Surgical patients are asked to adhere to preoperative fasting guidelines to minimize gastric contents. Large fluid volumes or solid content can still be present as shown with gastric ultrasound. It has been suggested that additional rating of patients\' satiety, measured as the feeling of hunger and thirst, could help clinicians to better judge emptying of the stomach.
We performed a prospective observational study in fasted elective surgical patients. The primary objective was to investigate the correlation between hunger measured on a 0-10 numeric rating scale and total gastric fluid volume measured with gastric ultrasonography. Secondary objectives included the correlation between 1) thirst and total gastric fluid volume and 2) hunger, thirst, and the Perlas grading scale score.
We included 515 patients. The exam was inconclusive in 14 individuals (2.7%). The Spearman correlation coefficient between gastric fluid volumes and hunger was 0.11 (95% confidence interval [CI], 0.02 to 0.20) (P = 0.01). The correlation between gastric fluid volumes and thirst was 0.11 (95% CI, 0.02 to 0.20) (P = 0.02). Between antral grades and numeric rating scale, the correlation coefficient was 0.00 (95% CI, -0.09 to 0.09) (P = 1.00) for thirst and 0.00 (95% CI, -0.08 to 0.09) (P = 0.94) for hunger. Ten patients (2.0%) had solid content, 24 presented a grade 2 antrum (4.8%).
This study suggests that the correlation between total gastric fluid volume and satiety sensation is very weak. Satiety did not reliably predict total gastric fluid volume.
ClinicalTrials.gov (NCT04884373); registered 13 May 2021.
RéSUMé: OBJECTIF: On demande aux patient·es de chirurgie de respecter les directives de jeûne préopératoire afin de minimiser leur contenu gastrique. Comme le montre l’échographie gastrique, de grands volumes de liquide ou des solides peuvent encore être présents. Il a été suggéré qu’une évaluation supplémentaire de la satiété des patient·es, mesurée par la sensation de faim et de soif, pourrait aider les clinicien·nes à mieux estimer la vidange de l’estomac. MéTHODE: Nous avons réalisé une étude observationnelle prospective chez des patient·es de chirurgie non urgente à jeun. L’objectif principal était d’étudier la corrélation entre la faim mesurée sur une échelle d’évaluation numérique de 0 à 10 et le volume total de liquide gastrique mesuré par échographie gastrique. Les objectifs secondaires comprenaient la corrélation entre 1) la soif et le volume total de liquide gastrique et 2) la faim, la soif et le score de l’échelle de classement Perlas. RéSULTATS: Nous avons inclus 515 personnes. L’examen était non concluant chez 14 individus (2,7 %). Le coefficient de corrélation de Spearman entre les volumes de liquide gastrique et la faim était de 0,11 (intervalle de confiance [IC] à 95 %, 0,02 à 0,20) (P = 0,01). La corrélation entre les volumes de liquide gastrique et la soif était de 0,11 (IC 95 %, 0,02 à 0,20) (P = 0,02). Entre les grades antraux et l’échelle d’évaluation numérique, le coefficient de corrélation était de 0,00 (IC 95 %, -0,09 à 0,09) (P = 1,00) pour la soif et de 0,00 (IC 95 %, -0,08 à 0,09) (P = 0,94) pour la faim. Un contenu solide a été observé chez dix personnes (2,0 %), et 24 présentaient un antre de grade 2 (4,8 %). CONCLUSION: Cette étude suggère que la corrélation entre le volume total de liquide gastrique et la sensation de satiété est très faible. La satiété n’a pas permis de prédire de manière fiable le volume total de liquide gastrique. ENREGISTREMENT DE L’éTUDE: clinicaltrials.gov (NCT04884373); enregistrée le 13 mai 2021.

In urgent situations, preoperative full stomach assessment mostly relies on clinical judgment. Our primary objective was to assess the diagnostic performance of clinical judgment for the preoperative assessment of full stomach in urgent patients compared to gastric point-of-care ultrasound (PoCUS). Our secondary objective was to identify risk factors associated with PoCUS full stomach in urgent patients.
We led a prospective observational study at our Hospital, between January and July 2016. Adult patients admitted for urgent surgery were eligible. Patients with altered gastric sonoanatomy, interventions reducing stomach content, impossible lateral decubitus were excluded. Clinical judgment and risk factors of full stomach were collected before gastric PoCUS measurements. Ultrasonographic full stomach was defined by solid contents or liquid volume ≥ 1.5 ml kg-1. Diagnostic performance was assessed through sensitivity, specificity, accuracy, positive and negative predictive value.
The prevalence of clinical and PoCUS full stomach in 196 included patients was 29% and 27%, respectively. Positive and negative predictive values were 42% (95% CI: 32.3-52.6%) and 79% (95% CI: 74.9-83.4%), respectively. Patients with PoCUS full stomach were clinically misdiagnosed in 55% of cases. PoCUS full stomach was associated with abdominal or gynaecological-obstetrical surgery (OR 3.6, 95% CI: 1.5-8.8, P < 0.01) but not with fasting durations. Positive solid intake after illness onset with respect to 6-h solid fasting rule was associated with PoCUS low-risk gastric content (OR 0.4, 95% CI: 0.2-0.9, P = 0.03).
Clinical judgment showed poor-to-moderate performance in urgent surgical patients for the diagnosis of full stomach. Gastric PoCUS should be used to assess risk of full stomach in this population.

Ultrasound examination of the gastric antrum is a non-invasive tool that allows reliable estimation of gastric contents. We performed this prospective cohort study in non-elective paediatric surgery to assess whether gastric ultrasound may help to determine the best anaesthetic induction technique, whether rapid sequence or routine. The primary outcome was the reduction of inappropriate induction technique. A pre-operative clinical assessment was performed by the attending anaesthetist who made a provisional plan for induction. Gastric ultrasound was performed in the semirecumbent and right lateral decubitus positions for a qualitative assessment of gastric contents, using a 0-2 grading scale. A final induction plan was made based on this assessment. Immediately after tracheal intubation, gastric contents were suctioned through a multi-orifice nasogastric tube; these were defined as above risk threshold for regurgitation and aspiration if there was clear fluid > 0.8 ml.kg-1 , and/or the presence of thick fluid and/or solid particles. Gastric ultrasound was feasible in 130 out of 143 (90%) of children, and led to a change in the planned induction technique in 67 patients: 30 from routine to rapid sequence, and 37 from rapid sequence to routine. An appropriate induction technique was therefore performed in 85% of children, vs. 49% planned after pre-operative clinical assessment alone (p < 0.00001). Our results suggest that gastric ultrasound is a useful guide to the general anaesthetic induction technique with respect to the risk of pulmonary aspiration, in comparison with pre-operative clinical assessment alone.