The aim of this study is to determine whether the fasting duration required for patients after consuming oral jelly is comparable to that after consuming water, prior to elective surgery.

International guidelines for perioperative fasting recommend abstaining from clear fluids for 2 hours to minimize the risk of regurgitation and aspiration pneumonia. However, there are no specific recommendations regarding the perioperative management of jelly consumption.

Current understanding emphasizes the benefits of minimizing preoperative fasting time, including preventing dehydration and metabolic complications like ketoacidosis, as well as potentially enhancing patient satisfaction.

Oral jelly consumption may offer advantages by improving preoperative hydration and providing some nutritional support prior to procedures.

This crossover study will involve 25 adult volunteers. In the first phase, participants will be randomly assigned to either oral intake of water or jelly, followed by the opposite intervention in the second phase. Gastric content and volume will be assessed using gastric ultrasound.

Prolonged preoperative fasting is associated with unfavorable outcomes, inducing a catabolic state that may lead to metabolic disturbances such as ketoacidosis, insulin resistance, dehydration, and increased postoperative complications such as surgical site infection and delayed bowel function. To minimize fasting time, current guidelines from the American Society of Anesthesiology advise clear fluid intake (water, tea, coffee, pulp-free fruit juices, carbohydrate-rich beverages) up to 2 hours prior to elective procedures involving general anesthesia, regional anesthesia, or procedural sedation and analgesia. Solids fasting should extend to 6 to 8 hours, depending on the type of foods.

Jelly is a solid food, mostly composed of water. Among its other components, proteins, responsible for its solidification, and sugars stand out. Thus, it may be a form of oral hydration, associated with some nutritional value, but the appropriate preoperative fasting time is not explicitly stated in the guidelines.

An important cause of mortality and morbidity associated with tracheal intubation is the aspiration of gastric contents. It is important to ensure that restricting preoperative fasting time does not compromise patient safety, thereby increasing this risk. While carbohydrate-rich beverages are not associated with delays in gastric emptying, the same cannot be said for protein-containing liquids.

Gastric ultrasound is a non-invasive, bedside-available, and reliable method for quantitative and qualitative assessment of stomach contents. Although the minimum volume of gastric contents associated with increased risk of aspiration is not known, some studies demonstrate that volumes up to 1.5 mL/kg of clear fluids, in the absence of solid contents, are normal, commonly seen in fasting adults, and are not associated with an increased risk of pulmonary aspiration.

The aim of our study is to demonstrate that jelly ingestion, compared to water, is not associated with larger cross-sectional area of the gastric antrum, behaving similarly to clear fluids.

Inclusion Criteria:

• Adult volunteers working in the hospital Centro Hospitalar de Entre o Douro e Vouga (CHEDV)

Exclusion Criteria:

• morbid obesity
• pregnancy
• alcohol abuse
• diseases or drugs that can prolong or accelerate gastric emptying such as gastric or esophageal surgery, diabetes mellitus, prokinetic or opioid use, hypothyroidism
• intolerance to any of the components of jelly