Does Pre-operative Gastric Ultrasound Influence Anaesthetic Decision-Making in Chronic Pain Patients? A Prospective Observational Cohort.

April 17, 2026 updated by: JINAN AHMED JAMEEL AL ALOOSI, Danat Al Emarat Hospital

Does Pre-operative Gastric Ultrasound Influence Anaesthetic Decision-Making in Chronic Pain Patients? A Prospective Observational Cohort Study

Gastric POCUS has been validated and shown to be an accurate diagnostic tool in both healthy individuals and medically complex patient populations. Regional anaesthesiologists and pain management physicians frequently provide sedation or anaesthetic care for medically complex patients who fall outside the limited applicability of existing fasting guidelines, including patients with chronic pain, poor acute-on-chronic pain control, and those receiving acute or chronic opioid therapy. These patients are at risk of delayed gastric emptying and may therefore benefit from additional pre-procedural assessment using gastric ultrasound prior to elective interventions

Study Overview

Status

Not yet recruiting

Conditions

Detailed Description

This study is the first prospective evaluation of gastric ultrasound in this high-risk, understudied population, incorporating quantitative opioid exposure and focusing on its impact on real-time anaesthetic decision-making. By linking gastric ultrasound findings to changes in peri-procedural management, this work extends gastric POCUS from a diagnostic tool to a clinically actionable risk-stratification strategy.

The aim of this study is to determine whether pre-operative gastric POCUS provides decision-relevant information that influences peri-operative aspiration risk assessment and leads to modification of pre-defined anaesthetic management plans in chronic pain patients undergoing elective interventional procedures under sedation.

Pre-procedural gastric ultrasound will be performed immediately before initiation of sedation by the investigators experienced in gastric point-of-care ultrasound, each having completed at least 30 supervised examinations. A standardised scanning protocol was used. Qualitative assessment of gastric contents was performed in the supine position and in the right lateral decubitus position. When patient-related factors precluded these positions, scanning was performed in a semi-recumbent position at approximately 45°.

Gastric contents will be classified qualitatively as:

  • Empty
  • Fluid (homogeneous hypoechoic contents)
  • Solid or mixed (heterogeneous contents with echogenic material) When fluid content was identified, the gastric antral cross-sectional area (CSA) was measured at rest in a parasagittal plane at the level of the abdominal aorta using the serosal tracing method, as previously described. Gastric fluid volume was estimated using the validated Perlas mathematical model.

In accordance with current literature and consensus recommendations, patients with solid or mixed gastric contents were classified as having a high aspiration risk. For patients with fluid contents, a gastric volume threshold of >1.5 ml·kg-¹ body weight was used to define high aspiration risk. Patients with an empty stomach or fluid volumes ≤1.5 ml·kg-¹ were classified as low risk.

Following completion of gastric ultrasound and prior to initiation of sedation, the responsible anaesthetist reassessed the patient's aspiration risk incorporating the ultrasound findings. The anaesthetist documented whether the original anaesthetic management plan was:

  • Unchanged
  • Modified to a more conservative approach (additional measures to reduce aspiration risk)
  • Modified to a more liberal approach Anaesthetic management modifications were made at the discretion of the responsible anaesthesiologist to ensure patient safety. The anesthesiologist responsible for patient care will not be blinded to ultrasound findings, consistent with the observational nature of the study.

Study Type

Observational

Enrollment (Estimated)

140

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 Backup

Study Locations

  • United Arab Emirates
    • Abu Dhabi Emirate
      • Abu Dhabi, Abu Dhabi Emirate, United Arab Emirates
        • Danat Al Emarat Women & Children Hospital
        • Contact:
        • Contact:
        • Principal Investigator:
          • Waleed Riad, Pain medicine Anesthesiologist
        • Principal Investigator:
          • JINAN JAMEEL AL ALOOSI, Consultant Anesthesiologist

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

This will be a single-center, prospective observational cohort study conducted at Danat Al Emarat Hospital, Abu Dhabi, UAE. Adult patients scheduled for elective chronic pain interventional procedures under procedural sedation will be screened for eligibility.

Description

Inclusion Criteria: Patients were eligible for inclusion if they met all of the following criteria:

  • Age ≥18 years
  • Scheduled for elective chronic pain interventional procedures under procedural sedation
  • Adherence to standard preoperative fasting guidelines (≥6 hours for clear fluids and ≥8 hours for solids)
  • Presence of at least one clinical factor associated with delayed gastric emptying or increased risk of pulmonary aspiration, including:
  • Chronic opioid use (≥2 weeks)
  • Acute opioid administration within 24 hours prior to the procedure
  • Poorly controlled acute-on-chronic pain
  • Diabetes mellitus without established autonomic neuropathy
  • Symptoms of gastroesophageal reflux
  • Reduced functional mobility
  • ASA physical status II-III

Exclusion Criteria: Patients will be excluded if any of the following present:

  • Age <18 years
  • Previous gastric or esophageal surgery
  • Known pregnancy
  • Known hiatal hernia
  • Severe neurological disorders affecting swallowing or gastric motility
  • Established autonomic neuropathy affecting gastric emptying (e.g. advanced diabetic gastroparesis)
  • Morbid obesity (body mass index ≥35 kg·m-²), due to known limitations in gastric ultrasound image acquisition and reduced validity of volume estimation models
  • Inability to provide informed consent

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

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
The proportion of patients in whom pre-procedural gastric ultrasound resulted in a change to the pre-defined anesthetic management plan.
Time Frame: 1- 2 hours
The Percentage of patients from the total number of patients involved in the study, in whom pre-procedural gastric ultrasound reveals signs of high aspiration risk which needed a change to the pre-defined anesthetic management plan, A management change was defined as any deviation from the originally documented sedation or airway strategy following review of ultrasound findings. (Patients with solid or mixed gastric contents, or fluid contents with a gastric volume of >1.5 ml·kg-¹ body weight are classified as having a high aspiration risk).
1- 2 hours

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Prevalence of high-risk gastric contents despite adherence to fasting guidelines
Time Frame: 1- 2 hours
Prevalence of number of patients in our study who were fasting in accordance with fasting guidelines, and in whom pre-procedural gastric ultrasound reveals solid / mixed gastric contents or a fluid content, with a gastric volume of >1.5 ml·kg-¹ body weight, which used to define a high aspiration risk.
1- 2 hours
Associations between gastric ultrasound findings and patient-related factors, including opioid use and comorbidities
Time Frame: 1-2 hours
To point out the effect and relation of each of the risk factors included in our study (e.g. Opioid use and comorbidities in chronic pain patients), on gastric contents & volume, in the studied patients after fasting period in accordance with fasting guidelines.
1-2 hours
Qualitative and quantitative gastric ultrasound findings
Time Frame: 1-2 hours

To describe the gastric ultrasound finding; Gastric contents will be classified qualitatively as; Empty, Fluid (homogeneous hypoechoic contents), Solid or mixed (heterogeneous contents with echogenic material).

Qualitative findings: When fluid content is identified, the gastric antral cross-sectional area (CSA) is measured at rest in a parasagittal plane at the level of the abdominal aorta. Gastric fluid volume is estimated using the validated Perlas mathematical model.
1-2 hours

Collaborators and Investigators

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

Sponsor

Danat Al Emarat Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 (Estimated)

April 1, 2026

Primary Completion (Estimated)

April 1, 2027

Study Completion (Estimated)

August 1, 2027

Study Registration Dates

First Submitted

March 12, 2026

First Submitted That Met QC Criteria

April 16, 2026

First Posted (Actual)

April 17, 2026

Study Record Updates

Last Update Posted (Actual)

April 22, 2026

Last Update Submitted That Met QC Criteria

April 17, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • RPDAE/2026/102

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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