BACKGROUND: Practice on fasting prior to extubation in critically ill patients is variable. Efficacy of fasting in reducing gastric volume has not been well established. The primary objective of this study was to assess the effect of 4 h of fasting on prevalence of empty stomach using gastric ultrasonography in critically ill subjects who are fasted for extubation. The secondary objectives were to evaluate the change in gastric volumes during 4 h of fasting and to determine factors associated with empty stomach after fasting.
METHODS: This was a single-center, prospective, observational study on adult ICU subjects who were enterally fed for at least 6 h continuously and mechanically ventilated. Gastric ultrasound was performed immediately prior to commencement of fasting, after 4 h of fasting, and after nasogastric (NG) aspiration after 4 h of fasting. An empty stomach was defined as a gastric volume ≤ 1.5 mL/kg.
RESULTS: Forty subjects were recruited, and 38 (95%) had images suitable for analysis. The prevalence of empty stomach increased after 4 h of fasting (25 [65.8%] vs 31 [81.6%], P = .041) and after 4 h of fasting with NG aspiration (25 [65.8%] vs 34 [89.5%], P = .008). There was a significant difference in median (interquartile range) gastric volume per body weight between before fasting and 4 h after fasting (1.0 [0.5-1.8] mL/kg vs 0.4 [0.2-1.0] mL/kg, P < .001). No patient factors were associated with higher prevalence of empty stomach after 4 h of fasting.
CONCLUSIONS: Most mechanically ventilated subjects had empty stomachs prior to fasting for extubation. Fasting for 4 h further increased the prevalence of empty stomach at extubation to > 80%.

We aimed to assess the accuracy of ultrasonographic measurement of the antral cross-sectional area (CSA) in the preprocedural evaluation of gastric contents and volume in fasted patients > 60 yr of age scheduled for gastroscopy under sedation.
We included n = 81 patients > 60 yr of age and n = 79 younger controls scheduled to undergo elective gastroscopy in a prospective cohort study. A gastric ultrasound examination was performed to measure the antral CSA in both semisitting and right lateral decubitus (RLD) positions. Afterward, patients were graded using the Perlas qualitative grading scale. The actual gastric volume was endoscopically suctioned. Full stomach was defined as gastric volume > 1.5 mL·kg-1 and/or the presence of solid particles. We constructed receiver operating characteristic curves to determine the accuracy of ultrasonographic measurement of RLD CSA to detect a gastric volume > 1.5 mL·kg-1 and calculated the diagnostic test attributes of RLD CSA for the identification of a gastric volume > 1.5 mL·kg-1 RESULTS: The incidence of full stomach was 8/81 (9.8%) in patients > 60 yr of age and 1/79 (1.2%) in young patients (risk difference, 8.6%; 95% CI, 1.3 to 15.8; P = 0.03). The cut-off value of RLD CSA was 10.4 cm2 for the detection of gastric volume > 1.5 mL·kg-1 in patients > 60 yr of age, with a sensitivity of 75%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 98.6%.
Patients > 60 yr of age scheduled for gastroscopy under sedation had a higher incidence of a full stomach detected with ultrasound compared with a younger cohort, which is potentially associated with a higher aspiration risk. We calculated a cut-off value of RLD CSA for detecting gastric volume in patients > 60 yr of age of approximately 10 cm2, which may help to quickly assess patients at risk of aspiration.
www.chictr.org.cn (ChiCTR2100048994); registered 19 July 2021.
RéSUMé: CONTEXTE: Notre objectif était d’évaluer la précision de la mesure échographique de la section transversale antrale (CSA) dans l’évaluation préprocédurale du contenu et du volume gastriques chez les patient·es à jeun > 60 ans devant bénéficier d’une gastroscopie sous sédation. MéTHODE: Nous avons inclus n = 81 patient·es > 60 ans et n = 79 patient·es témoins plus jeunes devant bénéficier d’une gastroscopie non urgente dans une étude de cohorte prospective. Une échographie gastrique a été réalisée pour mesurer la CSA antrale en position semi-assise et en décubitus latéral droit (DLD). Par la suite, la patientèle a été classée à l’aide de l’échelle de classement qualitatif de Perlas. Le volume gastrique réel était aspiré par endoscopie. Un estomac plein a été défini comme un volume gastrique > 1,5 mL·kg–1 et/ou la présence de particules solides. Nous avons construit des courbes de la fonction d’efficacité du récepteur (courbes ROC) afin de déterminer la précision de la mesure échographique de la CSA en DLD pour détecter un volume gastrique > 1,5 mL·kg–1 et calculé les attributs du test diagnostique de la CSA en DLD pour identifier un volume gastrique > 1,5 mL·kg–1. RéSULTATS: L’incidence d’estomac plein était de 8/81 (9,8 %) chez les patient·es > 60 ans et 1/79 (1,2 %) chez les patient·es jeunes (différence de risque, 8,6 %; IC 95 %, 1,3 à 15,8; P = 0,03). La valeur seuil de la CSA en DLD était de 10,4 cm2 pour la détection d’un volume gastrique > 1,5 mL·kg–1 chez la patientèle > 60 ans, avec une sensibilité de 75 %, une spécificité de 100 %, une valeur prédictive positive de 100 % et une valeur prédictive négative de 98,6 %. CONCLUSION: La patientèle > 60 ans devant bénéficier d’une gastroscopie sous sédation avait une incidence plus élevée d’estomac plein détecté par échographie par rapport à une cohorte plus jeune, ce qui est potentiellement associé à un risque d’aspiration plus élevé. Nous avons calculé une valeur seuil de la CSA en DLD pour détecter le volume gastrique chez les patient·es > 60 ans d’environ 10 cm2, ce qui peut aider à évaluer rapidement les personnes à risque d’aspiration. ENREGISTREMENT DE L’éTUDE: www.chictr.org.cn (ChiCTR2100048994); enregistrée le 19 juillet 2021.

Objective: The present study aimed to use bedside ultrasound to evaluate the effects of metoclopramide on gastric motility in patients being treated for trauma in the emergency department. Methods: Fifty patients underwent an ultrasound immediately after attending the emergency department of Zhang Zhou Hospital due to trauma. The patients were randomly divided into two groups: a metoclopramide group (group M, n = 25) and a normal saline group (group S, n = 25). The cross-sectional area (CSA) of the gastric antrum was measured at 0, 30, 60, 90, and 120 min (T = time). The gastric emptying rate (GER, GER=-AareaTn/AareaTn-30-1×100), GER/min (GER divided by the corresponding interval time), gastric content properties, Perlas grade at different time points, T120 gastric volume (GV), and GV per unit of body weight (GV/W) were evaluated. The risk of vomiting, reflux/aspiration, and type of anesthetic treatment were also evaluated. Results: The differences between the two groups in the CSA of the gastric antrum at each time point were statistically significant (p < 0.001). The CSAs of the gastric antrum in group M were lower than those in group S, and the greatest difference between the two groups occurred at T30 (p < 0.001). The differences between the two groups in GER and GER/min were also statistically significant (p < 0.001); those differences in group M were higher than those in group S, and the greatest differences between the two groups occurred at T30 (p < 0.001). There were no obvious change trends in the properties of the gastric contents and the Perlas grades in either group, and the differences between the two groups were not statistically significant (p = 0.97). The differences between the two groups in the GV and GV/W at T120 were statistically significant (p < 0.001), as was the risk of reflux and aspiration at T120 (p < 0.001). Conclusion: When metoclopramide was used in satiated emergency trauma patients, it accelerated gastric emptying within 30 min and reduced the risk of accidental reflux. However, a normal gastric emptying level was not achieved, which can be attributed to the delaying effect of trauma on gastric emptying.

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.
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.
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).
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.

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.

This prospective study was designed to evaluate gastric volume and content in patients with renal failure and healthy controls after an overnight fast, immediately after a light meal and at 6 h after the meal. Thirty subjects in each group were recruited. At each scanning session, gastric antral cross-sectional area was measured in the supine recumbent and right lateral decubitus positions, and a qualitative assessment of gastric contents was made using the Perlas three-point grading system. Six hours after the meal, the mean (SD) antral cross-sectional area in the supine position was 471 (195) mm2 in patients with renal failure and 319 (106) mm2 in healthy controls (p = 0.028), whereas in the right lateral position it was 756 (320) and 521 (180) mm2 , respectively (p = 0.21). In terms of the qualitative assessments of gastric contents, all subjects had an empty stomach after an overnight fast. Five patients with renal failure and no controls had Perlas grade 2 images, indicating significant gastric contents, 6 h after a meal (p = 0.026). This study supports the use of bedside gastric ultrasound as a point-of-care test for patients with known risk factors for delayed gastric emptying.