Impact of Body Positioning on EndoFLIP Measurements: A Comparative Study of Supine and Left Lateral Decubitus Positions

August 19, 2026 updated by: Johns Hopkins University
This is a prospective, single-center, crossover study comparing EndoFLIP measurements obtained in two patient positions, supine and left lateral decubitus, in pediatric and young adult patients. The Endoluminal Functional Lumen Imaging Probe (EndoFLIP) is an FDA-approved device for patients aged 5 and older that utilizes high-resolution impedance planimetry and volume-controlled distension to assess esophagogastric junction function. Currently, no standardized positioning protocol exists, and proceduralists perform EndoFLIP based on individual preference, either supine or left lateral decubitus. This variability may introduce measurement inconsistencies, particularly when comparing preoperative and postoperative assessments performed in different positions.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

The Endoluminal Functional Lumen Imaging Probe (EndoFLIP) is an FDA-approved device for patients aged 5 years and older and it utilizes high-resolution impedance planimetry and volume-controlled distension to evaluate the GI lumen including the esophagogastric junction. EndoFLIP has become an invaluable tool in pediatric gastroenterology helping to characterize various luminal conditions including but not limited to esophageal stenosis and compression, screening for dysmotility, guiding esophageal dilation through the selection of the optimal dilator size, among others. Despite its increasing clinical utility, there is currently no standardized protocol for its use and much of the technique is derived from adult practice.

Proceduralists perform measurements based on individual preference, with some favoring the supine position and others preferring the left lateral decubitus position. This lack of consensus has been an active topic of discussion among pediatric advanced endoscopists who perform EndoFLIP, yet no published studies exist comparing measurements obtained in different positions. This variability presents a significant clinical problem because positioning may influence EndoFLIP parameters through several physiological mechanisms. In the supine position, abdominal viscera shift posteriorly, potentially altering esophagogastric junction geometry and increasing intra-abdominal pressure. In the left lateral decubitus position, the gastric fundus falls away from the esophagogastric junction due to gravity, possibly reducing external compression and changing the angle of His. Additionally, diaphragmatic crural tension, thoracic mechanics, and vascular engorgement patterns may differ between positions, all of which could affect luminal measurements. These positional differences have important clinical implications, particularly when comparing preoperative and postoperative measurements, assessing dilation durability within the same procedure, or monitoring disease progression longitudinally over multiple visits. If measurements are obtained in different positions across these clinical scenarios, apparent changes in esophagogastric junction function may be artifactual rather than reflective of true physiological change.

The investigators hypothesize that patient positioning, supine versus left lateral decubitus, impacts EndoFLIP measurements. This is a non-directional hypothesis, as there is currently insufficient evidence to predict whether measurements will be higher or lower in one position compared to the other.

Study Type

Interventional

Enrollment (Estimated)

25

Phase

  • Not Applicable

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

  • Name: Kenneth Ng, DO
  • Phone Number: 410-955-8769
  • Email: kng13@jhmi.edu

Study Contact Backup

  • Name: Ningfei Li, MD
  • Phone Number: 4109556070
  • Email: nli56@jh.edu

Study Locations

  • United States
    • Maryland
      • Baltimore, Maryland, United States, 21287
        • Recruiting
        • Charlotte R. Bloomberg Children's Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • must be between 5 years and 21 years of age at the time of the procedure, which is within the FDA-approved age range for EndoFLIP use.
  • participants must be scheduled to undergo a clinically indicated EndoFLIP procedure at Johns Hopkins Children's Center.
  • participants must have a parent or legal guardian who is able to provide written informed consent in English, or with the assistance of translation services for non-English speakers.
  • participants who are of appropriate age and developmental capacity must be able to provide assent for study participation.
  • participants must be candidates for general anesthesia as determined by the anesthesia team.

Exclusion Criteria:

  • patients younger than 5 years of age or 22 years of age and older will be excluded.
  • patients who have contraindications to EndoFLIP will be excluded, including situations where upper endoscopy is generally contraindicated such as known or suspected gastrointestinal perforation, hemodynamic instability, severe coagulopathy, or inability to safely undergo general anesthesia.
  • patients who cannot be safely positioned in both supine and left lateral decubitus positions due to medical or anatomical considerations will be excluded.
  • pregnant patients will be excluded. Pregnancy status will be determined by patient or guardian report and, when clinically indicated, by urine or serum pregnancy testing per institutional protocols for patients of childbearing potential.
  • patients whose parent or legal guardian declines to provide informed consent or patients who decline to provide assent when age-appropriate will be excluded.
  • patients for whom the proceduralist or anesthesia team determines that participation in the research protocol would pose additional risk beyond routine clinical care will be excluded.

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

  • Primary Purpose: Diagnostic
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Left lateral position first, supine position second
Diagnostic test: EndoFlip
The Endoluminal Functional Lumen Imaging Probe (EndoFLIP) is an FDA-approved device for patients aged 5 years and older and it utilizes high-resolution impedance planimetry and volume-controlled distension to evaluate the GI lumen.
Other: supine position first, Left lateral position second
Diagnostic test: EndoFlip
The Endoluminal Functional Lumen Imaging Probe (EndoFLIP) is an FDA-approved device for patients aged 5 years and older and it utilizes high-resolution impedance planimetry and volume-controlled distension to evaluate the GI lumen.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Diameter
Time Frame: During procedure only (less than 10 minutes)
Diameter of esophagus (mm)
During procedure only (less than 10 minutes)
Cross sectional area
Time Frame: During procedure only (less than 10 minutes)
Esophageal cross sectional area measured in square millimeters (mm²)
During procedure only (less than 10 minutes)
Compliance
Time Frame: During procedure only (less than 10 minutes)
esophageal compliance (mm3/mmHg)
During procedure only (less than 10 minutes)
distensibility index
Time Frame: During procedure only (less than 10 minutes)
esophageal distensibility index(mm2/mmHg)
During procedure only (less than 10 minutes)
Pressure
Time Frame: During procedure only (less than 10 minutes)
intraluminal esophageal pressure (mmHg)
During procedure only (less than 10 minutes)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Differences in diameter
Time Frame: During procedure only (less than 10 minutes)
calculated difference in diameter between supine vs left lateral position (mm), percentage difference from left lateral position to supine position and also supine to left lateral position
During procedure only (less than 10 minutes)
Differences in Cross sectional area
Time Frame: During procedure only (less than 10 minutes)
calculated difference in Cross sectional area between supine vs left lateral position (mm2), percentage difference from left lateral position to supine position and also supine to left lateral position
During procedure only (less than 10 minutes)
Differences in esophageal compliance (mm3/mmHg)
Time Frame: During procedure only (less than 10 minutes)
calculated difference in esophageal compliance (mm3/mmHg) between supine vs left lateral position, percentage difference from left lateral position to supine position and also supine to left lateral position
During procedure only (less than 10 minutes)
Differences in esophageal distensibility index(mm2/mmHg)
Time Frame: During procedure only (less than 10 minutes)
calculated difference in esophageal distensibility index(mm2/mmHg) between supine vs left lateral position, percentage difference from left lateral position to supine position and also supine to left lateral position
During procedure only (less than 10 minutes)
Differences in intraluminal esophageal pressure (mmHg)
Time Frame: During procedure only (less than 10 minutes)
calculated difference in intraluminal esophageal pressure (mmHg) between supine vs left lateral position, percentage difference from left lateral position to supine position and also supine to left lateral position
During procedure only (less than 10 minutes)

Collaborators and Investigators

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

Sponsor

Johns Hopkins University

Investigators

  • Principal Investigator: Kenneth Ng, DO, Johns Hopkins University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

July 24, 2026

Primary Completion (Estimated)

July 1, 2027

Study Completion (Estimated)

July 1, 2028

Study Registration Dates

First Submitted

August 19, 2026

First Submitted That Met QC Criteria

August 19, 2026

First Posted (Actual)

August 24, 2026

Study Record Updates

Last Update Posted (Actual)

August 24, 2026

Last Update Submitted That Met QC Criteria

August 19, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • IRB00560539

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

Yes

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.

Subscribe