An interventional study of Three-hour fasting after yoghurt breakfast and Four-hour fasting after yoghurt breakfast in Preoperative Fasting, sponsored by Baskent University Ankara Hospital. Not yet recruiting at 1 site in Turkey (Türkiye). Open to participants aged 1 Year to 10 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-08.
Sponsored by Baskent University Ankara Hospital · Not applicable, Interventional, and Basic science
Children are asked to fast before anaesthesia to reduce the amount of material remaining in the stomach. Prolonged fasting can cause hunger, thirst and discomfort. Although shorter fasting intervals have been introduced for clear fluids and breast milk, less is known about how quickly a light yoghurt breakfast leaves the stomach. Yoghurt differs from clear fluids in its nutrient content and semi-solid consistency.
The primary aim of this study is to compare gastric emptying after three versus four hours of fasting following yoghurt intake in 24 children aged 1 to 10 years undergoing elective upper gastrointestinal endoscopy under anaesthesia at Baskent University Faculty of Medicine Ankara Hospital. Children will be randomly allocated to two equal groups. They may eat yoghurt freely up to a maximum of 150 g; there is no prescribed fixed or weight-based dose, and the amount actually eaten will be recorded.
Ultrasound will assess stomach contents at the assigned fasting interval. If the stomach has not emptied according to the study criterion, the assessment will be repeated at 10-minute intervals before proceeding with anaesthesia. Gastric contents will also be assessed directly during endoscopy. The clinicians performing ultrasound and endoscopy will not know the assigned group; the anaesthetist will know it.
The primary outcome is the proportion of children with an empty stomach at the first ultrasound assessment, compared between the three-hour and four-hour groups. The primary hypothesis is that a three-hour interval after yoghurt intake will yield a similar proportion of empty stomachs to a four-hour interval. Secondary outcomes include estimated gastric volume, endoscopic findings, hunger, and agreement between ultrasound and endoscopic assessment.
Background and rationale
Preoperative fasting in children aims to reduce residual gastric contents while avoiding the adverse effects of unnecessarily prolonged restriction of oral intake. Hunger, thirst, discomfort and metabolic disturbances provide a rationale for investigating shorter fasting intervals. European paediatric fasting recommendations have increasingly supported shorter intervals for clear fluids and breast milk. These developments do not establish an appropriate fasting interval for semi-solid foods, whose emptying may depend on the amount ingested, energy density and nutrient composition.
Yoghurt is a familiar food for children and a potential component of a light preoperative breakfast. Its semi-solid structure and macronutrient content distinguish it from clear fluids. Previous paediatric studies of light breakfasts, including yoghurt or gruel, have reported low residual gastric volumes in most children after approximately four hours, while also showing variability in gastric emptying. Whether a three-hour interval is sufficient after yoghurt intake remains uncertain. Upper gastrointestinal endoscopy provides an opportunity to assess intragastric contents directly alongside ultrasound findings.
Primary objective and hypothesis
The primary objective is to compare gastric emptying after three versus four hours of fasting following a yoghurt breakfast. This comparison will be evaluated using the proportion of children meeting the ultrasound empty-stomach criterion at the first assessment at their allocated fasting interval. The primary hypothesis is that the three-hour group will have a similar proportion of empty stomachs to the four-hour group. Similarity is a research hypothesis; no formal equivalence or non-inferiority margin has been specified.
Secondary objectives
Secondary objectives are to compare ultrasound-estimated gastric volume, endoscopic findings and hunger between the randomized groups, and to assess agreement between gastric ultrasonography and endoscopic assessment. Method agreement is a secondary analysis and does not determine the primary comparison of the two fasting intervals.
Design and setting
This is a prospective, single-centre, randomized, parallel-group pilot study at Baskent University Faculty of Medicine Ankara Hospital, Ankara, Turkey. Twenty-four children will be allocated in a 1:1 ratio to a three-hour or four-hour fasting group, with 12 participants per group. Planned study dates are 7 to 19 October 2026. Ahmed Uslu is the principal investigator. Ethics approval has been reported.
Participants and consent
Children aged 1 to 10 years, of either sex, with American Society of Anesthesiologists physical status I or II and scheduled for elective upper gastrointestinal endoscopy under anaesthesia will be eligible. Children with cardiac, respiratory or peripheral circulatory disorders, diabetes mellitus, or a condition that delays gastrointestinal transit will be excluded. Families will receive detailed information about the study, with age-appropriate information for children, and written informed consent will be obtained from a parent or legal guardian before enrollment. Preprocedure assessment and investigations will follow the hospital's usual practice.
Yoghurt intake and group allocation
Both groups will be permitted ad libitum yoghurt intake up to a maximum of 150 g. No fixed dose or weight-based quantity will be prescribed. The actual amount consumed will be recorded in grams. The randomized comparison concerns the planned interval between yoghurt ingestion and the first gastric ultrasound assessment: three hours in one group and four hours in the other. Actual fasting duration, the time of last water intake, body weight, age, and the times of ultrasound and endoscopy will be recorded. These records will describe variation in intake and the achieved assessment intervals.
Masking
The clinicians performing gastric ultrasonography and upper gastrointestinal endoscopy will be blinded to randomized fasting-group allocation. The anaesthetist will know the assigned group and oversee the timing of anaesthesia and the procedure. Masking refers to the outcome assessors; it does not mean that two different assessment procedures constitute two separate categories of masking.
Gastric ultrasound and procedural sequence
Standard monitoring will include electrocardiography, non-invasive blood pressure and pulse oximetry. Gastric ultrasonography will be performed before anaesthetic induction, with the child in the right lateral decubitus position. Two orthogonal antral diameters will be measured in triplicate. Antral cross-sectional area will be calculated using the ellipse formula, CSA = pi x A x B / 4, with diameters expressed in millimetres and area in square millimetres. The planned gastric volume estimate is GCV (mL/kg) = 0.0093 x CSA (mm2) - 0.96. This equation provides a weight-indexed volume, rather than an absolute volume in mL.
The supplied project summary defines an ultrasound volume below 1.5 mL/kg as meeting the empty-stomach criterion. If this criterion is not met, ultrasound assessment will be repeated at 10-minute intervals and anaesthesia will be deferred until the protocol criterion is met. The case report form contains fields for the first examination and two repeat examinations. The first examination at the allocated fasting interval will remain the basis of the primary outcome, regardless of subsequent emptying.
Anaesthesia and endoscopy
Anaesthetic management will follow the institution's clinical practice. During upper gastrointestinal endoscopy, the gastroenterologist will document the nature and quantity of residual gastric contents. Ultrasound and endoscopy times will be retained so that any interval between the two assessments is identifiable. The clinically indicated endoscopic procedure and routine recovery care will otherwise proceed according to usual practice.
Outcomes and interpretation
The first ultrasound assessment addresses the randomized three-hour versus four-hour comparison. Endoscopic observations occur after the ultrasound-guided decision to proceed and may therefore follow a longer interval in children requiring repeat scans. Agreement analyses will be interpreted in this procedural context. Direct endoscopic observations provide complementary information about residual contents; they do not independently establish the safety of the assigned fasting interval against rare pulmonary aspiration events.
Baskent University Ankara Hospital is the lead sponsor of 18 studies on the registry; 3 are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Twelve children will be assigned to a planned three-hour interval between yoghurt intake and the first gastric ultrasound assessment. Yoghurt may be consumed ad libitum up to 150 g, with no fixed or weight-based dose; actual intake will be recorded. Gastric ultrasound will be repeated at 10-minute intervals if the empty-stomach criterion is not met. Endoscopy will follow the ultrasound-guided decision to proceed with anaesthesia. The ultrasound and endoscopy assessors will be blinded to allocation.
Other: Three-hour fasting after yoghurt breakfast
Twelve children will be assigned to a planned four-hour interval between yoghurt intake and the first gastric ultrasound assessment. Yoghurt may be consumed ad libitum up to 150 g, with no fixed or weight-based dose; actual intake will be recorded. Gastric ultrasound will be repeated at 10-minute intervals if the empty-stomach criterion is not met. Endoscopy will follow the ultrasound-guided decision to proceed with anaesthesia. The ultrasound and endoscopy assessors will be blinded to allocation.
Other: Four-hour fasting after yoghurt breakfast
Ad libitum oral intake of yoghurt, capped at 150 g, followed by a planned three-hour fasting interval before the first gastric ultrasound examination. There is no predetermined fixed or weight-based dose. The quantity actually consumed and actual fasting interval will be recorded.
Ad libitum oral intake of yoghurt, capped at 150 g, followed by a planned four-hour fasting interval before the first gastric ultrasound examination. There is no predetermined fixed or weight-based dose. The quantity actually consumed and actual fasting interval will be recorded.
Proportion of children with an empty stomach on the first gastric ultrasound assessment
The primary comparison is between the randomized three-hour and four-hour fasting groups after yoghurt intake. Number and proportion of children with ultrasound-estimated gastric content volume below 1.5 mL/kg at the first examination after the allocated fasting interval. The estimate is calculated from antral cross-sectional area using GCV (mL/kg) = 0.0093 x CSA (mm2) - 0.96. The first examination will determine this outcome even if subsequent scans show emptying after additional waiting.
Time frame: At the first ultrasound assessment, 3 or 4 hours after yoghurt ingestion according to randomized allocation, on the procedure day.
Ultrasound-estimated gastric volume at the first assessment
Weight-indexed gastric content volume, expressed in mL/kg, estimated at the first ultrasound assessment using GCV = 0.0093 x antral CSA (mm2) - 0.96. Antral diameters are measured in triplicate in the right lateral decubitus position. Lower values indicate a smaller estimated residual volume.
Time frame: At the first ultrasound assessment, 3 or 4 hours after yoghurt ingestion, on the procedure day.
Proportion of children with an empty stomach on endoscopic assessment
Number and proportion of children classified as having an empty stomach on direct endoscopic inspection. An empty stomach is defined as no visible contents or only a non-aspirable trace; visible residual material beyond this trace is classified as non-empty. The nature and quantity of any residual contents will be documented. Endoscopy follows the ultrasound-guided decision to proceed, including additional waiting when required.
Time frame: During upper gastrointestinal endoscopy on the same procedure day, after ultrasound assessment.
Residual gastric content volume recorded during endoscopy
Quantity of gastric contents recorded during endoscopy, expressed in mL when measured by aspiration. The presence and character of residual contents will also be documented. A missing or unmeasured volume will not be assumed to be zero.
Time frame: During upper gastrointestinal endoscopy on the procedure day, after the ultrasound-guided decision to proceed.
Agreement between ultrasound and endoscopic empty or full classifications
Observed agreement and Cohen's kappa, where estimable, between categorical gastric ultrasound and endoscopic assessments. Assessment times and any repeat scans will be recorded. Interpretation will account for the interval between assessments and for the requirement to meet the ultrasound empty-stomach criterion before induction; the endoscopic sample may consequently contain predominantly ultrasound-empty observations.
Time frame: Paired ultrasound and endoscopic assessments during the same procedure-day visit.
Hunger rating at the first ultrasound assessment
Hunger recorded on the five-point scale in the case report form at the first ultrasound examination: 1 means not hungry at all and 5 means very hungry. Higher scores indicate greater hunger.
Time frame: At the first ultrasound assessment, 3 or 4 hours after yoghurt ingestion, on the procedure day.
Start is estimated for Oct 2026; primary completion for Oct 2026, 0 months later.
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Baskent University Ankara Hospital