Gastric Assessment of Pediatric Patients Undergoing Surgery

March 27, 2026 updated by: Walid Alrayashi, Boston Children's Hospital

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:

  • What is the reliability (inter-rater variability between expert and novice assessors, and intra-rater variability) of a) the gastric antral cross-sectional area (CSA) and b) gastric volume using the Perlas US qualitative grading assessment, measured by using an ultrasound device in pediatric patients undergoing general anesthesia for elective surgery?
  • What is the correlation between ultrasound assessment of gastric emptying by the antral-CSA and gastric emptying determined by the acetaminophen absorption test (AAT), the gold standard?

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.

  • Cohort 1 will include abdominal ultrasound for gastric assessment AND the acetaminophen absorption test which includes administering enteral acetaminophen (tylenol) with 6 oz of water and drawing of blood samples through a peripheral intravenous line.
  • Cohort 2 will include subjects for whom a peripheral intravenous line placement is not part of routine pre-operative care. Procedures for Cohort 2 will include abdominal ultrasound only in the pre-op area (no tylenol). This cohort is included to examine the reliability of measurements across age groups.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

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Intervention / Treatment

Intervention / Treatment

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Study Type

Study Type

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Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
60

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

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Study Contact Backup

Study Locations

Participation Criteria

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Eligibility Criteria

Eligibility Criteria

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Ages Eligible for Study

2 years to 18 years (Child, Adult)

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

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.

Description

Inclusion Criteria:

  • Perioperative patients with ASA classification 1-2
  • Ages: 2 years- less than 18 years
  • Locations: Longwood and Waltham campuses of Boston Childrens Hospital

Exclusion Criteria:

  • History of gastrointestinal surgery
  • Gastrostomy
  • Known GI dysmotility (cohort 1 only)
  • Acetaminophen allergy (cohort 1 only)
  • Liver or renal dysfunction- pre-diagnosed or, if available, when serum biomarkers are 2 standard deviations above the highest value considered normal for age. (cohort 1 only)
  • Consumption of acetaminophen in the 4 hours prior (cohort 1 only)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Cohort
  • Time Perspectives: Prospective

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Cohort 1 - ultrasound and acetaminophen
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
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.
Diagnostic test: Acetaminophen Absorption Test (AAT)

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.

Diagnostic test: Gastric Ultrasound Serial Scans
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.
Cohort 2 - ultrasound only
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.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Inter-rater reliability
Time Frame: 1 year

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)
1 year
Intra-rater reliability
Time Frame: 1 year

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.
1 year
Gastric Emptying
Time Frame: 1 year
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.
1 year

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Post-anesthetic outcomes
Time Frame: 1 year
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).
1 year

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Boston Children's Hospital

Publications and helpful links

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General Publications

Study record dates

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Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
February 1, 2023

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 18, 2022

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 5, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 6, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 2, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 27, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • IRB-P00040829

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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