Preoperative Gastric Ultrasound to Assess Stomach Contents and Aspiration Risk in Patients With Diabetes

Distribution of Residual Gastric Volume Assessed by Preoperative Gastric Ultrasound, Aspiration Risk, and Related Factors in Diabetic Patients Undergoing Elective Surgery: A Prospective Observational Study

Diabetes can slow down stomach emptying. As a result, some patients with diabetes may still have food or fluid in their stomach before surgery, even after following standard fasting rules. This can increase the risk of stomach contents entering the lungs (pulmonary aspiration) during anesthesia.

The aim of this prospective observational study is to measure the amount of residual stomach content using bedside gastric ultrasound in adult patients with type 1 or type 2 diabetes scheduled for elective surgery under general anesthesia. The study will also determine how often a high aspiration risk is present and identify clinical factors associated with it, including HbA1c level, duration of diabetes, use of GLP-1 receptor agonists, insulin use, fasting duration, and gastroparesis symptoms.

Gastric ultrasound is non-invasive, painless, and does not involve radiation. No drug or additional intervention will be given as part of this study. Patients found to be at high aspiration risk will be reported to the responsible anesthesiologist.

Study Overview

• Status: Not yet recruiting
• Conditions: Respiratory Aspiration; Gastroparesis; Diabetes Mellitus ( Type 1 and Type 2)
• Intervention / Treatment: Diagnostic test: Preoperative Gastric Ultrasound

Detailed Description

This is a prospective, observational, single-center study to be conducted at the University of Health Sciences Gazi Yasargil Training and Research Hospital. Approximately 130 adult patients (aged 18-80 years, ASA physical status I-III) with type 1 or type 2 diabetes mellitus scheduled for elective surgery under general anesthesia will be enrolled after written informed consent.

Each patient will be assessed at a single time point in the preoperative holding area before induction of anesthesia. Gastric ultrasound will be performed in the supine and right lateral decubitus positions. The anteroposterior and craniocaudal diameters of the gastric antrum will be measured, and the antral cross-sectional area (CSA) will be calculated. Gastric volume (GV) will be estimated using the Perlas formula [GV (mL) = 27 + 14.6 x CSA - 1.28 x age] and normalized to body weight (mL/kg). Gastric content will be classified according to the Perlas grading system (Grade 0-2). Patients with Perlas Grade 2 and/or GV >1.5 mL/kg will be classified as having high aspiration risk.

Demographic data, diabetes-related clinical parameters (type and duration of diabetes, HbA1c, fasting blood glucose, insulin and oral antidiabetic use), details of GLP-1 receptor agonist use (drug, dose, frequency, and time since last dose), preoperative fasting durations, and gastroparesis symptoms assessed with the Gastroparesis Cardinal Symptom Index (GCSI) will be recorded by a second investigator.

To minimize measurement bias, the ultrasound examination will be performed by a single trained anesthesiologist blinded to the patients' clinical data, while the investigator collecting clinical data will be blinded to the ultrasound findings.

Patients will be followed for 24-48 hours postoperatively through medical records for postoperative nausea and vomiting, fever, cough, dyspnea, pulmonary infiltrates on chest radiography, and clinical signs of aspiration pneumonia.

Factors associated with high aspiration risk will be analyzed using univariable and multivariable logistic regression. Correlations between gastric volume and HbA1c, diabetes duration, fasting duration, and GCSI score will be assessed using Pearson or Spearman correlation.

• Study Type: Observational
• Enrollment (Estimated): 130

Contacts and Locations

• Study Contact: Name: RENİM YÜKSEL, MD; Phone Number: +90 0538 474 80 39; Email: renimbarut@hotmail.com

Study Locations

• Turkey (Türkiye)
  • Diyarbakır
    • Diyarbakır, Diyarbakır, Turkey (Türkiye), 21070
      • University of Health Sciences Gazi Yasargil Training and Research Hospital
      • Contact: RENİM YUKSEL, MD; Phone Number: +90 0538 474 80 39; Email: renimbarut@hotmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Adult patients with type 1 or type 2 diabetes mellitus scheduled for elective surgery under general anesthesia at the University of Health Sciences Gazi Yasargil Training and Research Hospital.

Description

Inclusion Criteria:

• Age 18-80 years
• Diagnosis of type 1 or type 2 diabetes mellitus
• Scheduled for elective surgery under general anesthesia
• ASA physical status I-III
• Written informed consent

Exclusion Criteria:

• Emergency surgery
• Pregnancy
• History of upper gastrointestinal surgery
• Known gastrointestinal obstruction
• Known severe gastroparesis
• Inadequate gastric ultrasound image quality
• Refusal to provide consent

Study Plan

How is the study designed?

Design Details

• Observational Models: COHORT
• Time Perspectives: PROSPECTIVE

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Diabetic Patients Undergoing Elective Surgery; dult patients (18-80 years, ASA physical status I-III) with type 1 or type 2 diabetes mellitus scheduled for elective surgery under general anesthesia, who will undergo a single preoperative gastric ultrasound assessment and 24-48 hours of postoperative follow-up for clinical signs of aspiration.

Diagnostic test: Preoperative Gastric Ultrasound; Bedside gastric ultrasound performed in the supine and right lateral decubitus positions in the preoperative holding area before induction of anesthesia. The antral cross-sectional area will be measured, gastric volume will be calculated using the Perlas formula and normalized to body weight (mL/kg), and gastric content will be classified using the Perlas grading system. The examination is non-invasive and part of a single assessment; no drug or treatment is administered.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Residual Gastric Volume Assessed by Preoperative Gastric Ultrasound	Gastric ultrasound will be performed in both the supine and right lateral decubitus positions. Gastric volume will be estimated from the antral cross-sectional area measured in the right lateral decubitus position using the Perlas formula [GV (mL) = 27 + 14.6 x CSA - 1.28 x age] and normalized to body weight (mL/kg). The distribution of residual gastric volume will be reported as mean, standard deviation, median, interquartile range, and minimum-maximum values.	Preoperatively, before induction of anesthesia (single assessment)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prevalence of High Aspiration Risk	Proportion of patients classified as having high aspiration risk, defined as Perlas Grade 2 (fluid visible in both supine and right lateral decubitus positions) and/or gastric volume >1.5 mL/kg. Prevalence will be reported with 95% confidence interval	Preoperatively, before induction of anesthesia (single assessment)
Correlation Between HbA1c and Gastric Volume	Correlation between preoperative HbA1c level (%) and weight-normalized gastric volume (mL/kg), assessed using Pearson or Spearman correlation coefficient.	Preoperatively, before induction of anesthesia (single assessment)
Correlation Between Diabetes Duration and Gastric Volume	Correlation between duration of diabetes mellitus (years) and weight-normalized gastric volume (mL/kg), assessed using Pearson or Spearman correlation coefficient.	Preoperatively, before induction of anesthesia (single assessment)
Effect of GLP-1 Receptor Agonist Use and Timing of Last Dose on Gastric Volume	Weight-normalized gastric volume (mL/kg) compared between GLP-1 receptor agonist users and non-users. Among users, gastric volume will be compared between patients whose last dose was taken ≤7 days and >7 days before the preoperative assessment	Preoperatively, before induction of anesthesia (single assessment)
Effect of Insulin Use on Gastric Volume	Weight-normalized gastric volume (mL/kg) compared between patients using and not using insulin therapy.	Preoperatively, before induction of anesthesia (single assessment)
Correlation Between Preoperative Fasting Duration and Gastric Volume	Correlation between preoperative solid and clear fluid fasting durations (hours) and weight-normalized gastric volume (mL/kg), assessed using Pearson or Spearman correlation coefficient.	Preoperatively, before induction of anesthesia (single assessment)
Correlation Between Gastroparesis Cardinal Symptom Index (GCSI) Score and Gastric Volume	Correlation between total GCSI score (range 0-5, higher scores indicate more severe gastroparesis symptoms) and weight-normalized gastric volume (mL/kg), assessed using Pearson or Spearman correlation coefficient.	Preoperatively, before induction of anesthesia (single assessment)
Incidence of Postoperative Clinical Aspiration	Number of patients developing clinical signs of pulmonary aspiration (fever, cough, dyspnea, new pulmonary infiltrate on chest radiography) or aspiration pneumonia, and postoperative nausea and vomiting, assessed from medical records.	Up to 48 hours after surgery

Collaborators and Investigators

• Sponsor: Saglik Bilimleri Universitesi Gazi Yasargil Training and Research Hospital
• Investigators: Principal Investigator: RENİM YÜKSEL, MD, University of Health Sciences, Gazi Yasargil Training and Research Hospital

Publications and helpful links

General Publications

• Perlas A, Mitsakakis N, Liu L, Cino M, Haldipur N, Davis L, Cubillos J, Chan V. Validation of a mathematical model for ultrasound assessment of gastric volume by gastroscopic examination. Anesth Analg. 2013 Feb;116(2):357-63. doi: 10.1213/ANE.0b013e318274fc19. Epub 2013 Jan 9.
• Perlas A, Chan VW, Lupu CM, Mitsakakis N, Hanbidge A. Ultrasound assessment of gastric content and volume. Anesthesiology. 2009 Jul;111(1):82-9. doi: 10.1097/ALN.0b013e3181a97250.

Study record dates

Study Major Dates

• Study Start (Estimated): December 15, 2026
• Primary Completion (Estimated): June 30, 2027
• Study Completion (Estimated): June 30, 2027

Study Registration Dates

• First Submitted: November 4, 2026
• First Submitted That Met QC Criteria: November 4, 2026
• First Posted (Actual): November 10, 2026

Study Record Updates

• Last Update Posted (Actual): November 10, 2026
• Last Update Submitted That Met QC Criteria: November 4, 2026
• Last Verified: November 1, 2026

More Information

Terms related to this study

• Keywords: Point-of-Care Ultrasound; Gastric Ultrasound; Preoperative Fasting; GLP-1 Receptor Agonists; Aspiration Risk; Residual Gastric Volume
• Additional Relevant MeSH Terms: Neurologic Manifestations; Endocrine System Diseases; Pathologic Processes; Metabolic Diseases; Respiratory Tract Diseases; Digestive System Diseases; Gastrointestinal Diseases; Stomach Diseases; Respiration Disorders; Glucose Metabolism Disorders; Paralysis; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Diabetes Mellitus; Respiratory Aspiration; Gastroparesis
• Other Study ID Numbers: 441

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

IPD Plan Description

Individual participant data will not be shared due to patient confidentiality and data protection regulations. Aggregate results will be reported in the publication.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No