An observational study in Fasting, Delayed Gastric Emptying and Aspiration Pneumonia, sponsored by Boston Children's Hospital. Recruiting at 1 site in United States. Open to participants aged 2 Years to 18 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-04-02.
Sponsored by Boston Children's Hospital · Observational
The goal of this pilot prospective cohort study is to examine the reproducibility of gastric volume and emptying as measured by gastric ultrasound and its correlation to a gold-standard test for gastric emptying in the perioperative period in pediatric patients. The main questions it aims to answer are:
The study will include two cohorts. Cohort assignment will be based on age and anesthesia induction plan. Subjects >7yrs of age and expected to get an IV induction will be assigned to Cohort #1. Subjects \<7yrs of age and not expected to get an IV induction will be assigned to Cohort #2.
392 studies on the registry are indexed under Fasting; 63 are open to participants now.
This study's planned enrollment of 60 is below the median of 100 across 74 observational studies indexed under Fasting.
Browse Fasting studies →Boston Children's Hospital is the lead sponsor of 608 studies on the registry; 147 are open to participants now.
Of its 32 completed or terminated interventional studies of FDA-regulated products, 19 (59%) have results posted.
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This study is enrolling healthy pediatric subjects ages 2 through 17 years of age who are undergoing surgery with anesthesia at Boston Children's Hospital.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cohort 1 will include subjects who have a peripheral intravenous line placed in the pre-op area per routine care. This cohort is on average age 7 years and older. Procedures for cohort 1 will include: (a) gastric US measurement of the antral CSA and gastric volume using the Perlas US qualitative grading assessment by an expert and a novice operator to determine the inter-rater class reliability and repeat measurements by each operator to assess the intra-rater reliability (Aim 1), and (b) serial abdominal ultrasounds for gastric assessment and the acetaminophen absorption test to determine the correlation between gastric US and a gold-standard for gastric emptying (Aim 2). The acetaminophen absorption test requires administering a single weight-based enteral dose of acetaminophen with 6 oz of water and drawing of blood samples through a peripheral intravenous line.
Diagnostic Test: Gastric Ultrasound Baseline Scans · Diagnostic Test: Acetaminophen Absorption Test (AAT) · Diagnostic Test: Gastric Ultrasound Serial Scans
Cohort 2 will include subjects for whom a peripheral intravenous line placement is not part of routine pre-operative care. Average age for cohort 2 is age less than 7 years old. Procedures for Cohort 2 will include a gastric US measurement of the antral CSA and gastric volume using Perlas US qualitative grading assessment by an expert and a novice operator to determine the inter-rater class reliability and repeat measurements by each operator for the intra-rater reliability (Aim 1). This cohort is included to examine the reliability of measurements across age groups.
Diagnostic Test: Gastric Ultrasound Baseline Scans
The patient's abdomen will be scanned using the ultrasound device by an expert scanner and novice scanner for baseline assessment of the antral CSA and gastric volume using Perlas US qualitative grading assessment.
Prior to starting the AAT, a baseline plasma acetaminophen level (250 microliters) will be obtained from the intravenous catheter. The subject will then be given 12.5 mg/kg or max 650mg of single batch 32mg/mL acetaminophen followed by 6oz of water PO. Up to 3 additional small volume blood samples will be drawn for acetaminophen levels. These additional blood samples (250 microliters each) will be obtained to measure acetaminophen plasma levels at the following goal intervals after acetaminophen administration.T1:10-20 mins, T2:35-45 mins, T3: 60mins. At the time of each lab draw gastric ultrasound will be assessed by the expert scanner to correlate gastric ultrasound with the acetaminophen absorption test as a gold-standard of gastric emptying.
Cohort 1 will have multiple scans as part of assessing gastric emptying. These sequential scans after the baseline assessment will be done in line with the Acetaminophen Absorption Test timeline (T1:10-20 mins, T2:35-45 mins, T3: 60mins) and will be performed by an expert scanner only.
Inter-rater reliability
Measured using the following quantitative and qualitative ultrasound assessments between a novice and an expert gastric ultrasound operator: * Qualitative using the previously published Perlas' US qualitative grading assessment * Grade 0- no contents visualized in supine and lateral position * Grade 1- contents visualized in the lateral decubitus position (RLD) only * Grade 2- contents visualized in the supine and RLD. * Quantitative assessment using the cross-sectional area as published by Spencer AO et al. * Measurement of the CSA: longitudinal diameter (D1), and the antero-posterior diameter (D2) in both supine and RLD. Then these will be used to calculate the cross-sectional area (CSA) = (π\*D1\*D2)/4. * Quantitative assessment using the cross-sectional area as published by Spencer AO et al. * Measurement of the CSA: longitudinal diameter (D1), and the antero-posterior diameter (D2) in both supine and RLD. Then these will be used to calculate the cross-sectional area (CSA)
Time frame: 1 year
Intra-rater reliability
Measured using the following quantitative and qualitative ultrasound assessments between a novice and an expert gastric ultrasound operator: * Qualitative using the previously published Perlas' US qualitative grading assessment * Grade 0- no contents visualized in supine and lateral position * Grade 1- contents visualized in the lateral decubitus position (RLD) only * Grade 2- contents visualized in the supine and RLD. * Quantitative assessment using the cross-sectional area as published by Spencer AO et al. * Measurement of the CSA: longitudinal diameter (D1), and the antero-posterior diameter (D2) in both supine and RLD. Then these will be used to calculate the cross-sectional area (CSA) = (π\*D1\*D2)/4.
Time frame: 1 year
Gastric Emptying
Outcome will be gastric emptying assessed by the change in antral CSA (measured in cm2) over time after acetaminophen administration, and this will be correlated to gastric emptying over the same period of time by the acetaminophen absorption test PK parameter, AUC60 mcg\*min/mL. As such, each patient will act as their own control. Correlation analysis will be applied to examine the performance of CSA measurements overtime using gastric ultrasound to determine gastric emptying compared to the acetaminophen absorption test as the gold standard.
Time frame: 1 year
Post-anesthetic outcomes
Fasting times have been correlated to post-anesthetic outcomes such as post-operative nausea/ vomiting, and discomfort, and it is known that some patients fast longer than required by their clinical team, which can result in adverse effects. Reported fasting times for all patients and confirmatory assessment by gastric US will be examined along with data pulled from the medical record about post-operative nausea/ vomiting, post-operative discomfort, satisfaction, and whether the patient met their expected post-operative trajectory or not (e.g. unplanned admission).
Time frame: 1 year
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