Stomach Processing and Emptying Evaluation With Diet and Ultrasound (SPEED-US)

Medical University of Warsaw

Status: Not yet enrolling

Conditions: Gastric Emptying; Preoperative Risk Assessment; Healthy Volunteer Study

Treatments: Behavioral: Physical activity after different type of meals

Study type: Interventional

Funder types: Other

Identifiers

NCT06988397

KB/6/2025

Details and patient eligibility

About

Gastric content is a key risk factor for aspiration during anesthesia. Although standard fasting times are recommended, various factors-including GLP-1 receptor agonists,-can delay gastric emptying. Gastric ultrasound enables real-time, non-invasive assessment of gastric volume and can help tailor perioperative management. The aim of this study explores the effects of different meal types and physical activity on gastric emptying in healthy individuals.

Full description

Pulmonary aspiration of gastric contents is a serious and potentially life-threatening complication of anesthesia. Despite adherence to preoperative fasting guidelines issued by the American Society of Anesthesiologists (ASA), certain medical conditions-such as diabetes mellitus-or medications like GLP-1 receptor agonists may significantly delay gastric emptying beyond standard expectations. This creates a need for individualized assessment of gastric contents prior to anesthesia, especially in patients considered at increased risk.

Gastric ultrasound is a non-invasive, point-of-care technique that allows for real-time assessment of gastric volume and content. It may provide a more reliable indicator of aspiration risk than fasting time alone.

This randomized, prospective study aims to evaluate the effects of different types of meals and physical activity levels on gastric emptying time in healthy adult volunteers, using ultrasound-based measurement of the gastric antrum.

Sixty participants aged 18-40 years will be recruited via registration forms provided by the study team. Each participant will provide written informed consent, including acknowledgment of potential food allergens present in the study meals. The day prior to each session, participants will receive a phone call to remind them of dietary restrictions: no clear liquids for 2 hours, no solid foods for 6 hours, and no fatty meals for 8 hours before the study.

Each participant will take part in two separate sessions, conducted on different days. On both days, the participant will arrive fasting and undergo a baseline gastric ultrasound to confirm an empty stomach. If gastric content is detected, the session will be rescheduled.

Participants will be randomly assigned (via computer-generated allocation) to one of three meal groups: high-fat, dairy-based, or fruit/vegetable. Meals will be standardized in volume and composition within each group. The examiner performing the ultrasound will be blinded to the meal group allocation.

In each session, participants will consume the assigned meal within 10 minutes. Gastric ultrasound measurements will be performed at 15 minutes, 3 hours, and 6 hours post-meal. On one of the days, participants will remain in a resting position between measurements. On the other day, participants will walk at a moderate pace for 30 minutes between each measurement interval (i.e., between 0-3 hours and 3-6 hours post-meal). The order of active vs. resting day will be randomized and counterbalanced across participants.

Ultrasound will be performed in the right lateral decubitus position using a convex transducer (2-8 MHz) with an abdominal preset. The antral cross-sectional area (CSA) will be measured using standard landmarks (aorta, SMA, left lobe of liver), and gastric volume will be estimated using a validated formula:

GV = 27.0 + 14.6 × right lateral CSA (cm²) - 1.28 × age (years).

Enrollment: 60 estimated patients

Sex: All

Ages: 18 to 40 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Age between 18 and 40 years
• Ability and willingness to provide written informed consent
• Agreement to comply with study procedures, including pre-study dietary restrictions
• No history of gastrointestinal disease
• No recent abdominal surgery

Exclusion criteria

• Lack of informed consent
• Allergy or intolerance to any of the foods used in the study meals
• Medical conditions known to delay gastric emptying, including:
• Obesity (BMI > 30 kg/m²)
• Diabetes mellitus
• Gastroesophageal reflux disease (GERD)
• Hiatal hernia
• Bowel obstruction
• Tube feeding
• Active gastrointestinal disease
• History of gastrointestinal surgery
• Current pregnancy or breastfeeding
• Use of medications affecting gastric motility (e.g., opioids, anticholinergics, GLP-1 receptor agonists)
• Neuromuscular disorders impairing ability to remain in supine position for 6 hours or to walk for 30 minutes

Trial design

Primary purpose: Diagnostic

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Single Blind

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60 participants in 2 patient groups

Gastric Ultrasound in Participants Consuming Different Meal Types with Physical Acivity

Experimental group

Description:

Participants assigned to this arm will undergo an initial gastric ultrasound to confirm fasting status. They will then consume one of three types of meals: vegetable-based, meat-based, or dairy-based. A gastric ultrasound will be performed 15 minutes after meal ingestion. This will be followed by standardized physical activity (walking a predefined distance). Subsequent gastric ultrasound assessments will be performed at 3 hours and 6 hours post-meal, each followed by the same standardized physical activity. The purpose is to evaluate the impact of food type and intermittent physical activity on gastric emptying, as assessed by ultrasound.

Treatment:

Behavioral: Physical activity after different type of meals

Gastric Ultrasound in Participants Consuming Different Meal Types with Subsequent Rest

No Intervention group

Description:

Participants in this arm will first undergo a baseline gastric ultrasound to confirm fasting status. They will then consume one of three types of meals: vegetable-based, meat-based, or dairy-based. Gastric ultrasound will be performed 15 minutes after meal ingestion. Unlike the other arm, participants in this group will remain at rest throughout the study period and will not perform any physical activity. Additional gastric ultrasound assessments will be performed at 3 hours and 6 hours post-meal, with participants remaining sedentary between each measurement. This arm will serve to assess the isolated effect of food type on gastric emptying over time without the influence of physical activity.