Term pregnant patients have similar gastric volume to non-pregnant females: a single-centre cohort study.

BACKGROUND: The physiological changes of pregnancy can increase the risk of peri-partum pulmonary aspiration. There is limited objective information regarding gastric volumes in pregnant patients. The aim of this cohort study was to characterise prospectively the range of gastric-fluid volume in term non-labouring pregnant patients compared with a historical cohort of non-pregnant females. METHODS: Fasted non-labouring term pregnant patients scheduled for elective Caesarean delivery underwent a standardised gastric ultrasound examination. Gastric content was evaluated qualitatively (type of content), semi-quantitatively (Perlas grades), and quantitatively (volume). The antral cross-sectional area and volume were compared with those of a retrospective cohort of non-pregnant females from the same institution. Descriptive statistics were used to describe the central tendency through mean and median values. Dispersion was evaluated with standard deviation and inter-quartile range, and the higher end of the distribution as 95th percentile. RESULTS: Non-labouring pregnant (59) and non-pregnant (81) subjects were studied. The range of estimated total gastric-fluid volume (P=0.96) and volume per body weight (P=0.78) was not significantly different between cohorts. An estimated volume of 115 ml (102-143) vs 136 ml (106-149) and volume per body weight of 1.4 ml kg-1 (1.2-2.8) vs 2.0 ml kg-1 (1.5-2.7) corresponded to the 95th percentile (95% confidence interval) values in the pregnant and non-pregnant cohort, respectively. CONCLUSIONS: Baseline gastric volume of non-labouring pregnant patients at term is not significantly different from that of non-pregnant females. This information will be helpful to interpreting findings of gastric point-of-care ultrasound in obstetric patients.

Preoperative Assessment of Ultrasonographic Measurement of Antral Area for Gastric Content.

BACKGROUND Pulmonary aspiration of the gastric contents is a serious perioperative complication. The aim of this study was to evaluate the efficacy of portable ultrasonography in the preoperative evaluation of the gastric contents of patients. The secondary aim was to examine the relationship between gastric antrum cross-sectional area and age and body mass index (BMI). MATERIAL AND METHODS This single-center, prospective, cross-sectional study included 120 patients who underwent surgery. Measurements the gastric antral cross-sectional areas and quantitative and qualitative measurements of the stomach were taken by ultrasonography guidance in all patients. RESULTS With the patient in a supine position, the mean gastric antrum cross-sectional area was found to be 3.4±2.43 cm² (range, 0.79-17.3 cm²). As the number of hours of fasting increased, the gastric antral cross-sectional area statistically significantly decreased (P<0.05). Increased age and BMI values were determined to increase the gastric antrum cross-sectional area in a linear correlation; r=0.209, P<0.05 and r=0.252, P=0.05, respectively. It was determined that 20.8% of the patients exceeded the high-risk stomach antral cutoff cross-sectional area that was defined as 340 mm2 in patients fasting for at least 8 hours. CONCLUSIONS It was determined that bedside ultrasonography is a useful, non-invasive tool in the determination of gastric content and volume. A significant proportion of surgical patients may not present with an empty stomach despite the recommended fasting protocols.

Gastric ultrasound in the third trimester of pregnancy: a randomised controlled trial to develop a predictive model of volume assessment.

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.

Changes in qualitative and quantitative ultrasound assessment of the gastric antrum before and after elective caesarean section in term pregnant women: a prospective cohort study.

Ultrasound measurement of the antral cross-sectional area allows a quantitative estimate of gastric contents in non-pregnant adults, but this relationship may be affected by compression of the stomach exerted by the gravid uterus during pregnancy. This study aimed to assess differences in quantitative (Perlas score) and qualitative (antral cross-sectional area) ultrasound assessments of the gastric antrum performed immediately before and after caesarean section. Forty-three women having elective caesarean section performed under spinal anaesthesia were studied in the semirecumbent and semirecumbent-right lateral positions. Thirty-nine women showed no change in stomach contents using the Perlas score between the two measurement periods; four women showed a change, but by one grade only. The median (IQR [range]) antral cross-sectional area was 323 (243-495 [103-908]) mm2 before, and 237 (165-377 [112-762]) mm2 after, caesarean section in the semirecumbent position (p = 0.001); the comparable values in the semirecumbent-right lateral position were 418 (310-640 [161-1238]) mm2 and 362 (280-491 [137-1231]) mm2 (p = 0.09). The distance between the skin and the antrum, and the aorta and the antrum, decreased significantly in both positions after surgery. We suggest that our results indicate that stomach contents remain largely unchanged in women having elective caesarean section, but antral cross-sectional area decreases, especially in the semirecumbent position, related to a change in the position of the stomach within the abdomen. This implies that the relationship of antral cross-sectional area to volume of stomach contents, which has been determined for non-pregnant subjects, may not apply in term pregnant women.

Gut morphology and hepatic oxidative status of European sea bass (Dicentrarchus labrax) juveniles fed plant feedstuffs or fishmeal-based diets supplemented with short-chain fructo-oligosaccharides and xylo-oligosaccharides.

The effects of short-chain fructo-oligosaccharides (scFOS) and xylo-oligosaccharides (XOS) on gut morphology and hepatic oxidative status were studied in European sea bass juveniles weighing 60 g. Fish were fed diets including fishmeal (FM diets) or plant feedstuffs (PF diets; 30 FM:70 PF) as main protein sources (control diets). Four other diets were formulated similar to the control diets but including 1 % scFOS or 1 % XOS. At the end of the trial, fish fed PF-based diets presented histomorphological alterations in the distal intestine, whereas only transient alterations were observed in the pyloric caeca. Comparatively to fish fed FM-based diets, fish fed PF diets had higher liver lipid peroxidation (LPO), superoxide dismutase (SOD) and catalase (CAT) activities, and lower glutathione peroxidase, glutathione reductase and glucose 6-phosphate dehydrogenase activities. In fish fed the PF diets, prebiotic supplementation decreased SOD activity and XOS supplementation further decreased CAT activity. In fish fed the FM diets, XOS supplementation promoted a reduction of all antioxidant enzyme activities. Overall, dietary XOS and scFOS supplementation had only minor effects on gut morphology or LPO levels. However, dietary XOS reduced antioxidant enzymatic activity in both PF and FM diets, which indicate a positive effect on reduction of hepatic reactive oxygen species production.

Ultrasonographic evaluation of gastric content during labour under epidural analgesia: a prospective cohort study.

BACKGROUND: Women in labour are considered at risk of gastric content aspiration partly because the stomach remains full before delivery. Ultrasonographic measurement of antral cross-sectional area (CSA) is a validated method of gastric content assessment. Our aim was to determine gastric content volume and its changes in parturients during labour under epidural analgesia using bedside ultrasonography. METHODS: The cut-off value corresponding to an increased gastric content was determined by ultrasound measurement of antral CSA in six pregnant women in late pregnancy before and after ingestion of 250 ml of non-clear liquid. Antral CSA was then measured twice in 60 parturients who presented in spontaneous labour: when the anaesthesiologist was called for epidural analgesia catheter placement, and at full cervical dilatation. Patient-controlled epidural analgesia was performed with a solution of ropivacaine and sufentanil. RESULTS: After liquid ingestion, antral CSA (mm(2)) increased from 90 (range, 80-151) to 409 (range, 317-463). A CSA of 320 was taken as cut-off value. The feasibility rate of antral CSA determination was 96%. CSA decreased from 319 [Q1 158-Q3 469] to 203 [Q1 123-Q3 261] during labour (P=2×10(-7)). CSA was >320 in 50% of parturients at the beginning of labour vs 13% at full cervical dilatation (P=0.006). CONCLUSIONS: Bedside ultrasonographic antral CSA measurement is feasible in pregnant women during labour and easy to perform. The observed decrease in antral CSA during labour suggests that gastric motility is preserved under epidural anaesthesia. The procedure could be used to assess individual risk of gastric content aspiration during labour.

Clinical assessment of the ultrasonographic measurement of antral area for estimating preoperative gastric content and volume.

BACKGROUND: This prospective observational study aimed to assess the feasibility and performance of the ultrasonographic measurement of antral cross-sectional area (CSA) for the preoperative assessment of gastric contents and volume in adult patients and for the diagnosis of risk stomach (defined by the presence of solid particles and/or gastric fluid volume >0.8 ml/kg). METHODS: A preoperative ultrasonographic measurement of the antral CSA was performed for each patient by a physician (L.B.) blinded to the history of the patient. Immediately after tracheal intubation, an 18-French multiorifice Salem tube was inserted and gastric contents were aspirated in five different patient positions; during this time, the patient's epigastrium was massaged and the tube was moved backward and forward in the stomach. The relationship between the antral area and the volume of aspirated gastric contents was analyzed, as was the performance of ultrasonographic measurement of antral area for the diagnosis of risk stomach. RESULTS: The measurement of antral CSA was performed on 180 of 183 patients. A significant positive relationship between antral CSA and aspirated fluid volume was found. The cutoff value of antral CSA of 340 mm(2) for the diagnosis of risk stomach was associated with a sensitivity of 91% and a specificity of 71%. The area under the receiver operating characteristic curve for the diagnosis of risk stomach was 90%. CONCLUSIONS: The ultrasonographic measurement of antral CSA could be an important help for the anesthesiologist in minimizing the risk of pulmonary aspiration of gastric contents due to general anesthesia.

Relation between postprandial satiation and antral area in normal subjects.

The factors influencing appetite in humans are poorly understood. There is a weak relation between appetite and gastric emptying in normal subjects. Recent studies have shown that fasting and postprandial antral areas increase in patients with functional dyspepsia compared with normal subjects. We evaluated the hypothesis that antral area, and hence antral distention, is a significant determinant of postprandial fullness. Fourteen normal subjects had simultaneous measurements of gastric emptying by scintigraphy and antral area by ultrasound after ingestion of 350 mL 20% glucose. Fullness and hunger were assessed by visual analog scales. Measurements of the gastric-emptying half time (t1/2) by scintigraphy and ultrasound were not significantly different (129.6 +/- 11.8 min compared with 115.6 +/- 11.4 min). Fullness increased (P < 0.001) and hunger decreased (P < 0.001) after the drink. Both fullness and the magnitude of the increase in fullness after the drink were related to antral area (r > 0.56, P < 0.05), the increase in antral area (r > 0.59, P < 0.05), and the scintigraphic content of the distal stomach (r > 0.57, P < 0.05), but not to the ultrasound or scintigraphic t1/2 values. In contrast, hunger and the magnitude of the decrease in hunger after the drink were not related to either antral area, the increase in antral area, or the rate of gastric emptying. We conclude that postprandial fullness, but not hunger, was closely related to antral distention in normal subjects.

Normal histology of the stomach.

The normal microscopic and gross morphologic features of the stomach are described. Emphasis is given to mucosal anatomy and the recognition of minor alterations seen in disease that may be identified on an endoscopic biopsy. Advice is given in the interpretation of biopsy artefact that may present diagnostic problems. The various types of gastric metaplasia are discussed both in relation to altered morphology and to changes in mucin histochemistry.

Definition of gastroduodenal junction in healthy subjects.

To study the appearance and distribution of the normal mucosa at the gastroduodenal junction in man, 14 specimens of normal mucosa, eight obtained during pylorplasty, and "relatively" normal specimens from the distal stomach and whole duodenum were examined microscopically. Three histologically distinct types of normal duodenal mucosa were found at this junction. These were termed antral type duodenal mucosa, transitional type duodenal mucosa (which is also referred to as gastric surface epithelial metaplasia), and jejunal type duodenal mucosa. Antral type duodenal mucosa appeared as a series of finger-like processes 1-3 mm long, circumferentially located around the junction of the antrum and duodenum; transitional type duodenal mucosa extended 2-3 mm beyond this; and the rest of the mucosa was jejunal type duodenal mucosa. The mucosa of the pyloric antrum can therefore lie adjacent to antral type duodenal mucosa, or adjacent to either of the components of transitional type duodenal mucosa.

Sequential use of the PAP and immunogold staining method for the light microscopical double staining of tissue antigens.

Double immunoperoxidase staining using different couplers can give various combinations of colours on a single tissue section to achieve a comparable picture of different antigens. However, the colour combinations achieved to date are not entirely satisfactory. A double immunostaining procedure is introduced here, combining the peroxidase anti-peroxidase (PAP) and immunogold staining (IGS) methods. The IGS method is a new, simple, sensitive and reliable approach to immunostaining at the light microscopic level. It was carried out in three ways. Firstly, a two-step method was used in which the second layer was goat anti-rabbit IgG absorbed onto gold particles (GAR/Au20). Secondly, a three-step method was employed where the second layer was unlabelled goat anti-rabbit IgG and the third layer was a rabbit antibody to peroxidase absorbed onto the gold particles (RAP/Au20) and acting as a gold-labelled IgG antigen. The third method combined the first two methods using GAR/Au20 as th second layer and RAP/Au20 as the third layer which increased the amount of bound gold and enhanced the red colour, providing a better picture. The use of gold-labelled antibodies in double immunostaining has great potential value for many studies including that of the diffuse neuroendocrine system of the gut.

Morphological examination of the termination pattern of substance P-immunoreactive nerve fibers in human antral mucosa.

The termination pattern of substance P (SP)-containing axons in human antral mucosa was examined using immunohistochemical techniques at the light and electron microscopic level. SP-immunoreactive (IR) axons were found to extend towards the pit region of the glands, where intraepithelial axons were observed. Electron microscopy showed immunostained axon profiles in close contact with the basement membrane of surface mucous cells. Membrane-to-membrane contacts between labeled axons and myofibroblast-like cells were identified, and SP-IR axons that were apposed to the epithelium were also in contact with subjacent myofibroblast-like cells. The anatomical relationship between SP-IR axons and the cells of the muscularis mucosae was investigated by light microscopy. Immunoreactivity for alpha-smooth muscle actin (alpha-sma) was used to visualize the smooth muscle cells, and the alpha-sma-IR cells were found to create a network that surrounded the gastric glands. Immunostained varicose axons ran alongside and in close apposition to the labeled muscle strands. Ultrastructural examination showed close contacts between SP-IR axon profiles and smooth muscle-like cells. In conclusion, SP-containing neurons may be important for sensory and secretomotor functions in the human antral mucosa.

Fat delays emptying but increases forward and backward antral flow as assessed by flow-sensitive magnetic resonance imaging.

Flow has been assessed in the gastric antrum using a velocity-sensitive version of the high-speed magnetic resonance imaging technique, echo planar imaging (EPI). Eight healthy volunteers attended fasted on three separate days and consumed 800 mL of either a 5% glucose (0.2 kcal mL-1), 10% glucose (0.4 kcal mL-1) or an isotonic mixed nutrient meal, Fresubin (1 kcal mL-1, 27.2 g fat). Gastric volumes were obtained at 10-min intervals for 1 h. Flow measurements were performed on a single slice through the antropyloric region 5 and 35 min after meal ingestion. Gastric volumes at 45 min were inversely proportional to the calorie density of the meal with (mean +/- SEM) 89 +/- 10%* of the Fresubin, 64 +/- 5%* of the 10% glucose and 41 +/- 5% of the 5% glucose remaining (*P < 0.005 vs 5% glucose). Substantial forward and backward antral flow was observed after all three meals in the initial 5-min imaging period. AT 35 min flow activity was significantly greater after both the high-calorie meals relative to the 5% meal (total number of flow events: Fresubin = 6.6 +/- 1.7,[symbol: see text] 10% glucose = 9.9 +/- 2.2, [symbol: see text] 5% glucose = 2.5 +/- 0.9,[symbol: see text] P < 0.03,[symbol: see text] P < 0.007 vs 5% glucose, n = 8). Peak forward velocities for the initial phase of emptying tended to be greater for the rapidly emptying 5% meal (5.9 +/- 0.8 cm-1) compared with the Fresubin (3.3 +/- 0.6 cm-1, P < 0.069, n = 8) and the 10% glucose (2.9 +/- 1.0 cm-1, P < 0.068, n = 8) meals. In spite of delayed gastric emptying, high-calorie meals were associated with substantial to and fro movements which may be important for meal tritruration and fat emulsification.

Theophylline and gastric emptying in very low birthweight neonates: a randomised controlled trial.

BACKGROUND: Theophylline treatment causes side effects such as tachycardia, hyperglycaemia, abdominal distension, and vomiting. The latter two are probably the result of delayed gastric evacuation. OBJECTIVE: To study the effect of theophylline on gastric emptying time in preterm infants. PATIENTS: The subjects were 18 premature neonates with a mean (SD) birth weight of 1302 (240) g and a mean (SD) gestational age of 28.7 (1.9) weeks. MAIN OUTCOME MEASURES: In each case, gastric emptying was measured on two occasions: once when the newborns were being treated with theophylline and once when they were not. Half of the cases were randomised to receive theophylline before the initial measurement. The opposite was applied for the rest. Gastric emptying was assessed ultrasonically by measuring the change in antral cross sectional area (ACSA) at regular intervals over 120 minutes. RESULTS: The mean (SD) ACSA half time in the newborns receiving theophylline was 52 (19) minutes compared with 37 (16) minutes in those not receiving theophylline. This difference is significant (p < 0.05). CONCLUSIONS: Treatment with theophylline seems to delay gastric emptying in very low birthweight neonates, and this must be taken into consideration when this drug is used to treat apnoea of prematurity.

A simple method of determining the boundary between the antrum and corpus of the stomach. Part 2. Electric vagal stimulation in dogs.

Our previous work demonstrated that electric vagal stimulation in conjunction with Congo red as a dye-indicator is the faster and more reliable method for delineating the corpus-antral boundary in rats. Based on this finding, our study was extended to a larger animal model, the dog; this study proved the electrical vagal stimulation along with Congo red is a reliable method for adequate demonstration of this corpus-antral boundary. No untoward effect on the cardiac function was observed during stimulation of subdiaphragmatic portion of vagal trunks.

[MR imaging of gastric wall layers in vitro: correlation to thehistologic wall structure]. / Experimentelle Darstellung der Schichten der Magenwand mittels MRT: Korrelation mit demhistologischen Wandaufbau.

PURPOSE: To correlate gastric wall layers visible of MRI with the anatomical structure of the gastric wall. METHODS: After macroscopic preparation 5 x 5 cm post-mortem tissue sections of the gastric antrum were evaluated using a 2.4 Tesla MR unit (Bruker, Ettlingen, Germany). MR imaging consisted of T2-weighted multi-spinecho sequences in longitudinal and axial directions. The specimens then were stained with hematoxylin-eosin for histological examination. After that histological correlation of the gastric wall layers visible on MRI was performed. RESULTS: In all specimens four gastric wall layers could be clearly identified on MRI. The direct comparison of those layers to the histological findings showed the following correlation: 1) intermediate signal = mucosa, 2) hypointense signal = lamina muscularis mucosae, 3) hyperintense signal = submucosa, 4) intermediate signal = muscularis propria. CONCLUSIONS: Gastric wall layers visible on MRI were successfully correlated to the anatomic layers of the gastric wall. This allows us for the first time to classify invasion of gastric carcinoma using high spatial-resolution MR imaging. However, the subserosa and serosa are excluded from this conclusion, because so far a reliable statement concerning the value of MRI to depict these very variable layers is not possible.

A simple method of delineating between the antrum and corpus of the stomach, part 1: A comparative study in rats.

A comparative study was performed in rats to find the fastest and most reliable method for delineating the corpus-antrum boundary using alcohol, betazole and electric vagal stimulation in conjunction with Congo red. This study demonstrated that electric vagal stimulation is the fastest and most reliable method.

Anatomical aspects in ultrasonic endoscopy for the stomach.

Gastric wall structure cannot be visualized neither by conventional ultrasonography nor by endoscopy alone. Using a newly developed ultrasonic endoscope (Olympus GF- UM1 / EUM1 Prototype III) twenty-two patients were examined with the stomach filled with 300-500 cc of de- aired water. Ultrasonographic appearance of the normal gastric wall consists of four layers of different echogenicity. The first inner layer, echogenic, seems to correspond to the mucosa and the submucosa, the 2nd echopoor to the muscularis propria, the 3rd echogenic to the serosa and the 4th echopoor to the subserosal-fat. For a complete exploration of the gastric cavity, starting with the scope near the pylorus and withdrawing it until the fundic region, four positions have been standardized. In the first, the antral region is explored, in the 2nd the antrum and the gastric body, in the 3rd the body and antrum and in the 4th position body and fundic region are visualized. For a satisfactory examination a good filling of the stomach must be achieved; problems in interpretation may arise when the gastric wall is not well distended or when peristaltic waves are present. Promising findings have been obtained in 3 cases of cancer involvement of the stomach. No complications were encountered during this study.

[Clinical anatomy of gastroduodenal transition]. / Klinicheskaia anatomiia gastroduodenal'nogo perekhoda.

Individual differences of gastroduodenal transition shape, dimensions and structure were studied using histo-topographic preparations from 45 human cadavers, 60 intravital X-ray photographs and findings from 55 endoscopic examinations. The range of differences in the position of gastroduodenal mucosal junction on pyloric duodenal and gastric surfaces, was established. Muscular, muscular-submucosal and muscular-glandular types of gastroduodenal transition were distinguished. The morphological parameters of the differences of pyloric wall shape and dimensions were defined. Endoscopically, the dimension of pyloric orifice was classified as small, medium and large while its shape was described as round, oval, triangular or polygonal. Clinical applications of the data obtained were determined. Gastroduodenal transition is described as a complex, individually variable anatomical structure with clinically significant differences of its major structural components.

[Correlation between the anterior antral branches of the vagus nerve and the antral-fundic boundary in duodenal ulcer].

The distances from the pylorus to the most proximal branch (proximal branch) and the most distal branch (distal branch) of the anterior antral branches were measured in 37 duodenal ulcer patients. The resected specimens were examined histologically to determine the antral-fundic boundary (F-line) and the distance from the pylorus to F-line was calculated. The distances from the pylorus to proximal branch, distal branch and F-line were 7.8 +/- 1.6 cm, 5.1 +/- 1.2 cm, 6.7 +/- 1.4 cm (M +/- SD), respectively. The mucosal area of proximal branch was fundic in 77% and pyloric in 23%. The mucosal area of distal branch was fundic in 14% and pyloric in 86%. There were three types of distribution of anterior antral branches in relation to F-line. In fundic type both proximal and distal branches intersect fundic mucosa. In ordinary type proximal branch intersects fundic mucosa whereas distal branch intersects pyloric mucosa. In pyloric type both proximal and distal branches intersect pyloric mucosa. The numbers of each type were 5(14%), 22(63%) and 8(23%), respectively. In conclusion, selective proximal vagotomy is not indicated for cases of fundic type in which the entire anterior antral branches intersect fundic mucosa.