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Background: Gastric fluid plays a key role in food digestion and drug dissolution, therefore, the amount of gastric fluid present in a fasted state may influence subsequent digestion and drug delivery. We aimed to describe intra‐ and interindividual variation in fasted gastric content volume (FGCV) and to determine the association with age, sex, and body size characteristics. Methods: Data from 24 MRI studies measuring FGCV in healthy, mostly young individuals after an overnight fast were pooled. The analysis included 366 participants who had up to 6 repeated measurements, with a total of 870 measurements. Linear mixed model analysis was performed to calculate intra‐ and interindividual variability and to assess the effects of age, sex, weight, height, weight*height as a proxy for body size, and body mass index (BMI). Results: FGCV ranged from 0 to 156 mL, with a mean (± SD) value of 33 ± 25 mL. The overall coefficient of variation within the study population was 75.6%, interindividual SD was 15 mL, and the intraindividual SD was 19 mL. Age, weight, height, weight*height, and BMI had no effect on FGCV. Women had lower volumes compared to men (MD: −6 mL), when corrected for the aforementioned factors. Conclusion: FGCV is highly variable, with higher intraindividual compared to interindividual variability, indicating that FGCV is subject to day‐to‐day and within‐day variation and is not a stable personal characteristic. This highlights the importance of considering FGCV when studying digestion and drug dissolution. Exact implications remain to be studied. [ABSTRACT FROM AUTHOR]

Background/Aims: Pulmonary aspiration of gastric content is a serious perioperative complication. The objective of this prospective study was to assess the relationship between the gastric volumes suctioned endoscopically and quantitative (antral cross‐section area) and qualitative (empty vs. nonempty) examination of the gastric antrum. Furthermore, the study aimed to determine the best antral cross‐section area cutoff value for a truly empty antrum in infants. Methods: This study was performed in a pediatric gastrointestinal endoscopy unit. Antral sonography was performed in supine and right lateral decubitus positions in 46 fasted infants prior to upper gastrointestinal endoscopic evaluation. Antral cross‐sectional area measurements in both positions and qualitative evaluation of the antrum (according to a three‐point grading system) were recorded. Gastric contents were endoscopically suctioned and measured. Results: Forty‐six patients (aged under 24 months) were included. According to the three‐point qualitative grading system, 76.1% of patients were classified as grade 0. The best cutoff value for the antral cross‐section area in the right lateral decubitus position, indicating an empty antrum, was determined to be 2.40 cm2. At this specific cutoff value, the sensitivity was 100%, the specificity was 68.6%, and the negative predictive value was 100%. Conclusions: Gastric ultrasonography can confirm an empty or nearly empty stomach in healthy infants. [ABSTRACT FROM AUTHOR]

Background: Liberal fasting regimens, which support clear fluid intake up to 1 h before surgery in children scheduled for elective surgery, are taking their place in guidelines. However, because of the lack of publications that investigate the gastric emptying time in preoperative obese children, the practice of 1‐hour clear fluid fasting in obese children remained at the level of recommendation with weak evidence. Aims: The primary aim was to investigate whether there is a difference in gastric emptying times between obese and non‐ obese children after preoperative intake of 3 mL/kg clear liquid containing 5% dextrose by using ultrasound. Methods: A total of 70 children were included in the study in two groups, 35 obese and 35 non‐obese, aged 6–14 years, who were scheduled for elective surgery. The baseline antral cross‐sectional area measurements of the children in the groups were made using ultrasound. 3 mL/kg 5% dextrose was consumed. Ultrasound was repeated immediately after fluid intake and every 5 min until the antral cross‐sectional area was at the baseline level. Results: The difference in median (IQR [range]) gastric emptying times (minutes) of non‐obese {35 [30.0–45.0 (20–60)]} and obese children {35 [30.0–40.0 (25–60)]} were not statistically significant (median of differences 0.0, 95% CI –5.0 to 5.0; p =.563). The antral cross‐sectional area and weight‐adjusted gastric volumes returned to the baseline level within 60 min after the intake of clear liquid with 3 mL/kg 5% dextrose in all children in both groups. Conclusions: Obese and non‐obese children have similar gastric emptying times, and these groups can be offered clear fluids containing 3 mL/kg 5% dextrose 1 h before the surgery. [ABSTRACT FROM AUTHOR]

Background: Emergent obstetrical procedures may require general anaesthesia in parturients at full cervical dilatation or immediately after vaginal birth. This study aimed to determine the prevalence and the predictive factors of higher estimated gastric content in parturients at full cervical dilatation with epidural analgesia and allowed to drink during the labour, and to assess the ability of the antral area measured in the semirecumbent position (SR-CSA) to identify higher estimated gastric content in this setting.Methods: This prospective observational study was conducted between December 2016 and July 2017. Ultrasonographic examination of the antrum was performed at full cervical dilatation, within the hour preceding the beginning of expulsive efforts. Higher estimated gastric content was defined when solid content was observed and/or if the calculated gastric fluid volume was >1.5 mL/kg.Results: Seventeen of 62 parturients (27%) presented higher estimated gastric content. Maximal pain intensity during the last hour of labour and time interval between the insertion of the epidural catheter and ultrasonographic examination were significantly increased in parturients with higher estimated gastric content. The threshold value of the SR-CSA to identify a higher estimated gastric content was 393 mm2 , with sensitivity = 88% and specificity = 87%.Conclusion: Around a quarter of parturients with epidural analgesia and free access to clear fluids during labour presented higher estimated gastric content at full cervical dilatation. The SR-CSA may be of interest for the fast ultrasound assessment of the gastric content status in case of emergent obstetrical procedures at full cervical dilatation. [ABSTRACT FROM AUTHOR]

The article discusses the link between gastric volume and aspiration risk. Topics include the focus of anaesthetic practice on the prevention of aspiration pneumonitis, the lack of non-invasive tool to assess gastric volume in humans, and the call for greater adoption of gastric and other point-of-care ultrasound applications into clinical practice and training of anaesthesiology.

Bedside gastric ultrasonography can be performed reliably by anaesthetists to assess gastric content in the peri-operative period. We aimed to study the relationship between gastric cross-sectional area, assessed by ultrasound, and volumes of clear fluids ingested by pregnant women. We recruited 60 non-labouring third-trimester pregnant women in a randomised controlled and assessor-blinded study. A standardised scanning protocol of the gastric antrum was performed in the 45° semirecumbent and 45° semirecumbent-right lateral positions. Subjects were randomly allocated to drink one out of six predetermined volumes of apple juice (0 ml, 50 ml, 100 ml, 200 ml, 300 ml, 400 ml). Qualitative and quantitative assessments at a baseline period after an 8-h fast, and immediately after the drink, were used to establish the correlation between antral cross-sectional area and volume ingested. A predictive model to estimate gastric volume was developed. Antral cross-sectional area in the semirecumbent right lateral position significantly correlated with the ingested volume (Spearman rank correlation = 0.7; p < 0.0001). A cut-off value of 9.6 cm2 discriminated ingested volumes ≥ 1.5 ml.kg-1 with a sensitivity of 80%, a specificity of 66.7%, and an area under the curve of 0.82. A linear predictive model was developed for gastric volume based only on antral cross-sectional area (Volume (ml) = -327.1 + 215.2 × log (cross-sectional area) (cm2 )). We conclude that in pregnant women in the third trimester of gestation, the antral cross-sectional area correlates well with volumes ingested, and this cut-off value in the semirecumbent right lateral position discriminates high gastric volumes. [ABSTRACT FROM AUTHOR]

Ultrasound examination of the gastric antrum allows reliable assessment of gastric contents and volume. Postoperative assessment of gastric contents before recovery from anaesthesia could help the physician to choose the most appropriate extubation technique after surgery in children. In this prospective observational study, we assessed whether significant changes occurred in gastric contents during the intra-operative period in children undergoing elective ear, nose and throat (ENT) surgery. Children aged between six months and 16 years were recruited consecutively. Ultrasound examination of the antrum was performed before induction of anaesthesia and at the end of surgery before tracheal extubation, and included quantitative and qualitative assessment of gastric contents. The mean (SD) gastric volume was 0.28 (0.30) ml.kg-1 before surgery and 0.27 (0.30) ml.kg-1 after surgery, p = 0.82. No solid contents were identified in the antrum, and the gastric volume was < 1.5 ml.kg-1 in all patients during both ultrasound examinations. Our results suggest that, after elective ENT surgery, children are not at risk of a full stomach before tracheal extubation, and that pulmonary aspiration of blood that may occur after elective ENT surgery is probably not related to regurgitation of ingested blood from the stomach. [ABSTRACT FROM AUTHOR]

We aimed to measure gastric antral cross-sectional area with ultrasound and estimate the gastric volume of 300 patients before unplanned surgery, fasted for at least six hours. Measurements were successfully recorded in 263 semi-recumbent patients. The median (IQR [range]) area was 333 (241-472 [28-1803]) mm2 and the mean (SD) estimated volume was 45.8 (34.0) ml. The area exceeded 410 mm2 in 92/263 (35%) measurements. Body mass index and morphine administration were associated with larger gastric areas on multivariable linear regression analysis, with beta coefficient (95%CI) 0.02 (0.01-0.04), p = 0.01, 0.23 (0.01-0.46), p = 0.04, respectively. Fasting time was not associated with gastric area and therefore could not substitute for ultrasound measurements in this cohort. [ABSTRACT FROM AUTHOR]

Background: Emergency situations and conditions with impaired gastric emptying enhance the risk of perioperative pulmonary aspiration due to increased residual gastric contents volume (GCV). Gastric ultrasonographic (US) measurement of the gastric antral cross-sectional area (CSA) has been proposed to estimate preanesthetic GCV. However, only few healthy children and fasted pediatric patients have been investigated so far, predicting GCV with considerable imprecision. This study aimed to compare GCV assessed by US in different patient positions for measuring CSA, using magnetic resonance imaging (MRI) as reference, and to evaluate its potential as diagnostic test. Methods: Healthy volunteer children were examined in a crossover design on 2 days. After baseline examination, they received a light breakfast, followed by 7 ml·kg-1 clear fluid after 2 or 4 h. Gastric emptying was examined with MRI over 4 or 6 h, respectively. US was performed immediately after MRI in right lateral decubital (RLD) and supine with upper body elevated (SUBE) positions. Correlation coefficients (Pearson R; 95%CI) between CSA and body weight corrected GCV (GCVw) as determined by MRI volumetry were calculated. Data are presented as median (range). Results: Eighteen children aged 9.8 (6.8-12.2) years had 72 US examinations completed. CSA was 401 (101-1311) mm² and 271 (118-582) mm², and R between CSA and GCVw was 0.76 (0.76-1) and 0.57 (0.41-0.88) for the RLD and SUBE positions, respectively. The corresponding GCVw was 2.1 (0.1-13.8) ml·kg-1. A linear regression model from RLD was similar to one previously derived. Bland-Altman analysis and ROC plots are presented. Conclusion: CSA correlated with GCVw in healthy children over a wide range of gastric filling, with the RLD position clearly superior to the SUBE position, confirming a previously derived formula. Although direct calculation of GCVw is imprecise, this technique has the potential to become a diagnostic risk assessment test. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background Using an experimental model of colonic gas infusion, we previously showed that the abdominal walls adapt to its content by an active phenomenon of abdominal accommodation. We now hypothesized that abdominal accommodation is a physiological phenomenon, and aimed to confirm that it can be induced by ingestion of a meal; a secondary aim was to determine whether the response to gut filling is region-specific. Methods In healthy subjects ( n = 24) a nutrient test meal was administered until tolerated at a rate of 50 mL min−1. Electromyographic (EMG) activity of the anterior wall (upper and lower rectus, external and internal oblique) was measured via four pairs of surface electrodes, and EMG activity of the diaphragm via intraluminal electrodes on an esophageal tube. To address the secondary aim, the response to gastric filling was compared with that induced by colonic filling (1440 mL 30 min−1 anal gas infusion; n = 8). Key Results Participants tolerated 927 ± 66 mL of meal (450-1500 mL). Meal ingestion induced progressive diaphragmatic relaxation (EMG reduction by 16 ± 2%; P < 0.01) and selective contraction of the upper abdominal wall (24 ± 2% increase in activity of the upper rectus and external oblique; P < 0.01 for both), with no significant changes in the lower rectus (4 ± 2%) or internal oblique (5 ± 3%). Colonic gas infusion induced a similar response, but with an overall contraction of the anterior wall. Conclusions & Inferences Meal ingestion induces a metered and region-specific response of the abdominal walls to accommodate the volume load. Abnormal abdominal accommodation could be involved in postprandial bloating. [ABSTRACT FROM AUTHOR]

The endocannabinoid system is associated with food intake. We hypothesized that genes regulating cannabinoids are associated with obesity. Genetic variations in fatty acid amide hydroxylase (FAAH) and cannabinoid receptor 1 (CNR1) are associated with satiation and gastric motor function. In 62 overweight or obese adults of European ancestry, single nucleotide polymorphisms of rs806378 (nearest gene CNR1) and rs324420 (nearest gene FAAH) were genotyped and the associations with gastric emptying (GE) of solids and liquids, gastric volume (GV), and satiation [maximum tolerated volume (MTV) and symptoms after Ensure nutrient drink test] were explored using a dominant genetic model, with gender and BMI as covariates. rs806378 CC genotype was associated with reduced fasting GV (210.2 ± 11.0 mL for CC group compared to 242.5 ± 11.3 mL for CT/TT group, P = 0.031) and a modest, non-significant association with GE of solids ( P = 0.17). rs324420 genotype was not associated with alterations in gastric motor functions; however, there was a difference in the Ensure MTV (1174.6 ± 37.2 mL for CC group compared to 1395.0 ± 123.1 mL for CA/AA group, P = 0.046) suggesting higher satiation with CC genotype. Our data suggest that CNR1 and FAAH are associated with altered gastric functions or satiation that may predispose to obesity. [ABSTRACT FROM AUTHOR]

Objective: Genetic variation in transcription factor 7-like 2 (TCF7L2), a regulator of proglucagon processing, is reproducibly associated with type 2 diabetes. GLP-1 alters gastric function and increases satiation. Hypothesis: Genetic variation in TCF7L2 is associated with satiation, gastric motor function, and GLP-1 concentrations. Methods: In 62 adults, a single nucleotide polymorphism (SNP) of TCF7L2 (rs7903146) was genotyped and associations with gastric emptying (GE) of solids and liquids, gastric volume (GV), and satiation (maximum tolerated volume and symptoms after nutrient drink test) were explored using a dominant genetic model, with gender and BMI as covariates. In 50 of the participants, we also measured plasma GLP-1 during fasting and after ingestion of a nutrient drink. Results: Presence of the T allele compared to CC genotype in rs7903146 SNP of the TCF7L2 gene was associated with reduced fasting GV (246.3 ± 11.4 mL for CC group, compared to 215.7 ± 11.4 mL for CT/TT group, p = 0.05) and accelerated GE t 1/2 of liquids (26.3 ± 2.0 minutes for CC compared to 17.7 ± 1.4 for CT/TT, p < 0.005). There was no significant association of rs7903146 SNP with GE of solids, gastric accommodation, satiation, fasting, or postprandial GLP-1. Conclusion: Our data suggest TCF7L2 is associated with altered gastric functions that may predispose to obesity. Clin Trans Sci 2011; Volume 4: 183-187 [ABSTRACT FROM AUTHOR]

Background The intragastric balloon, filled with air or liquid is used before elective bariatric surgery because its efficacy is limited. This might be the consequence of altered gastric functions. Therefore, we aimed to investigate, in an animal model, the changes in gastric motility and emptying induced by long-term insertion of a balloon used for weight reduction. Methods Ten Göttingen mini-pigs were allocated into two groups with and without an intragastric balloon for 5 months. Balloons were inserted under endoscopy during general anesthesia and were filled with 350 mL of air. Gastric emptying was evaluated by scintigraphy. Gastric volume was measured by single photon emission computed tomography and proximal gastric compliance obtained using an electronic barostat. Changes in vagal tone were assessed by heart rate variability (HRV). Key Results After balloon insertion, gastric volume was significantly increased (2047 ± 114.8 cm3 after vs 1674 ± 142.5 cm3 before insertion, P < 0.05). Gastric compliance was also larger in balloon group (219 ± 23.4 mL mmHg−1 in balloon vs 168 ± 7.7 mL mmHg−1 in control group). Gastric emptying was reduced after insertion of the balloon ( T1/2 = 204 ± 28.8 min vs 159 ± 25.4 before vs after insertion). High frequency components of the spectral analysis of HRV, representing vagal tone, were increased in balloon group. Conclusions & Inferences The proximal stomach was enlarged after the insertion of a balloon in the stomach as a consequence of an increased gastric compliance. This change in compliance was probably causative for a reduction in gastric emptying rate of solids. These alterations were associated with increased vagal tone. [ABSTRACT FROM AUTHOR]

This review focuses on the gastrointestinal tract's control of appetite and interventions directed to the gut that are effective in the treatment of obesity. It examines the evidence linking gut hormones to the control of both appetite and upper gastrointestinal motility, the evidence that stomach function is altered and contributes to satiation in obesity and outlines the principles of therapy for obesity which are directed at the gastrointestinal tract. These therapies impair fat absorption or alter stomach functions through pharmacological, device, endoscopic, or surgical approaches. Gastroenterologists need to understand the role of factors controlling appetite in order to effectively manage the increasing number of obese patients and the ways the gut function may be altered as a result of the treatments and their complications. [ABSTRACT FROM AUTHOR]

To compare gastric volume responses to ingestion of isocaloric liquid or mixed (solid–liquid) meals and document the intra- and interindividual reproducibility of gastric volume measurement using single photon emission computed tomography (SPECT) imaging after i.v.99mTc-pertechnetate.Eight healthy volunteers performed two studies at least 9 months apart. Gastric volumes were measured after a 317 kcal liquid nutrient meal. Within 2 weeks of the second liquid meal study, participants performed a third study, ingesting an isocaloric mixed meal. The order of the mixed and second liquid meals was randomized; Bland–Altman plot displayed data on repeated studies with liquid meal and pairedt-test compared gastric volumes after mixed or liquid isocaloric meals.Fasting and postprandial gastric volumes associated with the two liquid meals were not significantly different; inter- and intra-individual coefficients of variation were 13 and 13.8%. In response to the mixed meal, there was a lower absolute postprandial volume and lower change in gastric volume over fasting volume compared with the response to the liquid meal (P = 0.0001).The SPECT measurement of gastric volumes in response to a nutrient liquid meal is reproducible. The magnitude of the volume response is greater after the liquid meal compared with the isocaloric mixed meal. [ABSTRACT FROM AUTHOR]