Evaluation of the 'Sip Til Send' regimen before elective caesarean delivery using bedside gastric ultrasound: A paired cohort pragmatic study.

BACKGROUND: Pre-operative fasting is routinely advocated to avoid pulmonary aspiration. The European Society of Anaesthesiology and Intensive Care (ESAIC) recommends a fasting period of 2 h for liquids before surgery. Liberal drinking policies such as the 'Sip Til Send' are a suggested alternative to maintain hydration before surgery. OBJECTIVES: To compare residual gastric volumes in fully fasted nonlabouring parturients before elective caesarean delivery with the 'Sip Til Send' with water liberal drinking protocol. Our hypothesis was the 'Sip Til Send' would be noninferior to standard fasting at minimising the residual gastric volume immediately before surgery. DESIGN: A paired cohort prospective observational pragmatic study using gastric ultrasound, analysed by an operator blinded to the fasting status of each scan. SETTING: A tertiary maternity hospital in Dublin, Ireland. The study was conducted between January and June 2023. PARTICIPANTS: Pregnant women about to undergo elective caesarean delivery who had followed ESAIC fasting guidelines before admission. INTERVENTIONS: Each participant underwent two pairs (semi-recumbent and the semi-recumbent right lateral positions) of standardised ultrasound examinations of the gastric antrum: the order of these scans was randomised. The first pair of scans occurred on admission before the 'Sip Til Send' protocol commenced, the other pair just before spinal anaesthesia for caesarean delivery, after a variable time following the 'Sip Til Send' protocol. MAIN OUTCOME MEASURE: The primary outcome was the difference in antral cross-sectional area (CSA) between the fully fasted women on admission and the same women after following the 'Sip Til Send' protocol until just before spinal anaesthesia. RESULTS: Fifty-eight women were randomised for the study: 55 and 54 scans in the semi-recumbent position on admission, and 55 and 54 scans in the right lateral position just before spinal anaesthesia. The mean differences (95% CI) in CSA in the semi-recumbent and RL positions were 0.07 (-0.39 to 0.53) cm 2 and 0.04 (-0.60 to 0.68) cm 2 , respectively. Since the of 95% CIs did not cross the predefined noninferiority margin of 0.88 cm 2 , 'Sip Til Send' was noninferior to fully fasting in in terms of the antral CSA. CONCLUSION: The 'Sip Til Send' protocol of liberal hydration with water was noninferior to standard fasting prior to elective caesarean delivery. TRIAL REGISTRY NUMBER: NCT05783427 ClinicalTrials.gov.

Determining residual gastric volume in healthy children using ultrasound.

PURPOSE: Fasting guidelines for children recommend restricting clear fluids for one or two hours before a procedure to reduce pulmonary aspiration. Gastric volumes < 1.5 mL·kg-1 do not seem to present an increased risk of pulmonary aspiration. Our aim was to quantify the time to achieve a gastric volume < 1.5 mL·kg-1 after clear fluid ingestion in children. METHODS: We conducted a prospective observational study in healthy volunteers aged 1-14 yr. Participants followed American Society of Anesthesiologists fasting guidelines prior to data collection. Gastric ultrasound (US) was performed in the right lateral decubitus (RLD) position to determine the antral cross-sectional area (CSA). Following baseline measurements, participants consumed 250 mL of a clear fluid. We then performed gastric US at four time intervals: 30, 60, 90, and 120 min. Data were collected following a predictive model for gastric volume estimation using the formula: volume (mL) = -7.8 + (3.5 × RLD CSA) + (0.127) × age (months). RESULTS: We recruited 33 healthy children aged 2-14 yr. The mean gastric volume per weight (mL·kg-1) at baseline was 0.51 mL·kg-1 (95% confidence interval [CI], 0.46 to 0.57). The mean gastric volume was 1.55 mL·kg-1 (95% CI, 1.36 to 1.75) at 30 min, 1.17 mL·kg-1 (95% CI, 1.01 to 1.33) at 60 min, 0.76 mL·kg-1 (95% CI, 0.67 to 0.85) at 90 min, and 0.58 mL·kg-1 (95% CI, 0.52 to 0.65) at 120 min. CONCLUSION: Our results show that total gastric fluid volume was < 1.5 mL·kg-1 after 60 min, suggesting that current fasting guidelines for children could be liberalized.

RéSUMé: OBJECTIF: Les directives de jeûne pour les enfants recommandent de restreindre les liquides clairs pendant une ou deux heures avant une intervention pour réduire l'aspiration pulmonaire. Des volumes gastriques < 1,5 mL·kg−1 ne semblent pas présenter un risque accru d'aspiration pulmonaire. Notre objectif était de quantifier le temps nécessaire pour atteindre un volume gastrique < 1,5 mL·kg−1 après ingestion de liquides clairs chez les enfants. MéTHODE: Nous avons mené une étude observationnelle prospective chez des volontaires en bonne santé âgé·es de 1 à 14 ans. Les participant·es ont suivi les directives de jeûne de l'American Society of Anesthesiologists avant la collecte de données. L'échographie gastrique a été réalisée en décubitus latéral droit (DLD) pour déterminer la section transversale antrale. Après les mesures initiales, les participant·es ont consommé 250 mL d'un liquide clair. Nous avons ensuite réalisé une échographie gastrique à quatre intervalles de temps : 30, 60, 90 et 120 minutes. Les données ont été recueillies selon un modèle prédictif pour l'estimation du volume gastrique à l'aide de la formule : volume (mL) = −7,8 + (3,5 × section transversale antrale en DLD) + (0,127) × âge (mois). RéSULTATS: Nous avons recruté 33 enfants en bonne santé âgé·es de 2 à 14 ans. Le volume gastrique moyen par poids (mL·kg−1) au début de l'intervention était de 0,51 mL·kg−1 (intervalle de confiance [IC] à 95 %, 0,46 à 0,57). Le volume gastrique moyen était de 1,55 mL·kg−1 (IC 95 %, 1,36 à 1,75) à 30 min, 1,17 mL·kg−1 (IC 95 %, 1,01 à 1,33) à 60 min, 0,76 mL·kg−1 (IC 95 %, 0,67 à 0,85) à 90 min, et 0,58 mL·kg−1 (IC 95 %, 0,52 à 0,65) à 120 min. CONCLUSION: Nos résultats montrent que le volume total de liquide gastrique était < 1,5 mL·kg−1 après 60 min, suggérant que les directives actuelles de jeûne pour les enfants pourraient être libéralisées.

Differences in preoperative gastric ultrasound findings in elderly compared to the mid-aged surgical patients: A retrospective observational study.

This study aimed to compare gastric ultrasound assessments between young and elderly patients, to determine whether the cross-section area (CSA) cutoff values for elderly and young patients should be different, and to suggest CSA cutoff values for elderly patients. This study evaluated the data of 120 patients who underwent elective surgery under general anesthesia between July 2019 and August 2020. Demographic and gastric ultrasound assessment data were retrieved. Patients were divided into the elderly group (n = 58, age: ≥65 years) and young group (n = 62, age: <65 years). The CSAs in the supine and right lateral decubitus positions (RLDP), semiquantitative 3-point Perlas grade (grades 0, 1, and 2), and gastric volume (GV) were determined. CSAs according to different Perlas grades were compared between the 2 groups. To compare normally and non-normally distributed continuous data, Student t test and the Mann-Whitney U test were used, respectively. Categorical data were compared using the chi-square test or Fisher exact test, as appropriate. The receiver operating characteristic (ROC) curves were built for the CSAs to predict pulmonary aspiration. The CSA cutoff values for predicting a high risk of pulmonary aspiration in both the groups were determined. Among patients with Perlas grade 0, the CSAsupine (P = .002) and CSARLDP (P = .002) were greater in the elderly group than in the young group. The specificity, positive predictive value, and accuracy of the CSA decreased when the CSA cutoff value for the young group was applied to the elderly group. The CSA cutoff values for the elderly group were: CSAsupine, 6.92 cm2 and CSARLDP, 10.65 cm2. The CSA of the empty stomach was greater in elderly patients than in young patients. We suggest that the following CSA cutoff values should be used for predicting pulmonary aspiration risk in elderly patients: CSAsupine, 6.92 cm2 and CSARLDP, 10.65 cm2.

Reinforcing the valuable role of gastric ultrasound for volume and content assessment: an observational study

Abstract Background Pulmonary aspiration is one of the most important complications in anesthesiology. Assessment of gastric content by ultrasound is a good method to quantify gastric volume and to determine the risk of intraoperative pulmonary aspiration. The aim of this study is to determine the accuracy of the gastric ultrasonography in the qualitative analysis of gastric content, mainly in the analysis of small amounts of liquid content. Methods Gastric ultrasound was performed to 36 patients before upper gastrointestinal endoscopy (UGI), making two longitudinal scans at the epigastric level, one in supine position and the other in right lateral decubitus position, measuring two diameters and the area of the gastric antrum and assessing the content characteristics determining whether it was an empty stomach or contained fluid or solid content. Subsequently, the ultrasound findings were compared with UGI findings. Results Gastric areas were analyzed by the trace and the lengths of the craniocaudal and anteroposterior axes concluding that there are no significant differences between the two methods. No statistically significant difference was found between UGI and US assessment technics. No statistically significant difference was found between the estimated volume by UGI and US. Conclusions Though our study has some limitations, qualitative analysis of gastric content using ultrasound followed by endoscopy enabled the conclusion that there are no differences in the qualitative assessment regarding these two techniques, supporting the important role of point-of-care gastric ultrasound (POCGUS) in the assessment of pulmonary aspiration risk by the anesthesiologist in the perioperative period.

Diagnostic performance of qualitative ultrasound assessment for the interpretation of point-of-care gastric ultrasound to detect high gastric fluid volume: A prospective randomized crossover study.

STUDY OBJECTIVE: This study aimed to assess whether elevating the head of the bed to 45° was associated with sensitivity >90% of the qualitative ultrasound assessment for the diagnosis of gastric fluid volume > 1.5 ml.kg-1. We also assessed the performance of qualitative assessment, composite ultrasound scale, and clinical algorithm, for the diagnosis of fluid volume > 1.5 ml.kg-1 according to whether the head of the bed was elevated to 45° or not. DESIGN: Prospective randomized observer-blind crossover trial. SETTING: Hospices Civils de Lyon, France. PATIENT: Healthy adult volunteers. INTERVENTIONS: Two separate study sessions in fasting volunteers: with and without head-of-bed elevation to 45°, in a randomized order. Each session consisted of three tests, each corresponding to a randomized and different volume of water (either 0, 50, 100, 150 or 200 ml); the same volumes were used in both sessions and in a randomized order. Gastric ultrasounds were performed three minutes after the ingestion of water by an investigator blinded to the volume ingested. MEASUREMENTS: Diagnostic performance of each approach for the diagnosis of gastric fluid volume > 1.5 ml.kg-1. MAIN RESULTS: Twenty volunteers were included, and 120 measurements were analyzed. The sensitivity of the qualitative assessment for the diagnosis of gastric fluid volume > 1.5 ml.kg-1 with and without head-of-bed elevation was 91% (95%CI: 75-98) and 75% (95%CI: 57-89), respectively. The clinical algorithm with head-of-bed elevation had significantly better sensitivity than the qualitative assessment with no head-of-bed elevation; there was no significant difference for other comparisons. CONCLUSIONS: The results suggest that qualitative examination of gastric antrum in the supine position with head-of-bed elevation to 45° can discriminate between low and high gastric fluid volume with high sensitivity, while neither the composite ultrasound scale nor the clinical algorithm improved the diagnostic performance of gastric ultrasound for the diagnosis of gastric fluid volume > 1.5 ml.kg-1.

Ultrasound assessment of gastric contents in children before general anaesthesia for acute appendicitis.

There is increasing evidence that a minority of adults with acute appendicitis have gastric contents, posing an increased risk of pulmonary aspiration. This study aimed to evaluate the proportion of children with acute appendicitis who have gastric contents considered to pose a higher risk of pulmonary aspiration. We analysed point-of-care gastric ultrasound data routinely collected in children before emergency appendicectomy in a specialist paediatric hospital over a 30-month period. Based on qualitative and quantitative antral assessment in the supine and right lateral decubitus positions, gastric contents were classified as 'higher-risk' (clear liquid with calculated gastric fluid volume > 0.8 ml.kg-1 , thick liquid or solid) or 'lower-risk' of pulmonary aspiration. The 115 children studied had a mean (SD) age of 11 (3) years; 37 (32%; 95%CI: 24-42%) presented with higher-risk gastric contents, including 15 (13%; 95%CI: 8-21%) with solid/thick liquid contents. Gastric contents could not be determined in 13 children as ultrasound examination was not feasible in the right lateral decubitus position. No cases of pulmonary aspiration occurred. This study shows that gastric ultrasound is feasible in children before emergency appendicectomy. This technique showed a range of gastric content measurements, which could contribute towards defining the risk of pulmonary aspiration.

Prevalence of risk stomach in laboring women allowed to unrestrictive oral intake: a comparative cross-sectional study.

BACKGROUND: Although restricting food intake during labor is recommended by guidelines, intrapartum starvation has not been popular in some regions. We conducted this comparative cross-sectional study to determine the prevalence of risk stomach in non-fasted laboring women compared with fasted non-laboring women using gastric ultrasound. METHODS: Ultrasound examination of the antrum was performed in 50 term fasted non-laboring women before elective cesarean delivery and 50 laboring women allowed to eat and drink during active labor. Examinations consisted of the qualitative (antral grades, 0-3) and quantitative evaluation (antral cross-sectional area and calculated gastric volume) in the supine and right lateral decubitus (RLD) position. A risk stomach was defined as an antral grade ≥ 2 or grade 1 with gastric volume ≥ 1.5 ml· kg- 1. RESULTS: No non-laboring women had grade ≥ 2, while 34 (68%) laboring women had grade ≥ 2. Nine (18%) non-laboring and 40 (80%) laboring women presented risk stomach (P < 0.001) (risk ratio: 4.4, 95% CI 2.4-8.2). Compared with non-laboring women, laboring women had larger antral area at "empty" stomach (grade 0) (437 mm2 vs.350 mm2 in supine, 571 mm2 vs.480 mm2 in RLD, P < 0.05) and cut-off values of antral area to discriminate a risk stomach (510 mm2 vs. 453 mm2 in supine, 670 mm2 vs. 605 mm2 in RLD). CONCLUSIONS: This study confirms a higher prevalence of risk stomach presents in laboring women under a liberal eating policy, gastric ultrasound is therefore useful for this risk population if general anesthesia is required unexpectedly.

Ultrasound assessment of the gastric content among diabetic and non-diabetic patients before elective surgery: a prospective multicenter study.

BACKGROUND: Although diabetic gastroparesis could be responsible for delayed gastric emptying, there is conflicting evidence about the volume of gastric content in diabetic patients after preoperative fasting. We hypothesized that diabetic patients had an increased gastric content before anesthesia induction despite the following of fasting recommendations. We used ultrasound assessment of gastric content to evaluate this risk. METHODS: This multicenter prospective single-blinded case-control study was conducted in three teaching University hospital in France. Our primary outcome was the comparison of increased gastric content between the two groups and was defined either by a Perlas grade 2 antrum or an antral cross-sectional area (CSA)>340 mm2. Each diabetic patient was paired with three non-diabetic control patients. Forty-two diabetic and 126 control patients were included in the study. RESULTS: Eighteen (42.9%) diabetic patients reached the primary outcome versus 28 (22.2%) in the control group (P=0.009). Diabetic patients presented less frequently with an empty stomach. Indeed, ten (23.8%) diabetic patients had a grade 0 antrum versus 71 (56.3%) in the control group (P<0.001). Twenty-four (70.6%) diabetic patients had an antral CSA<340 mm2 versus 98 (86%) in the control group (P=0.039). Overall, diabetic patients and increased gastric content were associated with an Odds Ratio, 2.63; 95% confidence interval, 1.25-5.52, P=0.009. CONCLUSIONS: Our study documents that gastric content is increased among diabetic patients compared to control patients despite following appropriate fasting guidelines.

Ultrasonographic assessment of preoperative gastric volume in patients with dyspepsia: a prospective observational study.

BACKGROUND: Patients undergoing gastroenteroscopy during sedation are prone to aspiration, and most patients with dyspepsia have delayed gastric emptying. This study aimed to investigate the feasibility of measuring the gastric antrum cross-sectional area (CSA) to supply a novel clinical diagnostic reference value in patients with dyspepsia. METHODS: Patients with dyspepsia undergoing elective gastroscopy were included. The Perlas qualitative 0-2 grading scale score was determined before the operation. The anteroposterior diameter (D1) and craniocaudal diameter (D2) between gastric antrum serosal surfaces were measured perpendicular to each other in the supine and right lateral decubitus (RLD) positions. CSA values in the supine position and RLD position were determined. Gastric contents were endoscopically suctioned with the volumes measured and noted as actual gastric volume. Multiple regression analysis was used to fit a mathematical model for estimating the gastric volume. Receiver operating characteristic (ROC) curves were constructed to determine the accuracy of RLD CSA to detect gastric volumes of > 0.8 ml/kg. RESULTS: A total of 117 patients were enrolled and divided into a functional dyspepsia (FD) group and an organic dyspepsia group according to gastroscopy findings. For a gastric volume of > 0.8 ml/kg, cut-off values for FD and organic dyspepsia were 6.7 cm2 and 10.0 cm2, respectively. Two new modified mathematical models were derived to predict an estimated gastric volume for FD and organic dyspepsia: volume = 3.93 × RLD CSA - 0.47 × age; and volume = 6.15 × RLD CSA - 0.61 × age. CONCLUSION: We used the cut-off value of the antral area for the fast diagnosis of gastric volumes in patients with dyspepsia, which may assist clinicians in identifying patients at risk of aspiration. TRIAL REGISTRATION: www.chictr.org.cn ( CHICTR-DDD-17010871 ); registered 15 March 2017.

Qualitative and quantitative gastric ultrasound assessment in highly skilled regional anesthesiologists.

BACKGROUND: Pulmonary aspiration is a major complication in anesthesia, and various studies have shown that gastric sonography can reliably provide valuable information relative to both the qualitative and quantitative aspects of gastric content. This study aimed to determine the accuracy of ultrasound assessment of gastric content compared between two novice anesthesiologist gastric sonographers. METHODS: This prospective cohort study of two anesthesiologists learning to perform qualitative and quantitative ultrasound assessment of gastric content on healthy volunteers was conducted at Siriraj Hospital (Bangkok, Thailand). This trial was registered with ClinicalTrials.gov (reg. no. NCT04760106). RESULTS: Of the 50 enrolled participants, three were excluded due to study protocol violation. Each anesthesiologist performed a qualitative assessment on 47 participants for an overall total of 94 scans. There were 15 males and 32 females (age 42 ± 11.7 years, weight 61.2 ± 13.1 kg, height 160.7 ± 7.3 cm, and BMI 23.6 ± 4.3 kg/m2). The overall success rate for all gastric content categories was approximately 96%. From antral cross-sectional area measurement, as the ingested volume increased, there was a tendency toward increased deviation from the actual ingested volume. Interrater agreement between anesthesiologists was analyzed using intraclass correlation coefficients (ICCs). A larger fluid volume was found to be associated with a lower level of agreement between the two anesthesiologists. The ICCs were 0.706 (95% CI: -0.125 to 0.931), 0.669 (95% CI: -0.254 to 0.920), 0.362 (95% CI: -0.498 to 0.807) for the 100 ml, 200 ml, and 300 ml fluid volumes, respectively. The mean duration to perform an ultrasound examination for each gastric content category and for the entire examination did not differ significantly between anesthesiologists (p > 0.05). CONCLUSION: Our results indicate that qualitative ultrasound assessment of gastric content is highly accurate and can be easily learned. In contrast, quantification of gastric volume by novice gastric sonographers is more complex and requires more training. TRIAL REGISTRATION: ClinicalTrials.gov no. NCT04760106 Date registered on Feb 11, 2021. Prospectively registered.

Point-of-Care Ultrasound to Assess Gastric Content in Pediatric Emergency Department Procedural Sedation Patients.

OBJECTIVES: There is debate regarding the timing of procedural sedation and analgesia (PSA) in relation to fasting status. Point-of-care ultrasound (POCUS) provides the ability to measure gastric content and is being used as a surrogate for aspiration risk in anesthesia. We sought to evaluate the gastric content of pediatric emergency department (PED) patients undergoing PSA using POCUS. METHODS: We performed a prospective observational study using a convenience sample of pediatric patients undergoing PSA between July 1, 2018, and June 30, 2019. Following a brief history, gastric content was measured using POCUS in both supine and right lateral decubitus positions at 2-hour intervals until the time of PSA. Qualitative content and calculated volume were classified based on the Perlas Model of anesthesia "Risk" assessment. RESULTS: Ninety-three patients were enrolled with 61.3% male and mean age of 6.5 years. Gastric content was determined in 92 patients. There were 79.3% that had "high risk" content at the time of PSA, with a median fasting time of 6.25 hours and no serious adverse events. Fasting duration had a weak to moderate ability to predict "risk" category (area under the curve = 0.73), with no patient (n = 17) who underwent multiple evaluations awaiting PSA progressing from "high" to "low risk." CONCLUSIONS: The majority of PED patients undergoing PSA at our institution had "high risk" gastric content with no clinically significant change occurring during serial evaluations. This calls into question the utility of delaying PSA based upon fasting status and lends support to a more comprehensive risk-benefit approach when planning pediatric PSA.

Evaluation of gastric contents using ultrasound in full-term pregnant women fasted for 8 h: a prospective observational study.

BACKGROUND: We aimed to evaluate the gastric volume and contents after an 8-h fasting period in full-term, non-laboring, pregnant women following a standardized meal. METHODS: In this prospective observational study, we included full-term pregnant women scheduled for elective cesarean delivery. The participants were instructed to fast after a standardized meal (apple juice, bread, and cheese). Participants were scanned in the semi-recumbent and right-lateral positions 8 h after the standardized meal. The primary outcome was the proportion of patients with gastric volume > 1.5 mL kg-1 calculated by two equations. Secondary outcomes included the antral cross-sectional area and gastric volume. Data are expressed as frequency (%, 95% confidence interval [CI]), mean ± standard deviation (95% CI of the mean), or median (quartiles) as appropriate. RESULTS: Forty-one women were available for the final analysis. For the primary outcome, one participant (2.4%, 95% CI of 0.06 to 12.8%) had gastric volume > 1.5 mL kg-1, and none had solids in the antrum. For the secondary outcomes, the mean (95% CI of the mean) of the antral cross-sectional area was 2.11 ± 0.72 (1.88 to 2.34) cm2 and 4.08 ± 1.80 (3.51 to 4.65) cm2 during the semi-recumbent and right-lateral position, respectively. The median (quartiles) gastric volume was 0.53 (0.32, 0.66) mL kg-1 and 0.33 (0.13, 0.52) mL kg-1 as estimated by Perlas et al. and Roukhomovsky et al. equations, respectively. CONCLUSION: After 8-h fasting following a standardized meal, full-term pregnant non-laboring women are less likely to have a high residual gastric volume.

Reinforcing the valuable role of gastric ultrasound for volume and content assessment: an observational study.

BACKGROUND: Pulmonary aspiration is one of the most important complications in anesthesiology. Assessment of gastric content by ultrasound is a good method to quantify gastric volume and to determine the risk of intraoperative pulmonary aspiration. The aim of this study is to determine the accuracy of the gastric ultrasonography in the qualitative analysis of gastric content, mainly in the analysis of small amounts of liquid content. METHODS: Gastric ultrasound was performed to 36 patients before upper gastrointestinal endoscopy (UGI), making two longitudinal scans at the epigastric level, one in supine position and the other in right lateral decubitus position, measuring two diameters and the area of the gastric antrum and assessing the content characteristics determining whether it was an empty stomach or contained fluid or solid content. Subsequently, the ultrasound findings were compared with UGI findings. RESULTS: Gastric areas were analyzed by the trace and the lengths of the craniocaudal and anteroposterior axes concluding that there are no significant differences between the two methods. No statistically significant difference was found between UGI and US assessment technics. No statistically significant difference was found between the estimated volume by UGI and US. CONCLUSIONS: Though our study has some limitations, qualitative analysis of gastric content using ultrasound followed by endoscopy enabled the conclusion that there are no differences in the qualitative assessment regarding these two techniques, supporting the important role of point-of-care gastric ultrasound (POCGUS) in the assessment of pulmonary aspiration risk by the anesthesiologist in the perioperative period.

Size and Number of Food Boluses in the Stomach after Eating Different Meals: Magnetic Resonance Imaging Insights in Healthy Humans.

Oral processing of food results in the formation of food boluses, which are then swallowed and reach the stomach for further digestion. The number, size and surface properties of the boluses will affect their processing and emptying from the stomach. Knowledge of these parameters, however, is incomplete due to limitations of the techniques used. In this work, non-invasive magnetic resonance imaging (MRI) was used for the first time to measure boluses in the stomach a few minutes after swallowing. Three groups of nine healthy participants were fed three different meals: chicken and roasted vegetables (Meal 1), bread and jam (Meal 2) and cheese and yogurt (Meal 3), and then, their stomach content was imaged. The median number of boluses within the stomach was 282, 106 and 9 for Meal 1, Meal 2 and Meal 3 (p < 0.0001) with an average volume of 0.47 mL, 2.4 mL and 13.6 mL, respectively (p < 0.0001). The cohesiveness as well as the meal composition seem to play a key role in the resulting boluses. These new in vivo data from undisturbed organ imaging can improve knowledge of the digestion process, which will, in turn, inform in vitro and in silico modelling of digestion, thus improving their in vitro/in vivo relevance.

Prediction of postoperative nausea and vomiting by point-of-care gastric ultrasound: can we improve complications and length of stay in emergency surgery? A cohort study.

BACKGROUND: Postoperative nausea and vomiting and postoperative ileus are common after major digestive surgery and represent one of the significant problems in Acute Care Surgery. The delivery model of emergency surgery needs to be improved in order to foster a patient-centered care. The multimodal approach suggested by Enhanced Recovery After Surgery (ERAS®) Guidelines is gaining widespread acceptance but is difficult to apply to emergency surgery. Ultrasound examination of the gastric antrum allows a reliable assessment of gastric contents and volume and might help contribute to improve perioperative care in the emergency setting. METHODS: Gastric ultrasound examinations were performed preoperatively and postoperatively on forty-one patients undergoing emergency abdominal surgery. Gastric cross-sectional area (CSA) was measured, in order to estimate the gastric volume. The data obtained were used to evaluate a possible relationship between delayed gastric emptying and postoperative adverse event. RESULTS: Gastric antrum detection rate varied from 31.8% in open up to 78.9% in laparoscopic surgeries (p = 0.003). Six patients experienced adverse outcomes, had an antiemetic therapy administered and/or a nasogastric tube inserted. Mean CSA was significantly higher in this group (12.95 cm2 vs 6.12 cm2; p = 0.040). CONCLUSIONS: Sensitivity of gastric ultrasound varies depending on surgical technique. A dilated gastric antrum is significantly related to postoperative adverse outcomes and a careful ultrasound follow-up might help tailor postoperative nutrition and antiemetic therapy. In patients who experienced adverse events, antral CSA showed an average increase of more than 50% over a period of 72 h after surgery. A relative measure could be used to predict the risk of postoperative ileus. Overall, gastric ultrasound seems to be a promising diagnostic tool and a useful way to integrate ERAS® protocol in emergency abdominal surgery.

Prediction of gastric fluid volume by ultrasonography in infants undergoing general anaesthesia.

BACKGROUND: Point-of-care ultrasonography can estimate gastric contents and volume to assess the risk of pulmonary aspiration; however, its use in infants has not been well validated. We aimed to develop a predictive model for estimating gastric fluid volume using ultrasonography in infants. METHODS: This prospective observational study enrolled 200 infants (≤12 months) undergoing general anaesthesia. After anaesthetic induction, while preserving spontaneous respiration, we measured gastric antral cross-sectional area using ultrasonography in both the supine and right lateral decubitus positions. We then suctioned the gastric content and measured its volume. The primary outcome was development of a gastric fluid volume prediction model with multiple regression analysis. Agreement between the predicted volume and the suctioned volume was evaluated using a Bland-Altman plot. RESULTS: Overall, 192 infants were included in the final analysis. Pearson correlation analysis showed that the gastric antral cross-sectional area in the supine (P<0.001; correlation coefficient: 0.667) and right lateral decubitus (P<0.001; correlation coefficient: 0.845) positions and qualitative antral grade (P<0.001; correlation coefficient: 0.581) correlated with suctioned volume. We developed a predictive model: predicted volume (ml)=-3.7+6.5 × (right lateral decubitus cross-sectional area [cm2])-3.9 (supine cross-sectional area [cm2])+1.7 × grade (P<0.01). When comparing the predicted volume and suctioned volume, the mean bias was 0.01 ml kg-1 and the limit of agreement was -0.58 to 0.62 ml kg-1. CONCLUSIONS: Gastric fluid volume can be estimated using a predictive model based on ultrasonography data in infants. CLINICAL TRIAL REGISTRATION: NCT03155776.

Gastric content and perioperative pulmonary aspiration in patients with diabetes mellitus: a scoping review.

BACKGROUND: Gastric emptying may be delayed in patients with diabetes mellitus (DM). However, the incidence of full stomach in fasting patients with DM and their risk of pulmonary aspiration under anaesthesia is not well understood. METHODS: A scoping review was undertaken to map the literature on aspiration risk in DM. A search was conducted in seven bibliographic databases, including MEDLINE and Embase, for original articles that studied aspiration risk, gastric emptying, or gastric content and volume. Selection and characterisation were performed by two independent reviewers using a predefined protocol registered externally. RESULTS: The search identified 5063 unique records, and 16 studies (totalling 775 patients with DM) were selected: nine studied gastric emptying and seven studied gastric content or volume. There were no studies reporting the incidence of aspiration in subjects with DM. All nine studies reported delayed emptying in patients with DM compared with healthy controls. Amongst the seven studies that compared gastric residual content/volume (GRV) in the perioperative period, five reported clinically negligible GRV in both patients with DM and controls, whereas two observed a higher incidence of 'full' stomach in patients with DM. CONCLUSIONS: The evidence concerning the aspiration risk for surgical patients with DM is based on a limited number of studies, mostly unblinded, reporting physiological data on gastric emptying and gastric volume as surrogate markers of aspiration risk. Data on fasting gastric content and volume in patients with DM are limited and contradictory; hence, the true risk of aspiration in fasting patients with DM is unknown.

Does ultrasonographic assessment of gastric antrum correlate with gastric residual volume in critically ill patients? A prospective observational study.

This study aimed to evaluate the relationship between ultrasonographic gastric antral measurements and aspirated gastric residual volume (GRV) in mechanically ventilated critically ill patients receiving enteral nutrition (EN). This prospective observational study included 56 enterally-fed critically ill patients in one-year period. All imaging procedures were done at 30-degree head-of-bed elevation and supine position on epigastric region of abdomen with 2.5-6 MHz convex-array probe just before routine GRV aspiration. The antral cross-sectional area (CSA) was calculated by measuring the anteroposterior (dAP) and craniocaudal diameters (dCC) of the gastric antrum. Total 283 ultrasonographic gastric antrum imaging procedures were done. In only eight (2.82%) attempts, the antrum could not be visualized due to inhibition from intra-gastric air or gas in the surrounding intestinal lumen. The calculated mean antral CSA was 568.15 ± 348.37 mm2 (103.43-2,846.30). The antral CSA correlated significantly with aspirated GRV, and the antral CSA increased linearly with increasing aspirated GRV (R2 = 0.73, p < 0.0001). In Receiver operating characteristic (ROC) analysis of antral CSA ≥ 920 mm2 (mean + 1*SD) for estimating aspirated GRV, the area under the curve (AUC) was 0.848 (95% CI, 0.76 ~ 0.93) (p < 0.0001), and ROC analysis of antral CSA to discriminate aspirated GRV ≥ 250 mL showed a significant relation (AUC = 0.969, 95% CI 0.94 ~ 0.99, p < 0.0001). Ultrasonographic measurement of gastric antral CSA is an easy and reliable bedside procedure to estimate GRV in critically ill patients receiving EN in 30-degree head-of-bed elevation and supine position. Trial registration number: NCT04413474, date of registration: June 17, 2020, retrospectively registered.