressure remained stable at the preset pressure (Huber M value: 1.018, regression line: 0.971, 95% CI: 0.985-0.986). At randomly preset pressures, the transendoscopic theoretical intragastric pressure detected by using the insufflator was correlated with the actual pressure measured by using the pressure manometer.

CONCLUSIONS

This proof-of-concept study shows that a pressure-regulated endoscopic insufflator provides stable intragastric pressure at the preset level, with the potential of an endoscopic barostat to assess the visceral hypersensitivity related to functional dyspepsia.

New endoscopic method for gastric hypersensitivity testing: Pilot study

Background and Aim

Although one of the causes of dyspeptic symptoms in functional dyspepsia patients is gastric hypersensitivity, there is currently no routine endoscopic gastric hypersensitivity test. We developed a new endoscopic method for gastric hypersensitivity testing. The aim of the present study was to investigate whether this method is useful for evaluating gastric hypersensitivity in drug‐resistant functional dyspepsia patients who were strongly suspected of having gastric hypersensitivity.

Methods

Twenty‐seven drug‐resistant functional dyspepsia patients and 27 nonfunctional dyspepsia patients were recruited. Gastric pressure was assessed using an external pressure transducer, and the CO₂ insufflation volume was measured using an endoscopic CO₂‐supplied device and flow meter. The following variables were examined: gastric pressure at baseline and gastric pressure, the CO₂ insufflation volume, and compliance of the stomach when patients initially felt abdominal tension following CO₂ insufflation.

Results

No significant differences were observed in baseline gastric pressure or compliance of the stomach between the groups. Drug‐resistant functional dyspepsia patients had a significantly smaller CO₂ insufflation volume and lower gastric pressure when symptoms developed than nonfunctional dyspepsia patients. Based on a cutoff value of 1.25 L by receiver operating characteristic curves, sensitivity and specificity for gastric pressure were 85.0 and 96.3%, respectively. Similarly, based on a cutoff value of 12.7 mmHg, sensitivity and specificity for the CO₂ insufflation volume were 81.5 and 81.5%, respectively.

Conclusion

This endoscopic gastric hypersensitivity testing is a useful tool for evaluating the presence of gastric hypersensitivity.

Ultrasound imaging for assessing functions of the GI tract

OBJECTIVE

In the following review we outline how ultrasound can be used to measure physiological processes in the gastrointestinal tract.

APPROACH

We have investigated the potential of ultrasound in assessing gastrointestinal physiology including original research regarding both basic methodology and clinical applications.

MAIN RESULTS

Our main findings show the use of ultrasound to study esophageal motility, measure volume and contractility of the stomach, assess motility, wall thickness, and perfusion of the small bowel, and evaluate wall vascularization and diameters of the large bowel.

SIGNIFICANCE

Ultrasound is a widely accessible technology that can be used for both scientific and clinical purposes. Being radiation-free and user friendly, the examination can be frequently repeated enabling longitudinal studies. Furthermore, it does not influence normal GI physiology, thus being useful to estimate motility and subtle changes in physiology. Accordingly, ultrasound scanning and physiological measurements may make a big difference for the scientist and the doctor; and for the patients who receive an efficient work-up.

[Ultrasound assessment of gastric insufflation in obese patients receiving transnasal humidified rapid-insufflation ventilatory exchange during general anesthesia induction]

OBJECTIVE

To assess the effect of transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) on gastric insufflation during general anesthesia induction in obese patients.

METHODS

Ninety obese patients (BMI 30-39.9 kg/m²) undergoing laparoscopic cholecystectomy under general anesthesia were randomized into 3 groups (n=30) to receive facemask pre- oxygenation followed by face mask ventilation (FMV) after administration of anesthetics (Group M), oxygenation with THRIVE (Group T), or pre-oxygenation with facemask combined with THRIVE followed continuous oxygenation with both FMV and THRIVE after administration of anesthetics (Group M+T). The patients in the latter two groups received continuous oxygen via THRIVE during tracheal intubation. All the patients received real-time ultrasound monitoring of the gastric antrum, and positive gastric insufflation (GI⁺) was defined by the presence of comet-tail artifacts. The cross-sectional area of the gastic antrum (CSA-GA) was measured by ultrasound before and after pre-oxygenation and after intubation. The patients' SpO₂, PaO₂, and PaCO₂ at admission (T₁), 5 min after pre-oxygenation (T₂), 5 min after medication (T₃), and immediately after intubation (T₄) were recorded, and the incidence of postoperative adverse events was assessed.

RESULTS

The incidence of gastric insufflation was significantly higher in Group M and Group M+T than in Group T (P < 0.05). The CSA-GA was significantly greater at T₄ than at T₁ in Group M and Group M+T and in their GI⁺s ubgroups. The GI⁺ subgroups in Group M and Group M+ T had significantly larger CSA-GA at T₄ than the GI^- subgroups (P < 0.05). CSA-GA did not vary significantly during anesthesia induction in Group T (P>0.05). The incidence of grade Ⅰ gastric distension was lower but grade Ⅱ gastric distention was higher in Group M and Group M+T than in Group T (P < 0.05). Group M showed significantly greater variations of PaO₂ at T₃ and T₄ than Group T and Group M+T (P < 0.05).

CONCLUSIONS

Ultrasound monitoring of the comet tail sign and the changes of CSA-GA in the gastric antrum is feasible and reliable for detecting gastrointestinal airflow, and in obese patients, the application of THRIVE for induction of anesthesia can ensure the oxygenation level without further increasing gastric insufflation.

Volume and position change of the stomach during gastric accommodation and emptying: A detailed three-dimensional morphological analysis based on MRI

BACKGROUND

The proximal and distal regions of the stomach are thought to have different roles during gastric accommodation and emptying; however, regional changes in gastric structure and function during and after a meal have not been described in detail. This study applied non-invasive imaging to study changes in regional gastric volume and morphology during accommodation and emptying of a liquid nutrient meal.

METHOD

MRI studies were performed on 16 healthy volunteers. Three-dimensional (3D) gastric morphology was reconstructed by validated image processing technology. The 3D models were segmented into seven regions. The relative contribution of each region to gastric accommodation and emptying was assessed. Changes in morphology were documented by tracking movements of four distinct gastric landmarks.

KEY RESULTS

The initial 100 mL liquid nutrient increases distal stomach volume more than that of other gastric regions (∆V7 = 28 ± 6% ∆TGV; P ≤ .05). Subsequent volume is accommodated mainly in the proximal stomach (∆V1 = 42 ± 10% ∆TGV; P ≤ .05). Early-phase emptying occurs from distal stomach with proximal stomach volume remaining stable. Subsequently, distal stomach volume remains stable while proximal stomach volume decreases progressively. During gastric filling, the stomach elongates and expands anteriorly and inferiorly (15.2 ± 7.4 mm and 32.3 ± 8.4 mm, respectively, for the incisural midpoint) with torsion indicated by ~70° difference in the movements of proximal and distal gastric landmarks.

CONCLUSIONS AND INFERENCES

Non-invasive MRI describes volume change and distribution of a liquid meal within proximal and distal stomach during gastric accommodation and emptying. Additionally, novel observations of changes to 3D gastric morphology within the abdomen are documented.

Ultrasound to guide the individual medical decision by evaluating the gastric contents and risk of aspiration: A literature review

Pulmonary aspiration of gastric contents is one of the most terrible complications following general anesthesia. It is important for patients to prevent this complication by obeying the preoperative fasting protocol strictly. At present, it has been reported by many studies that bedside ultrasound, as a non-invasive and convenient method, could be used to evaluate gastric contents qualitatively and quantitatively. With the advantages of reliability, accuracy and repeatability, it can greatly reduce the risk of aspiration and ensure patients' life security. But most of the data were acquired from the healthy volunteers. For the gastrointestinal disorder, the pregnant women, obesity, children, the elderly and diabetes patients, the accuracy and reliability of ultrasound to predict the risk of aspiration remains to be identified by more further studies. For these patients with increasing risk of aspiration, I-AIM (Indication, Acquisition, Interpretation, Medical decision-making) framework plays an important role in ensuring the safety of patients. It is crucial to make appropriate clinical decisions by evaluating the gastric contents with ultrasound.

GI Motility Testing: Stomach, Small Bowel, and Colon

Symptoms of abdominal pain, nausea, vomiting, bloating, abdominal distention, diarrhea, and constipation are common and may relate to abnormalities in gastrointestinal motility. There are a number of different options to study gastrointestinal motility. This article reviews novel and standard motility tests available in the stomach, small bowel, and colon. The indications for testing, technical details, advantages, and disadvantages of each test will be summarized.

Towards a Fuller Assessment of Gastric Motility in Patients With Upper GI Dyspepsia: Time to Accommodate!

There is increasing recognition of the importance of assessing patients with unexplained upper gastrointestinal symptoms for impaired gastric accommodation. New therapeutic approaches to treat impaired accommodation are being developed. This increasing interest in diagnosing and treating impaired gastric accommodation emphasizes the need to have a clinically available method to measure the gastric accommodation response. In this editorial, gastric accommodation is discussed along with the currently available methods for its assessment. We summarize our thoughts on what are the next steps needed to make a readily accessible method for assessing gastric accommodation more widely available.

A comparison of various intragastric balloons for the assessment of gastric motility

BACKGROUND

There is a clear need for a novel method to readily assess gastric motility in daily clinical practice.

METHODS

In a crossover design, 10 noncompliant balloons of different shape and volume (25-350 mL), attached to a classic feeding tube, were introduced in the stomach of eight healthy volunteers. In the same experiment, a High-Resolution Manometry (HRM) catheter was positioned throughout the stomach. Gastric motility was recorded during fasting (2 hours) and liquid nutrient administration (30 minutes). Motility was quantified using a peak detection algorithm. Symptoms were recorded throughout the experiment using visual analog scales (100 mm). Results are presented as mean ± SD.

KEY RESULTS

The % time during which motility-induced pressure increments could be detected with HRM but not by the balloon varied from 42 ± 24% in the smallest (25 mL) balloon to 1 ± 1% in the 330 mL balloon. On the other hand, bloating, discomfort and nausea scores were 0 ± 0, 0 ± 0 and 2 ± 5 mm, respectively, for the smallest balloon (25 mL) while these scores were 28 ± 38, 13 ± 30, and 38 ± 30 mm, respectively, for the largest balloon (350 mL). A phase III contraction pattern was consistently evoked in balloons with a volume >200 mL.

CONCLUSION

Gastric motility could be assessed more accurately with larger volume balloons, while epigastric symptoms were evoked with increasing balloon volume. The optimal balloon to measure gastric motility has a 5 cm diameter and is 11 cm long (210 mL). A nasogastric balloon catheter can now be developed that enables relatively easy monitoring of gastric motility in patients with epigastric symptoms.

Effects of Glutamine on Gastric Emptying of Low- and High-Nutrient Drinks in Healthy Young Subjects-Impact on Glycaemia

Glutamine is a potent stimulus for the release of glucagon-like peptide-1, which increases postprandial insulin and slows gastric emptying (GE). We determined the effects of glutamine on GE of, and glycaemic responses to, low- and high-nutrient drinks in eight healthy males (mean age 21.6 ± 0.7 years and BMI 22.9 ± 0.7 kg/m²). Participants were studied on four occasions on which they consumed either a low-nutrient (beef soup; 18 kcal) or high-nutrient (75 g dextrose; 255 kcal) drink, each with or without 30 g of glutamine (120 kcal), in a randomised, crossover design. GE (2D ultrasound), blood glucose and plasma insulin concentrations were measured concurrently. Glutamine slowed GE (half emptying time (T50)) of both low- (45 ± 3 min vs. 26 ± 2 min, p < 0.001), and high-nutrient, (100 ± 5 min vs. 77 ± 5 min, p = 0.03) drinks, however, there was no effect on GE of the high nutrient drinks when expressed as kcal/min (3.39 ± 0.21 kcal/min vs. 3.81 ± 0.20 kcal/min, p = 0.25). There was no change in blood glucose after the low-nutrient drinks with or without glutamine, despite a slight increase in plasma insulin with glutamine (p = 0.007). The rise in blood glucose following the high-nutrient drink (p = 0.0001) was attenuated during the first 60 min by glutamine (p = 0.007). We conclude that in healthy subjects, glutamine slows GE of both low- and high-nutrient drinks comparably and attenuates the rise in blood glucose after the high-nutrient glucose drink.

Contrast-Enhanced Magnetic Resonance Imaging of Gastric Emptying and Motility in Rats

The assessment of gastric emptying and motility in humans and animals typically requires radioactive imaging or invasive measurements. Here, we developed a robust strategy to image and characterize gastric emptying and motility in rats based on contrast-enhanced magnetic resonance imaging (MRI) and computer-assisted image processing. The animals were trained to naturally consume a gadolinium-labeled dietgel while bypassing any need for oral gavage. Following this test meal, the animals were scanned under low-dose anesthesia for high-resolution T1-weighted MRI in 7 Tesla, visualizing the time-varying distribution of the meal with greatly enhanced contrast against non-gastrointestinal (GI) tissues. Such contrast-enhanced images not only depicted the gastric anatomy, but also captured and quantified stomach emptying, intestinal filling, antral contraction, and intestinal absorption with fully automated image processing. Over four postingestion hours, the stomach emptied by 27%, largely attributed to the emptying of the forestomach rather than the corpus and the antrum, and most notable during the first 30 min. Stomach emptying was accompanied by intestinal filling for the first 2 h, whereas afterward intestinal absorption was observable as cumulative contrast enhancement in the renal medulla. The antral contraction was captured as a peristaltic wave propagating from the proximal to distal antrum. The frequency, velocity, and amplitude of the antral contraction were on average 6.34 ± 0.07 contractions per minute, 0.67 ± 0.01 mm/s, and 30.58 ± 1.03%, respectively. These results demonstrate an optimized MRI-based strategy to assess gastric emptying and motility in healthy rats, paving the way for using this technique to understand GI diseases, or test new therapeutics in rat models.The assessment of gastric emptying and motility in humans and animals typically requires radioactive imaging or invasive measurements. Here, we developed a robust strategy to image and characterize gastric emptying and motility in rats based on contrast-enhanced magnetic resonance imaging (MRI) and computer-assisted image processing. The animals were trained to naturally consume a gadolinium-labeled dietgel while bypassing any need for oral gavage. Following this test meal, the animals were scanned under low-dose anesthesia for high-resolution T1-weighted MRI in 7 Tesla, visualizing the time-varying distribution of the meal with greatly enhanced contrast against non-gastrointestinal (GI) tissues. Such contrast-enhanced images not only depicted the gastric anatomy, but also captured and quantified stomach emptying, intestinal filling, antral contraction, and intestinal absorption with fully automated image processing. Over four postingestion hours, the stomach emptied by 27%, largely attributed to the emptying of the forestomach rather than the corpus and the antrum, and most notable during the first 30 min. Stomach emptying was accompanied by intestinal filling for the first 2 h, whereas afterward intestinal absorption was observable as cumulative contrast enhancement in the renal medulla. The antral contraction was captured as a peristaltic wave propagating from the proximal to distal antrum. The frequency, velocity, and amplitude of the antral contraction were on average 6.34 ± 0.07 contractions per minute, 0.67 ± 0.01 mm/s, and 30.58 ± 1.03%, respectively. These results demonstrate an optimized MRI-based strategy to assess gastric emptying and motility in healthy rats, paving the way for using this technique to understand GI diseases, or test new therapeutics in rat models.

The predictive value of hunger score on gastric evacuation after oral intake of carbohydrate solution

BACKGROUND

Surgical patients are asked to fast for a sufficient duration to ensure that the amount of residual liquid in the stomach is within the safe range, thereby reducing the risk of gastric reflux perioperatively. The authors hypothesized that subjective hunger numerical rating scale (NRS) score could also help assess the process of gastric emptying and determine the amount of fluid remaining in the stomach.

METHODS

The current study consisted of healthy volunteers recruited by advertisement and mutual introduction. Participants were asked to rate their subjective hunger feeling every 30 min after oral administration of 8 mL/kg carbohydrate nutrient solution that contained 10% maltodextrin and 2.5% sucrose. Consecutively, the gastric residual fluid was measured by magnetic resonance imagining (MRI). The Spearman's correlation coefficient, the ROC curves and the stepwise regression were used to analyze the predictive value of NRS for the gastric emptying process.

RESULTS

The cohort consisted of 29 healthy volunteers enrolled in this study. The area under ROC curves estimated by the NRS score for the gastric residual volume of 2 mL/kg, 1 mL/kg, and 0.5 mL/kg were AUC2.0 = 0.78, AUC1.0 = 0.76, and AUC0.5 = 0.72, respectively. The correlation coefficient between the NRS score and the residual liquid in the stomach was -0.57 (P < 0.01). The correlation coefficient between the increase of the NRS score and the decrease of gastric liquid residual volume was 0.46 (P < 0.01). The standardized estimate of NRS score for the residual volume was -0.18 (P < 0.01) and the standardized estimate of fasting time was -0.73 (P < 0.01).

CONCLUSIONS

The subjective hunger NRS score can not accurately predict the gastric residual volume, but it can provide a reference for clinicians to judge the gastric emptying process and it should be used as a second check after oral intake of clear fluids before surgery according to the new fasting protocol.

Assessment of Gastric Accommodation in Patients with Functional Dyspepsia by 99mTc-Pertechtenate Single Photon Emission Computed Tomography Imaging: Practical but not Widely Accepted

Objective:

Impaired gastric accommodation is one of the main symptoms in patients with functional dyspepsia. The aim of the present study was to assess gastric accommodation in patients with functional dyspepsia using single photon emission computed tomography (SPECT) imaging.

Methods:

Twenty-four patients with functional dyspepsia and 50 healthy volunteers as control group were enrolled in this study. All participants were given 5 mCi 99mTc-pertechtenate intravenously, served with a low fat meal, and underwent SPECT scanning 20 minutes after the meal.

Results:

Based on the scintigraphic data, gastric volumes were found to be significantly increased after food ingestion in both patient and control groups. We also found that while there was no significant difference between patient and control groups in terms of fasting gastric volumes, postprandial gastric volume was significantly lower in patients as compared to healthy individuals (p<0.05).

Conclusion:

Measuring gastric volume by using SPECT can be a valuable method in the detection of functional dyspepsia and in differentiation of this entity from other organic disorders.

The ultrasound meal accommodation test in 509 patients with functional gastrointestinal disorders

AIM

The Ultrasound Meal Accommodation Test (UMAT) is a clinical test used to assess gastric accommodation, gastric emptying, and visceral sensitivity. It has been used as a clinical tool at Haukeland University Hospital, Bergen for more than 20 years.

MATERIAL AND METHODS

Five-hundred and nine patients were retrospectively evaluated, 71% females, and 51% were referred from other hospitals or specialists. The aim was to explore the usefulness of UMAT in patients with suspected functional GI disorders (FGID).

RESULTS

One hundred and sixty patients were diagnosed with functional dyspepsia (FD), and 154 patients were diagnosed with irritable bowel syndrome (IBS). The overlap between IBS and FD was 41%. In 36% of FD patients, ultrasound assessment showed impaired gastric accommodation. Of 262 patients filling out all required fields for the FD diagnosis (ROMA II and III), 198 (74%) met the criteria for FD, but only 91 (34%) were later diagnosed with FD by an experienced clinician.

CONCLUSIONS

By combining ultrasonography, the symptom response to a standardized meal, and psychological assessment, the UMAT is useful in diagnosis and management of patients with FGID.

Evaluation of Gastric Volumes: Comparison of 3-D Ultrasound and Magnetic Resonance Imaging

To investigate gastric accommodation, accurate measurements of gastric volumes are necessary. An excellent technique to measure gastric volumes is dynamic magnetic resonance imaging (MRI). Unfortunately, dynamic MRI is expensive and not always available. A new 3-D ultrasound (US) method using a matrix transducer was developed to measure gastric volumes. In this prospective study, 14 healthy volunteers underwent a dynamic MRI and a 3-D US. Gastric volumes were calculated with intra-gastric liquid content and total gastric volume. Mean postprandial liquid gastric content was 397 ± 96.5 mL. Mean volume difference was 1.0 mL with limits of agreement of -8.9 to 10.9 mL. When gastric air was taken into account, mean total gastric volume was 540 ± 115.4 mL SD. Mean volume difference was 2.3 mL with limits of agreement of -21.1 to 26.4 mL. The matrix 3-D US showed excellent agreement with dynamic MRI. Therefore matrix 3-D US is a reliable alternative to measure gastric volumes.

Validation of a Novel 3-Dimensional Sonographic Method for Assessing Gastric Accommodation in Healthy Adults

OBJECTIVES

A novel automated 3-dimensional (3D) sonographic method has been developed for measuring gastric volumes. This study aimed to validate and assess the reliability of this novel 3D sonographic method compared to the reference standard in 3D gastric sonography: freehand magneto-based 3D sonography.

METHODS

A prospective study with 8 balloons (in vitro) and 16 stomachs of healthy volunteers (in vivo) was performed. After a 500-mL liquid meal, 1 preprandial and 3 postprandial volume scans of the stomachs were performed by the novel 3D sonographic method and the current reference-standard 3D sonographic method.

RESULTS

The in vitro study showed a mean volume difference between the novel method and the true balloon volume of -1.3 mL; limits of agreement (LoA) were small (-39.3 to12.3 mL), with an intraclass correlation coefficient (ICC) of 0.998. The in vivo study showed a mean gastric volume of 321 mL between the novel method and the freehand magneto-based method, with a mean volume difference of -4.4 mL; LoA were -40.1 to 31.2 mL, and the ICC was 0.991. The intraobserver and interobserver variability rates were low, at 0.8 mL (LoA, -24.0 to 25.6 mL), with an ICC of 0.995, and 0.5 mL (LoA, of -26.8 to 27.8 mL), with an ICC of 0.999, respectively.

CONCLUSIONS

The novel 3D sonographic method with automated acquisition showed good agreement with the current reference-standard gastric 3D sonographic method, with low intraobserver and interobserver variability. This novel 3D sonographic method is a valid and reliable technique for determining gastric accommodation.

A Multiphase Flow in the Antroduodenal Portion of the Gastrointestinal Tract: A Mathematical Model

A group of authors has developed a multilevel mathematical model that focuses on functional disorders in a human body associated with various chemical, physical, social, and other factors. At this point, the researchers have come up with structure, basic definitions and concepts of a mathematical model at the "macrolevel" that allow describing processes in a human body as a whole. Currently we are working at the "mesolevel" of organs and systems. Due to complexity of the tasks, this paper deals with only one meso-fragment of a digestive system model. It describes some aspects related to modeling multiphase flow in the antroduodenal portion of the gastrointestinal tract. Biochemical reactions, dissolution of food particles, and motor, secretory, and absorbing functions of the tract are taken into consideration. The paper outlines some results concerning influence of secretory function disorders on food dissolution rate and tract contents acidity. The effect which food density has on inflow of food masses from a stomach to a bowel is analyzed. We assume that the future development of the model will include digestive enzymes and related reactions of lipolysis, proteolysis, and carbohydrates breakdown.

Measurement of Gastrointestinal and Colonic Motor Functions in Humans and Animals

Accurately measuring the complex motor behaviors of the gastrointestinal tract has tremendous value for the understanding, diagnosis and treatment of digestive diseases. This review synthesizes the literature regarding current tests that are used in both humans and animals. There remains further opportunity to enhance such tests, especially when such tests are able to provide value in both the preclinical and the clinical settings.

Acute exercise and gastric emptying: a meta-analysis and implications for appetite control

BACKGROUND

Gastric emptying (GE) could influence exercise-induced changes in appetite and energy intake. GE also could contribute to changes in gastric symptoms and the availability of nutrients during exercise, which will subsequently affect performance.

OBJECTIVE

The objective of this review was to determine the effects of acute exercise on GE using a systematic review and meta-analysis. The most common parameters to determine GE were selected, consisting of half-emptying time and volume emptied. Oral-caecal transit time (OCTT) was also examined.

DATA SOURCES

Research databases (PubMed, Scopus, Google Scholar, EBSCOhost, SPORTDiscus) were searched through November 2013 for original studies, abstracts, theses and dissertations that examined the influence of acute exercise on GE.

STUDY SELECTION

Studies were included if they evaluated GE or OCTT during and/or after exercise and involved a resting control trial.

STUDY APPRAISAL AND SYNTHESIS

Initially, 195 studies were identified. After evaluation of study characteristics and quality and validity, data from 20 studies (35 trials) involving 221 participants (157 men; 52 women; 12 unknown) were extracted for meta-analysis. Random-effects meta-analyses were utilised for the three main outcome variables, and effect sizes (ES) are reported as Hedge's g due to numerous small sample sizes.

RESULTS

Random-effects modelling revealed non-significant and small/null main effect sizes for volume emptied (ES = 0.195; 95% CI -0.25 to 0.64), half-time (ES = -0.109, 95% CI -0.66 to 0.44) and OCTT (ES = 0.089; 95% CI -0.64 to 0.82). All analyses exhibited significant heterogeneity and numerous variables moderated the results. There was a dose response of exercise intensity; at lower intensities GE was faster, and at high exercise intensities GE was slower. Walking was associated with faster GE and cycling with slower GE. Greater volume of meal/fluid ingested, higher osmolality of beverage and longer exercise duration were also associated with slower GE with exercise.

LIMITATIONS

The major limitation is that the majority of studies utilised a liquid bolus administered pre-exercise to determine GE; the relationship to post-exercise appetite and energy intake remains unknown. Study populations were also generally active or trained individuals. Furthermore, our review was limited to English language studies and studies that utilised resting control conditions.

CONCLUSIONS

These results suggest that exercise intensity, mode, duration and the nature of meal/fluid ingested all influence GE during and after acute exercise. The relationship of GE parameters with appetite regulation after exercise remains largely unexplored. Further integrative studies combining GE and alterations in gut hormones, as well as in populations such as overweight and obese individuals are needed.

Alternate current biosusceptometry for the assessment of gastric motility after proximal gastrectomy in rats: a feasibility study

BACKGROUND

This study proposes an experimental model to assess the consequences of gastric surgeries on gastric motility. We investigated the effects of proximal gastrectomy (PG) using a non-invasive technique (alternate current biosusceptometry [ACB]) on gastric contractility (GC), gastric emptying (GE), and orocecal transit (OCT) after the ingestion of liquids and solids in rats.

METHODS

Twenty-four male rats were subjected to gastric motility assessment before and after the PG procedure. The GE and OCT results are expressed as the mean time of gastric emptying (MGET) and cecum arrival (MCAT). The GC recordings are presented as the frequency and amplitude of contractions.

KEY RESULTS

Mean time of gastric emptying after solid meals were significantly different (p < 0.001) between control and PG (113 ± 5 to 99 ± 6 min). Mean time of cecum arrival ranged from 265 ± 9 to 223 ± 11 min (p < 0.001) and 164 ± 9 to 136 ± 17 min (p < 0.050) for solid and liquid meals, respectively. The assessment of GC showed that surgery decreased the phasic frequency (4.4 ± 0.4 to 3.0 ± 1.1 cpm, p < 0.050) and increased the amplitude of contractions (3.6 ± 2.7 to 7.2 ± 3.0 V/s, p < 0.050). No significant difference was found in tonic frequency.

CONCLUSIONS & INFERENCES

The ACB system was able to assess GE, OCT, and GC in gastrectomized rats. Overall, PG accelerated GE and gastrointestinal transit, likely due to the increase in both intragastric pressure and amplitude contraction. Our data presented an efficient model to investigate functional consequences from gastric surgeries that will allow further studies involving different procedures.

Gastrointestinal dysfunction in liver cirrhosis

Patients with liver cirrhosis exhibit several features of gut dysfunction which may contribute to the development of cirrhosis complications as well as have an impact on nutritional status and health-related quality of life. Gastrointestinal symptoms are common in cirrhosis and their pathophysiology probably involves factors related to liver disease severity, psychological distress, and gut dysfunction (e.g., increased gastric sensitivity to distension and delayed gut transit). They may lead to reduced food intake and, thus, may contribute to the nutritional status deterioration in cirrhotic patients. Although tense ascites appears to have a negative impact on meal-induced accommodation of the stomach, published data on gastric accommodation in cirrhotics without significant ascites are not unanimous. Gastric emptying and small bowel transit have generally been shown to be prolonged. This may be related to disturbances in postprandial glucose, insulin, and ghrelin levels, which, in turn, appear to be associated to insulin resistance, a common finding in cirrhosis. Furthermore, small bowel manometry disturbances and delayed gut transit may be associated with the development of small bowel bacterial overgrowth. Finally, several studies have reported intestinal barrier dysfunction in patients with cirrhosis (especially those with portal hypertension), which is related to bacterial translocation and permeation of intestinal bacterial products, e.g., endotoxin and bacterial DNA, thus potentially being involved in the pathogenesis of complications of liver cirrhosis.

Intragastric volume changes after intake of a high-caloric, high-fat standard breakfast in healthy human subjects investigated by MRI

The aim of this magnetic resonance imaging (MRI) study was to investigate gastric emptying after intake of a high-caloric and high-fat standard meal as recommended by FDA and EMA for food-effect bioavailability and fed bioequivalence studies. Twelve healthy human subjects (7 male, 5 female) received the standard meal after an overnight fast. MRI was performed before as well as 15, 25, 35, 45, 55, 65, 105, 195, 275, and 375 min after meal intake using strong T2-weighted sequences and chemical shift imaging. In addition, 30 min after the beginning of meal intake subjects ingested 240 mL of water representing the recommended coadministration of water during drug intake. Gastric content volume was assessed using T2-weighted images, and fat fraction was estimated using a calculation of fat fraction in chemical shift imaging. In addition, the existence of a mechanism allowing fast gastric emptying of water in the fed state was investigated. After a lag phase of 50-90 min, gastric content volume decreased constantly with a rate of 1.7 mL/min. The water ingested 30 min after the start of the meal intake directly reached the antrum and subsequently was emptied quickly from the human stomach. Complete gastric emptying within 6 h was observed in only one out of 12 subjects. The fat fraction of the intragastric chyme decreased from 9.5% directly after meal intake to 6.3% at the end of the experiments. Moreover, the fat fraction in fundus was significantly higher compared to the antrum. This study contributes fundamental data for the assessment of food effects of solid oral dosage forms.

Impact of eating restriction on gastrointestinal motility in adolescents with IBS

OBJECTIVE

Gastrointestinal disturbances as a result of changes in eating patterns have been described in eating disorders. Many patients who experience irritable bowel syndrome report changes in eating patterns as a way to cope with their symptoms. Little is known about the consequences of these practices. The aim of this study was to explore whether repeated eating restriction (defined as not eating ≥ 4 hours while hungry) is associated with motility disturbances.

METHODS

Of 17 patients with irritable bowel syndrome, subjects were divided into those who habitually restrict their eating (n = 8) and those without eating restriction (n = 9) (age range 15-21, mean 19.2; 64.7% girls). Whole-gut transit time was measured by radiopaque markers, gastric sensitivity was measured by water load test (drinking max of 800 mL of water in 5 minutes or until full), and gastric dysrhythmias by an electrogastrogram.

RESULTS

Restrictors drank less water (mean 464.4 mL) than nonrestrictors (mean 613 mL; P = 0.02). No difference was found in gastric dysrhythmias (62.5% vs 77.8%; P = 0.5). Whole-gut transit tended to be slower in the restrictors (mean 51.0 hours) than in nonrestrictors (mean 37.5 hours), but this was not significant.

CONCLUSIONS

Eating restriction appears to be associated with increased gastric sensation. More data are needed from larger studies to determine whether eating behaviors are associated with other motility disturbances.

Gastroparesis: from concepts to management

While the symptoms of gastroparesis are common, an accurate diagnosis is based on a combination of those symptoms with a documented delay in gastric emptying. Typical symptoms include nausea, vomiting, early satiety, postprandial fullness, bloating, and abdominal discomfort. Patients with gastroparesis face many diagnostic and therapeutic challenges. The most common origins of gastroparesis are idiopathic causes and diabetes mellitus. The increased use of certain medications in medicine today, including opiates and drugs with anticholinergic properties, can alter gastrointestinal functions and mimic symptoms of gastroparesis. Accordingly, alternative explanations for symptoms and altered gastrointestinal function need to be considered. Numerous clinical sequelae, including weight loss and severe protein-calorie malnutrition, may be seen in advanced stages of gastroparesis. This article provides an overview of gut sensorimotor function to help the reader better understand the clinical presentation of patients with dyspepsia and those who may have accompanying delayed gastric emptying that meets criteria for gastroparesis. Techniques available for diagnosing motor dysfunction and the principles of gastroparesis management are reviewed. Nutrition recommendations and a review of pharmacologic agents, nonpharmacologic techniques, and novel treatment modalities are provided.

Designing food structures for nutrition and health benefits

In addition to providing specific sensory properties (e.g., flavor or textures), there is a need to produce foods that also provide functionality within the gastrointestinal (GI) tract, over and above simple nutrition. As such, there is a need to understand the physical and chemical processes occurring in the mouth, stomach, small intestine, and large intestine, in addition to the food structure-physiology interactions. In vivo techniques and in vitro models have allowed us to study and simulate these processes, which aids us in the design of food microstructures that can provide functionality within the human body. Furthermore, it is important to be aware of the health or nutritional needs of different groups of consumers when designing food structures, to provide targeted functionality. Examples of three groups of consumers (elderly, obese, and athletes) are given to demonstrate their differing nutritional requirements and the formulation engineering approaches that can be utilized to improve the health of these individuals. Eating is a pleasurable process, but foods of the future will be required to provide much more in terms of functionality for health and nutrition.

Assessment of nonrespiratory stomach motion in healthy volunteers in fasting and postprandial states

PURPOSE

To characterize nonrespiratory stomach motion in the fasting state and postprandial.

METHODS AND MATERIALS

Ten healthy volunteers underwent 2-dimensional Fiesta cine magnetic resonance imaging studies in 30-second voluntary breath hold, in axial, coronal, and 2 oblique planes while fasting, and 5, 15, 30, 45, and 60 minutes postmeal. Each stomach contour was delineated and sampled with 200 points. Matching points were found for all contours in the same 30-second acquisition. Using deformable parametric analysis (Matlab, version 7.1), mean magnitude, and standard deviation of displacement of each point were determined for each patient. Maximal, minimal, and median population values in 6 cardinal, and in any direction, were calculated.

RESULTS

The median of mean displacements for the baseline position of each point was small and rarely exceeded 1.1 mm; greatest value was 1.6 mm superior-inferior. Median displacement (pooled across time) in the right-left, superior-inferior, and anterior-posterior directions was 0.3 (range, -0.7 to 1.3), 0.8 (-0.4 to 2.4), and 0.3 (-1.1 to 1.6) mm, respectively. Fasting and postprandial standard deviation did not differ.

CONCLUSIONS

Nonrespiratory stomach displacement is small and stomach position is stable after a small, standard meal. Radiation therapy may be delivered at any time within the first hour after eating without significant compromise of planned planning target volumes.

Effect of acute auditory stress on gastric motor responses to a meal in healthy volunteers

BACKGROUND AND AIM

Stress is believed to play a role in the pathogenesis of functional gastrointestinal disorders. The aim of the present study was to investigate the effect of acute auditory stress on gastric motor responses to a meal in healthy subjects.

METHODS

A total of eight healthy volunteers (seven men and one woman; median age, 33.4 years [30-35 years]) who had no recurrent gastrointestinal symptoms participated in the prospective, randomized, crossover study. Gastric half-emptying time and meal-induced proximal gastric accommodation were measured using gastric scintigraphy under the auditory stress and control conditions in a randomized crossover design.

RESULTS

The gastric half-emptying time under the stress condition was significantly longer than that under the control condition (130.8 ± 16.6 vs. 105.0 ± 13.1 min; P = 0.005 by paired t-test). Under the stress and control conditions, the proximal gastric volume significantly increased after a meal (P < 0.001 by repeated measures analysis of variance). The degree of the postprandial increase in proximal gastric volume did not significantly differ between both conditions (P = 0.598 by tests of between-subjects effects using repeated measures analysis of variance). The severity scores of postprandial epigastric discomfort and fullness were significantly higher under the stress condition than under the control condition (P = 0.001 and P = 0.039, respectively, by paired t-test).

CONCLUSIONS

Acute auditory stress delays gastric emptying and increases the severity of postprandial symptoms in the healthy subjects, suggesting the relevance of psychological stress to the pathophysiological mechanism of functional dyspepsia.

Effect of nutritional rehabilitation on gastric motility and somatization in adolescents with anorexia

OBJECTIVE

To examine gastric function, as well as the presence of somatic complaints, anxiety symptoms, and functional gastrointestinal disorders (FGIDs), in adolescents with anorexia nervosa (AN) before and after nutritional rehabilitation.

STUDY DESIGN

Sixteen females with AN and 22 healthy controls with similar demographic profiles were included. Gastric emptying (measured as residual gastric volume) and gastric accommodation (measured as postprandial antral diameter) were assessed with abdominal ultrasonography. Participants completed the Children's Somatization Inventory (CSI), the Screen for Child Anxiety-Related Emotional Disorders, and the Questionnaire on Pediatric Gastrointestinal Symptoms-Rome III version. All testing was repeated 3-4 months later.

RESULTS

Body mass index in the AN group improved over time (P = .012). Fasting gastric parameters were similar in the 2 groups. Maximum postprandial antral diameter was significantly greater in controls compared with the AN group (P = .008). Only adolescents with AN demonstrated a significant increase in maximum postprandial diameter at repeat testing (P = .009). There was no difference in residual gastric volume between the 2 groups. Initial CSI scores were higher in adolescents with AN (P < .0001), including higher scores for nausea and abdominal pain. CSI scores were significantly lower in adolescents with AN (P = .035). Initial scores on the Screen for Child Anxiety-Related Emotional Disorders were significantly higher in adolescents with AN (P = .0005), but did not change over time. Adolescents with AN met significantly more criteria for FGIDs (P = .003).

CONCLUSION

Adolescents with AN have impaired gastric accommodation that improves after nutritional rehabilitation, have significantly more somatic complaints, and meet more criteria for anxiety disorders and FGIDs. After nutritional rehabilitation, somatization improves and FGIDs become less common, but symptoms of anxiety persist.

Use of scintigraphy to evaluate gastric accommodation and emptying: comparison with barostat

BACKGROUND AND AIM

Scintigraphy is a useful noninvasive technique for assessment of gastric motility, especially emptying, but there is little knowledge of use of the technique to assess gastric accommodation. Therefore, to clarify the usefulness of scintigraphy as a technique for assessing gastric accommodation, we compared scintigraphy with barostat, the gold standard modality.

METHODS

Twenty healthy volunteers (14 men, six women; mean age, 28.5 ± 5.4 years) were enrolled in the study. The volunteers ingested a radiolabeled ((99m) Tc) test meal and scintigraphic images were recorded. Radioactivity in the upper third and whole stomach was calculated to evaluate accommodation. In the barostat procedure, gastric accommodation was evaluated by measuring the maximum volume of the distended balloon. Thereafter, correlation between scintigraphic and barostat accommodation was investigated. Intra-and inter-observer variation of the scintigraphic test results were also assessed. Finally, the diagnostic performance of scintigraphy was evaluated by using sumatriptan as a positive control.

RESULTS

Measurements of accommodation by scintigraphy and barostat correlated (r = 0.524, P < 0.05). Sumatriptan significantly increased scintigraphically measured gastric accommodation (with sumatriptan, 51.5 ± 16.4%; without sumatriptan, 38.4 ± 13.8%) (P < 0.01), and had significantly (P < 0.05) delayed 50% half emptying time at 60, 90, 120, and 150 min after the start of the experiment. The data from repeated scintigraphic tests were highly reproducible (r = 0.804) with significant differences not observed among the investigators (inter-observer variation = 0.932, intra-observer variation = 0.898).

CONCLUSION

Gastric scintigraphy is a useful technique for assessing gastric accommodation and emptying.

Relationship between vomiting reflex during esophagogastroduodenoscopy and dyspepsia symptoms

AIM

Although frequent vomiting reflexes during esophagogastroduodenoscopy (EGD) causes suffering in patients, very few studies have investigated the characteristics of subjects who frequently develop vomiting reflexes. This study examined the incidence of the vomiting reflex and related factors, especially upper gastrointestinal symptoms, among individuals undergoing transoral EGD.

METHODS

Subjects included 488 consecutive adults (mean age, 56.1 ± 8.9 years) who underwent transoral EGD for gastric cancer screening between February 2010 and March 2011. All procedures were performed by an endoscopist with 15 years of experience. Based on a questionnaire survey using the frequency scale for the symptoms of gastroesophageal reflux disease (FSSG), symptoms (dyspepsia and acid reflux symptoms) and the number of vomiting reflexes during EGD were recorded.

RESULTS

Of the 488 subjects, 271 (56%) developed vomiting reflexes (mean, 4.2 times). This reflex-positive group was younger (54.3 ± 9.5 years) than the reflex-negative group (58.3 ± 7.7 years, P < 0.001). The number of subjects in the reflex-positive group with a high FSSG dyspepsia score (2.27 ± 2.57 vs 1.23 ± 1.84; P < 0.001), acid reflux symptom score (1.96 ± 2.22 vs 1.34 ± 2.14; P < 0.01) or an esophageal hiatal hernia (14.8% vs 4.6%; P < 0.001) was significantly higher than in the reflex-negative group. Multivariate analysis also showed a significant correlation between these four factors and the occurrence of vomiting reflexes. Using an FSSG dyspepsia score of 1 as the cut-off offered 68% sensitivity and 57% specificity for predicting the occurrence of vomiting reflexes.

CONCLUSION

Based on FSSG questionnaire responses on upper gastrointestinal symptoms, dyspepsia symptoms, in particular, are related to presence of vomiting reflexes during EGD.

Does gastric volume in trauma patients identify a population at risk for developing pneumonia and poor outcomes?

BACKGROUND

Trauma patients may have full stomachs or impaired airway reflexes that place them at risk for aspiration and pneumonia. Our hypothesis was that trauma patients with larger gastric volumes as measured by abdominal computed tomography (CT) at admission have higher rates of pneumonia and worse outcomes.

METHODS

We matched an initial cohort of 81 trauma patients with an admission CT of the abdomen and a diagnosis of pneumonia by Injury Severity Score and Abbreviated Injury Score of the head and chest with a control group of 81 trauma patients without pneumonia. We estimated gastric volumes on CT and compared variables using chi-square, t-tests, receiver operating curve analysis, and regression analysis.

RESULTS

Patients with pneumonia had larger gastric volumes than those without pneumonia (879 cm(3)versus 704 cm(3); P = 0.04). Receiver operating curve analysis gave a gastric volume threshold value of 700 cm(3) as a predictor of pneumonia. Patients with a gastric volume ≥ 700 cm(3) had more pneumonia (61% versus 41%; P = 0.01), stayed longer in the hospital (27.6 versus 19.7 d; P < 0.05) and the intensive care unit (18.4 versus 12.5 d; P = 0.01), required more days on the ventilator (18.1 versus 12.0 d; P = 0.02), and had a trend toward increased mortality (17% versus 11%; P = 0.2). On multivariate analysis, nasogastric or orogastric tube (odds ratio 3.0; P = 0.004) and gastric volume >700 cm(3) (odds ratio 2.7; P = 0.004) were independent predictors of pneumonia.

CONCLUSIONS

Trauma patients who developed pneumonia had larger initial gastric volumes. A straightforward estimate of gastric volume on admission abdominal CT may predict patients at risk for developing pneumonia and poor outcomes. Clinicians should be especially vigilant in taking precautions against pneumonia and have a lower threshold for suspecting pneumonia in patients with abdominal CT gastric volumes ≥ 700 cm(3).

A placebo-controlled trial of an oral capsaicin load in patients with functional dyspepsia

BACKGROUND

The pathophysiology of functional dyspepsia is poorly understood. Visceral hypersensitivity may play a key role. We studied a previously validated test to assess chemical hypersensitivity in functional dyspepsia by applying an oral capsaicin load.

METHODS

A total of 116 outpatients with upper gastrointestinal (GI) symptoms participated in this double-blind, placebo-controlled trial of which 73 patients received a final diagnosis of functional dyspepsia. Patients swallowed a capsule containing 0.75 mg capsaicin or placebo. A graded questionnaire evaluated the severity of nine upper GI symptoms before and after capsule ingestion and an aggregate symptom score was calculated. A final score of >9 was considered as a positive test.

KEY RESULTS

In functional dyspepsia, median perception scores were 10.8 (interquartile range: 4.5-18.8) after ingestion of capsaicin and 0.5 (0.0-2.5) after placebo (P < 0.001). Thirty-seven functional dyspepsia patients (54%) had a positive test after capsaicin ingestion, whereas only four (11%) patients with upper GI symptoms but without functional dyspepsia were capsaicin positive [median perception score: 1.5 (0.0-5.0)]. After placebo, symptom scores were low and not significantly different among patient groups (P > 0.05). Clinical characteristics, age, and gender distribution was similar in capsaicin positive and capsaicin negative functional dyspepsia patients (P > 0.05). The value of patient blinding was good.

CONCLUSIONS & INFERENCES

Half of functional dyspepsia patients had chemical hypersensitivity, determined with an oral capsaicin load. Placebo response was negligible. The results of the capsaicin test were not associated with specific dyspepsia symptoms or Rome subgroups.

Inhibitory effects of desvenlafaxine on gastric slow waves, antral contractions, and gastric accommodation mediated via the sympathetic mechanism in dogs

Desvenlafaxine succinate (DVS; Pristiq) is a new antidepressant, serotonin-norepinephrine reuptake inhibitor. Antidepressants have been widely used for the treatment of functional gastrointestinal disorders. Possible roles of DVS on gastrointestinal motility have not been studied. The aim of this study was to investigate the effects of DVS on gastric slow waves (GSW), antral contractions, and gastric accommodation in dogs. Fifteen healthy dogs implanted with gastric serosal electrodes and a gastric cannula were studied in four separate sessions: control, DVS (50 mg), propranolol (1 mg·kg(-1)·h(-1)), and propranolol + DVS. GSW were measured via the gastric serosal electrodes. Antral contractions were assessed via an intraluminal manometric catheter inserted via the gastric cannula. The sympathovagal activity was assessed from the spectral analysis of the heart rate variability signal. Gastric tone was measured by barostat via an intragastric balloon inserted into the fundus via the gastric cannula. In the postprandial period, in comparison with the control, DVS reduced the percentage of normal GSW (P=0.001) and increased the percentage of tachygastria (P=0.005) and bradygastria (P=0.002). Simultaneously, DVS increased the sympathetic activity (P=0.006) and the sympathovagal ratio (low frequency/high frequency; P=0.044). These effects were blocked by propranolol. DVS attenuated postprandial antral contractions and gastric accommodation. The postprandial antral contractile index (area under the curve) was decreased by 26% with DVS (P=0.013), and gastric accommodation was decreased by about 50% with DVS (P < 0.001). The inhibitory effect of DVS on gastric accommodation was blocked by propranolol. DVS inhibits gastric contractions, slow waves, and accommodation in the fed state. These inhibitory effects are associated with an increased sympathetic modulation in the gastrointestinal system. Cautions should be made when DVS is used for treating patients with depression and gastric motility disorders.

Characterization of a reproducible gastric pain model using oral capsaicin titration in healthy volunteers

BACKGROUND

  Sensory sensitization is one of the main pathophysiological hypotheses in functional gastrointestinal disorders (FGIDs). As sensitization may affect various sensory modalities, we aimed to develop a reproducible gastric pain model utilizing polymodal pathways for use in functional and other pain disorders.

METHODS

In this double-blind, cross-over study 42 healthy subjects swallowed one capsule containing either capsaicin 0.5mg or nocebo every 15min until moderate pain (intensity >30 on 100mm visual analogue scale) was attained for at least 5min. Pain was rated every minute. Capsaicin titration was repeated thrice for reliability calculation.

KEY RESULTS

Moderate pain in the upper abdomen was successfully achieved in 38 of 42 subjects (90%) with capsaicin titration and in one of 42 (2%) with nocebo. The median dosage required to induce moderate pain for at least 5min was two capsules (interquartile range 1-3) and the median gastric pain intensity was 47 (41-53). The median duration of moderate pain was 8min (5-12). Moderate pain was successfully reproduced with capsaicin in all subjects on study days 2 and 3, with an excellent Cronbach reliability coefficient of >0.8.

CONCLUSIONS & INFERENCES

Standardized gastric pain can be conveniently achieved in a majority of healthy subjects using a simple oral capsaicin titration, with minimal adverse events. The between-test reproducibility is high and nocebo responses are negligible. This technique stimulating a multimodal physiological pathway will be useful in the investigation of sensory changes in FGIDs, including functional dyspepsia.

Measurement of gastric accommodation: a reappraisal of conventional and emerging modalities

Impaired gastric accommodation is an important cause of functional dyspepsia. Currently available tests that evaluate gastric accommodation provide relevant physiological information, but they pose technical difficulties and their clinical impact remains controversial. Gastric barostat remains the gold standard, but it is an invasive procedure. In recent years, emerging modalities including single photon emission computed tomography (SPECT), three-dimensional ultrasound and magnetic resonance imaging have been developed to measure gastric volumes and hold promise as alternative methods of assessing gastric accommodation non-invasively. Studies are underway to validate these techniques with recent data proving the performance characteristics of SPECT. The non-invasive nutrient drink test measures satiety scores as a surrogate marker of gastric accommodation and remains controversial. More recently, intragastric monitoring has been proposed as yet another non-invasive modality to assess gastric accommodation. Each of these different modalities brings its associated advantages and disadvantages, as is discussed in this review. Ongoing studies to validate these new techniques are in progress and are likely to lead to further progress in neurogastroenterology.

Intragastric pressure during food intake: a physiological and minimally invasive method to assess gastric accommodation

BACKGROUND

The stomach relaxes upon food intake and thereby provides a reservoir while keeping the intragastric pressure (IGP) low. We set out to determine whether we could use IGP as a measurement for stomach accommodation during food intake.

METHODS

In fasted healthy volunteers (n = 7-17) a manometer and an infusion catheter were positioned in the proximal stomach. After a stabilization period a nutrient drink was intragastrically infused at 15, 30 and 60 mL min(-1). To investigate the effect of impaired accommodation the effect of N(G)-monomethyl-L-arginine (L-NMMA) was examined. The volunteers scored satiation until maximum, when the experiment ended. The IGP was presented as a change from baseline (mean ± SEM) and compared with repeated measures anova.

KEY RESULTS

Independent on the ingestion speed, the IGP decreased initially and gradually increased thereafter. Volunteers scored maximal satiation after 699 ± 62, 809 ± 90 and 997 ± 120 mL nutrient drink infused (15, 30 and 60 mL min(-1) respectively; P < 0.01). Maximum IGP decrease was 3.4 ± 0.5 mmHg after 205 ± 28 mL, 5.1 ± 0.7 mmHg after 212 ± 46 mL, and 5.2 ± 0.7 mmHg after 296 ± 28 mL infused volume [15, 30 and 60 mL min(-1) respectively; not significant (ns)]. Post hoc analysis showed significant correlations between IGP and satiation score increase. During L-NMMA infusion IGP was significantly increased while subjects drank significantly less (816 ± 91 vs 1032 ± 71 mL; P < 0.005). Interestingly, the correlation between IGP increase and satiation score increase did not differ after L-NMMA treatment.

CONCLUSIONS & INFERENCES

The IGP during nutrient drink ingestion provides a minimally invasive alternative to the barostat for the assessment of gastric accommodation. These findings furthermore indicate that IGP is a major determinant of satiation.

The Reproducibility of Tc-Pertechnetate Single Photon Emission Computed Tomography (SPECT) for Measurement of Gastric Accommodation in Healthy Humans: Evaluation of the Test Results Performed at the Same Time and Different Time of the Day

Background/Aims

Technetium-99m (^99mTc)-pertechnetate single photon emission computed tomography (SPECT) allows non-invasive measurement of gastric accommodation (GA) and has been reported to provide the results comparable to the gold standard barostat. The reproducibility of the test when it is performed at different time of the day is not known. The aim of this study was to assess the reproducibility of GA measurement by ^99mTc-pertechnetate SPECT at the same and different time of the day.

Methods

Three GA studies were performed in each of 20 healthy volunteers (9 males, age 35 ± 9 years), 2 studies in the morning and 1 study in the afternoon. Each study was performed on separate days at least 3 days apart, in random order. The fasting gastric scintigraphy images were acquired using SPECT at 30 minutes after iv ^99mTc-pertechnetate. Then, the scintigraphic images were acquired 50 minutes after liquid meal (250 mL, Ensure®) ingestions. Gastric volumes were calculated from transaxial gastric images using Image J software. The GA was defined as the maximum postprandial gastric volume minus fasting gastric volume.

Results

GA measurement by SPECT show good reproducibility at both the same and different time of the day. The intraclass correlation coefficients of GA results for the same time, the first different time and the second different time studies were 0.681, 0.630 and 0.774, respectively, and the intra-subject coefficients of variation were 13.9%, 14.1% and 8.7%, respectively.

Conclusions

GA measurement by ^99mTc-pertechnetate SPECT shows good reproducibility at both the same and different time of the day. This result suggests that the schedule time does not appear to extremely affect the gastric accommodation value.

Functional dyspepsia

Dyspepsia is a common term used for a heterogeneous group of abdominal symptoms. Functional dyspepsia (FD) is the focus of this review. The 2006 Rome III criteria defined FD and its subgroups, postprandial distress syndrome (PDS) and epigastric pain syndrome (EPS). FD is a very common condition with a high prevalence throughout the world, adversely affecting the quality of life of patients. The pathophysiology of FD has been under investigation during the past two decades. Multiple mechanisms such as abnormal gastric emptying, visceral hypersensitivity, impaired gastric accommodation, and central nervous system factors are likely involved. Several tests are available for the assessment of various physiologic functions possibly involved in the pathogenesis of FD, and some of these could be used in clinical practice, helping to understand the abnormalities underlining patients' complaints. Currently, the possibilities of pharmacological therapy for FD are still limited, however, experience of using prokinetics, tricyclic antidepressants, selective serotonin-reuptake inhibitors (SSRIs), proton-pump inhibitors (PPIs), and several alternative techniques has been accumulated. The different combinations of alterations in physiologic gastrointestinal and central nervous system functions result in the very heterogeneous nature of FD so combined approaches to these patients could be beneficial in challenging cases.

Role of chemical stimulation of the duodenum in dyspeptic symptom generation

The response to chemical stimuli such as acid, nutrients, and capsaicin at the level of the duodenum is increasingly recognized as important in the etiology of dyspeptic symptoms. Increased duodenal acid exposure has been reported for patients with dyspeptic symptoms. Duodenal hypersensitivity to acid and the enhancing effect of duodenal acid on gastroduodenal mechanosensitivity may also contribute to dyspeptic symptom generation. Serotonergic signaling pathways may be involved in acid-induced dyspeptic symptoms. As for nutrients, lipid has been unequivocally shown to have a function in the pathogenesis of dyspeptic symptoms. Cholecystokinin (CCK) is an important mediator of the effects of duodenal lipid on gastroduodenal sensorimotor activities. It is unclear whether CCK hypersecretion or hypersensitivity to CCK is responsible for symptoms in dyspeptic patients. The presence of capsaicin in the duodenum evokes symptoms and affects gastric sensorimotor function. In patients with dyspepsia, capsaicin-induced symptoms appeared to occur earlier and to be more severe, however the effects of duodenal infusion and putative consequent gastric sensorimotor abnormalities have not been examined. Capsaicin activates transient receptor potential ion channel of the vanilloid type I, which can also be activated and sensitized by acid. The interaction between the different chemical stimuli is complex and has not yet been studied in patients with dyspeptic symptoms. In conclusion, the mechanisms underlying an enhanced response to duodenal chemical stimulation in patients with dyspeptic symptoms are partially understood. At the level of the duodenum, abnormalities may exist in stimulus intensity, mucosal mRNA expression, biosynthesis, release, or inactivation of mucosal mediators, or receptor expression on afferent nerve endings. Elucidation of the abnormalities involved will provide a basis for rational treatment of dyspeptic symptoms.

Gastrointestinal targets of appetite regulation in humans

The aim of this paper is to describe and discuss relevant aspects of the assessment of physiological functions - and related biomarkers - implicated in the regulation of appetite in humans. A short introduction provides the background and the present state of biomarker research as related to satiety and appetite. The main focus of the paper is on the gastrointestinal tract and its functions and biomarkers related to appetite for which sufficient data are available in human studies. The first section describes how gastric emptying, stomach distension and gut motility influence appetite; the second part describes how selected gastrointestinal peptides are involved in the control of satiety and appetite (ghrelin, cholecystokinin, glucagon-like peptide, peptide tyrosin-tyrosin) and can be used as potential biomarkers. For both sections, methodological aspects (adequacy, accuracy and limitation of the methods) are described. The last section focuses on new developments in techniques and methods for the assessment of physiological targets involved in appetite regulation (including brain imaging, interesting new experimental approaches, targets and markers). The conclusion estimates the relevance of selected biomarkers as representative markers of appetite regulation, in view of the current state of the art.