Gastric EmptyingPROPEL-ECMONCT07779174
Prevalence and Measurement of Delayed Gastric Emptying in Patients Receiving Extracorporeal Membrane Oxygenation
An observational study of Gastric Emptying and Delayed Gastric Emptying, run by Guy's and St Thomas' NHS Foundation Trust at 1 site in United Kingdom.
Trial summary
The goal of this observational study is to learn whether the stomach takes longer to empty in patients on the intensive care unit who are receiving ECMO (a machine that temporarily takes over the role of the lungs and heart) compared to patients receiving support through a breathing machine (mechanical ventilation)… Read more about this study
- Who is it for?
- Ages 18 to 80 years
- Conditions the study is for
- Gastric Emptying, Delayed Gastric Emptying, Critical Illness
- What is being tested?
- Gastric (stomach) ultrasound measurement, 'Residual volume' measurement and Scintigraphy (standard research method)
- How many people
- 72 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- Sep 2026to Jun 2028
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Patients receiving mechanical ventilation (including those receiving ECMO) admitted to the Guy's \& St Thomas' Adult ICUs during the study period will be screened consecutively for eligibility against the inclusion / exclusion criteria. Eligibility screening will be done using the electronic healthcare record within 72 hours of admission to the participating ICU. All patients meeting all of the inclusion criteria and none of the exclusion criteria will be approached for consent and considered for recruitment if logistically feasible (i.e. if a trained staff member is available on site to undertake the gastric ultrasound/scintigraphy measurements). The total target sample size for this study is 72 patients (36 receiving ECMO; 36 not receiving ECMO).
Who may be able to join
- Within 72 hours of Guy's \& St Thomas' ICU admission
- Mechanically ventilated adults (≥18 years)
- Receiving enteral nutrition (liquid nutrition) via a gastric (nasogastric or orogastric) feeding tube
- Informed consent / advice for participation by consultee
- Availability of study investigator or other trained healthcare professional on site to complete gastric emptying (stomach emptying) measurements
- Within 72 hours of Guy's \& St Thomas' ICU admission
Show all 11Show fewer
- Mechanically ventilated adults (≥18 years)
- Receiving enteral nutrition (liquid nutrition) via a gastric (nasogastric or orogastric) feeding tube
- Informed consent / advice for participation by consultee
- Availability of study investigator or other trained healthcare professional on site to complete gastric emptying (stomach emptying) measurements
- Receiving either veno-venous or veno-arterial ECMO
Who cannot join
- Pregnancy
- History of gastroparesis (long-term slow stomach emptying)
- Current acute or long-term gastrointestinal pathology (stomach or bowel problem) that may influence gastric emptying (e.g. inflammatory bowel disease, coeliac disease, pancreatic exocrine insufficiency)
- Current contraindication to enteral nutrition (liquid nutrition) (e.g. clinical or radiological evidence of bowel obstruction, bowel ischaemia, ileus, upper gastrointestinal bleeding)
- Enteral nutrition (liquid nutrition) through a gastrostomy, jejunostomy or nasojejunal feeding tube
- Current or previous oesophageal, stomach or major small bowel surgery
Show all 10Show fewer
- Known anatomical abnormality of the stomach (e.g. hiatus hernia)
- Pericardial / abdominal drains or surgical wounds obstructing site of ultrasound scanning
- Nuclear medicine therapeutic administration, or diagnostic scintigraphy investigation in the previous 72 hours
- Unlikely to survive or withdrawal of life-sustaining treatment expected in the next 48 hours
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United Kingdom1 site
Guy's & St Thomas' NHS Foundation Trust
London
Rachel Fay, +44 (0) 207 188 7188 ext. 54426, gstt.RandD@nhs.net
Dr Brijesh Patel
About this study
Official title: A Prospective Observational Study Exploring the Prevalence and Measurement of Delayed Gastric Emptying in Critically Ill Adults Receiving Extracorporeal Membrane Oxygenation
- The goal of this observational study is to learn whether the stomach takes longer to empty in patients on the intensive care unit who are receiving ECMO (a machine that temporarily takes over the role of the lungs and heart) compared to patients receiving support through a breathing machine (mechanical ventilation) only. It will also find the best way to measure stomach emptying at the bedside.
- The main questions it aims to answer are:
- What is the prevalence of slow stomach emptying and other stomach or bowel problems in patients receiving ECMO, compared to patients receiving mechanical ventilation but not receiving ECMO? (Stage A)
- What is the best bedside method to measure stomach emptying in patients receiving ECMO? (Stage B)
- Stage A of the study will involve measuring stomach emptying in study participants within four days of ICU admission, using two bedside methods:
- 'Residual volumes' (removing liquid nutrition left in the stomach with a syringe, after this has been given through the participant's usual feeding tube)
- A stomach ultrasound scan The researchers will check for differences between patients receiving ECMO versus no ECMO, and how this relates to the nutrition patients receive and how well or unwell they become in ICU.
- In a smaller subgroup of patients receiving ECMO and participating in Stage B of the study, the researchers will also use scintigraphy. This is a standard research scan that tracks how the stomach empties by mixing a small, safe amount of radioactivity in the participant's usual liquid nutrition. The researchers will compare stomach emptying results from 'residual volumes' and stomach ultrasound with scintigraphy.
Read the detailed description
- When patients are very unwell and admitted to the intensive care unit (ICU), they may need support for their breathing through a breathing machine (known as mechanical ventilation). Patients with severe heart or lung illness may also require life support using 'extracorporeal membrane oxygenation' (ECMO), a machine that takes over the role of the lungs and heart to keep them alive.
- These patients are primarily given nutrition in the liquid form, through a tube placed into their stomach via the nose or mouth ('gastric tube'). While gastric tube feeding is commonly used for patients requiring mechanical ventilation and ECMO, current research shows that these patients often do not receive enough nutrition through their gastric tubes.
- Slow stomach emptying (often referred to as 'delayed gastric emptying') and other stomach or bowel problems ('gastrointestinal' complications) are thought to be common reasons for not receiving enough nutrition in patients receiving ECMO. Several factors may put these patients at higher risk of delayed gastric emptying, including their high level of illness, complex sedation, unstable blood pressure, and poor blood flow to the gut. Despite this, there is limited research on delayed gastric emptying in patients receiving ECMO.
- Not receiving enough nutrition has been associated with longer hospital stays and higher risk of death in patients receiving ECMO, and poorer physical recovery from ICU. Health professionals need to know if the stomach is emptying adequately to ensure that patients receive the nutrition they need.
- A common way to measure how much liquid nutrition is in a patients' stomach is by removing liquid nutrition left in the stomach with a syringe through the gastric tube ('residual volumes'). While this is a quick and inexpensive method that can be used on the bedside, it has been shown to be imprecise in identifying delayed gastric emptying.
- Another method is stomach ultrasound, a painless scan which is commonly available and has shown promising results in healthy individuals and general ICU patients. However, this has not yet been tested in patients receiving ECMO.
- The standard research method for measuring how fast or slow the stomach empties is called 'scintigraphy'. Scintigraphy uses a small, safe amount of radioactivity mixed in the patient's liquid nutrition and a special camera to scan the stomach. However, this is more expensive, labour-intensive and requires portable equipment not available in most hospitals. Therefore, it is only used for research purposes in ICU.
- Without a suitable bedside method to measure stomach emptying, there is a risk that delayed gastric emptying may not be properly managed in clinical practice. This may lead to delays in treatment, such as giving medications or changing feeding strategies, or unnecessary interruptions of gastric tube feeding resulting in poor nutritional intake.
- This study has two stages:
- Stage A aims to observe whether the stomach takes longer to empty in patients receiving ECMO compared to patients receiving mechanical ventilation but not receiving ECMO, and whether this relates to the nutrition patients receive and how well or unwell they become in ICU.
- Stage B aims to identify the most appropriate method ('residual volumes' or stomach ultrasound) for measuring stomach emptying in ICU for this patient population.
- Stage A will aim to recruit 72 participants in total (36 receiving ECMO; 36 not receiving ECMO). Stomach emptying will be measured within four days of ICU admission using 'residual volumes' and stomach ultrasound, and differences between patients receiving ECMO versus no ECMO will be assessed. The study will also check whether delayed gastric emptying and any other gastrointestinal complications experienced by patients relate to how much nutrition patients receive during the first 14 days of their ICU stay, how well-nourished they are on ICU admission and discharge (nutritional status), and how well or unwell they become while in ICU (clinical outcomes).
- In stage B, scintigraphy will also be undertaken in a subgroup of 27 patients receiving ECMO from stage A to measure the rate of stomach emptying (how fast or slow the stomach empties) and stomach retention (the amount of liquid nutrition remaining in the stomach), and results from 'residual volumes' and stomach ultrasound will be compared with this.
- The investigators believe that findings from this study may help to better measure stomach emptying in clinical practice, inform timely management of delayed gastric emptying and in turn improve the nutrition patients receive and their clinical recovery.
- Conditions
- Gastric Emptying, Delayed Gastric Emptying, Critical Illness, ExtraCorporeal Membrane Oxygenation (ECMO)
- Being tested
- Gastric (stomach) ultrasound measurement, 'Residual volume' measurement, Scintigraphy (standard research method)
- Keywords
- Gastric emptying, Critical Illness, Extracorporeal Membrane Oxygenation, Delayed gastric emptying, Nutrition
- Medical subject headings
- Gastroparesis, Critical Illness
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Gastric (stomach) ultrasound measurementOther
Gastric ultrasound will be performed within 4 days of admission to the participating ICU, for all 72 participants included in Stage A of the study. An ultrasound machine will be gently pressed against the participant's abdomen to measure how much liquid nutrition is left in their stomach over time.
To do this, 100ml of liquid nutrition will be given through their gastric tube at the start of the scan. Five measurements will be taken in total, one at the start (baseline) and then one every hour for a total of four hours. A special measurement from the ultrasound scan ('antral cross-sectional area') will be used to calculate the amount of liquid in the stomach. In preparation for the scan, the participant's regular liquid nutrition will be paused for at least 4 hours.
'Residual volume' measurementOther
'Residual volumes' are measured every four hours by nurses in ICU as part of routine care. A 'residual volume' measurement will be done for all 72 participants included in Stage A of the study immediately before the ultrasound scan. The measurements taken from each participant during the first 7 days of their ICU stay (including the 24 hours before gastric ultrasound measurements) will also be recorded from the electronic healthcare records.
Scintigraphy (standard research method)Other
In addition to gastric ultrasound and residual volumes, scintigraphy will also be carried out for a subgroup of 27 patients receiving ECMO (i.e. those participating in stage B) to measure stomach emptying and stomach retention.
The liquid nutrition given at the start of the scan will be mixed with a small and safe amount of radioactivity by a specialist Nuclear Medicine Physicist. A special camera (portable gamma camera) will then be placed over the participant's stomach, which will take images over four hours (one at baseline, then one every 15 minutes for the first hour, followed by every 30 minutes for the next three hours). Each scan will last up to 5 minutes. A Nuclear Medicine Physicist will then analyse the images. Patients who are suitable to have scintigraphy will be identified through discussion with their treating ICU consultant.
| Study group | Role | What they receive |
|---|---|---|
| Non-ECMO group | Participants who are in ICU and receiving mechanical ventilation, but not receiving ECMO. Receives: Other: Gastric (stomach) ultrasound measurement; Other: 'Residual volume' measurement | |
| ECMO group | Participants who are in ICU and receiving both mechanical ventilation and ECMO. Receives: Other: Gastric (stomach) ultrasound measurement; Other: 'Residual volume' measurement; Other: Scintigraphy (standard research method) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Prevalence of delayed gastric emptying (number of participants experiencing delayed gastric emptying) using stomach ultrasound in participants receiving ECMO compared to those receiving mechanical ventilation but not receiving ECMO (STAGE A).
The prevalence of delayed gastric emptying will be determined using stomach ultrasound ('antral cross-sectional area') in all 72 participants of Stage A (including ECMO and non-ECMO groups).
The assessment of delayed gastric emptying prevalence will involve five stomach ultrasound measurements undertaken at pre-defined timepoints over a 4-hour duration. This will include calculation of percentage gastric retention (% of liquid nutrition volume remaining in stomach relative to that originally administered), which will be based upon measurements of 'antral cross-sectional area' (cm2) and subsequent calculation of stomach volume (millilitres, mL) (see interventions section).
The definition of delayed gastric emptying prevalence using ultrasound will be determined based upon the optimum association with gastric emptying measured via scintigraphy, as identified in Stage B.
Measured: Assessment of delayed gastric emptying prevalence using ultrasound will be undertaken once for each participant, and this will be done within the first 4 days of admission to the participating ICU.
Prevalence of delayed gastric emptying (number of participants experiencing delayed gastric emptying) using 'residual volumes' in participants receiving ECMO compared to those receiving mechanical ventilation but not receiving ECMO (STAGE A).
The prevalence of delayed gastric emptying will be determined for all 72 participants of Stage A (including ECMO and non-ECMO groups) using 'residual volumes' measured in millilitres (mL) (see interventions section). Delayed gastric emptying will be defined as any 'residual volume' measurement of more than 400 mL (current local institutional protocol threshold).
Measured: Assessment of delayed gastric emptying prevalence using 'residual volumes' will be undertaken during the 24 hours preceding stomach ultrasound assessment (within the first 3 days admission to the ICU), based on 4-hourly 'residual volume' measurements.
Association of stomach ultrasound ('antral cross-sectional area') and 'residual volumes' for measuring stomach emptying compared with the standard research method of scintigraphy in participants receiving ECMO (STAGE B).
Stomach emptying will be measured using scintigraphy in a subgroup of 27 participants receiving ECMO from Stage A. This will be determined based upon a combination of percentage (%) stomach retention calculated at pre-defined timepoints over a 4-hour duration (see interventions section), as well as stomach emptying rate (i.e. time [minutes] taken for half of the infused liquid nutrition to empty).
These parameters will be compared with the those from stomach ultrasound and 'residual volume' measurements to determine the bedside clinical method with the optimum association.
Measured: Assessment of stomach emptying using scintigraphy will be undertaken once for each participant, and this will be done within the first 4 days of admission to the participating ICU.
Secondary outcomes (10)
Prevalence of other gastrointestinal complications (number of participants experiencing other gastrointestinal complications)
Presence/absence of any of the following (as documented on electronic electronic healthcare records):
- Vomiting
- Bowel ischaemia (poor blood flow to the gut), identified via clinically indicated abdominal imaging
- Upper-gastrointestinal bleeding (bleeding from the stomach or upper part of small bowel), identified via clinically indicated endoscopy
- Diarrhoea, defined as:
- For patients without a bowel management system: two consecutive days of ≥3 loose stools (type 6 or 7 on the Bristol Stool Form Scale) in the absence of laxatives;
- For patients with a bowel management system: output of >250ml in the absence of laxatives.
- Constipation (defined to align with Rome IV Criteria for functional constipation), to include two of the following:
- infrequent stools (bowels not opening for ≥3 consecutive days);
- hard stools (classified as type 1 or 2 on the Bristol Stool Form Scale);
- the requirement for laxative up-titration within one day of one of the first two symptoms
Measured: Daily, for the first 7 days of admission to the participating ICU (or until ECMO is discontinued for participants in the ECMO group / initiated for participants in the non-ECMO group, whichever occurs first).
Nutritional status
Nutritional status (how well-nourished the participant is) will be measured by a Critical Care Dietitian using standardised assessment methods (i.e. Subjective Global Assessment).
The association between delayed gastric emptying and other gastrointestinal complications with nutritional status will be explored.
Measured: Baseline (i.e. once within the first 72 hours of admission to the participating ICU), and ICU discharge (i.e once within +- 72 hours of discharge from the participating ICU).
Nutritional delivery (mean percentage of energy and protein targets achieved)
Nutritional delivery (the percentage of liquid nutrition the participant has received relative to their estimated energy and protein targets) will be measured daily by Critical Care Dietitians as part of routine care. The mean percentage nutritional delivery over the first 0-3, 4-7, and 8-14 days of ICU admission will be calculated.
The association between delayed gastric emptying and other gastrointestinal complications with nutritional delivery will be explored.
Measured: Daily during the first 14 days of admission to the participating ICU (or until discharge from ICU/transfer to another institution/death/feeding tube removal/intentional reduction in liquid nutrition to support oral food intake; whichever occurs first).
Nutritional adequacy
Achievement of nutritional adequacy will be determined at the following timepoints, with adequacy defined according to current international critical care nutrition guidelines:
- Days 0-3 of ICU admission (adequacy defined as 0-70% of mean energy and protein targets)
- Days 4-7 of ICU admission (adequacy defined as 70-100% of mean energy and protein targets)
- Days 8-14 days of ICU admission (adequacy defined as 80-110% of energy and protein targets)
The association between delayed gastric emptying and other gastrointestinal complications with nutritional adequacy will be explored.
Measured: Daily during the first 14 days of admission to the participating ICU (or until discharge from ICU/transfer to another institution/death/feeding tube removal/intentional reduction in liquid nutrition to support oral food intake; whichever occurs first).
ICU mortality
Data on whether participants deceased during their ICU stay will be obtained from the electronic healthcare record.
The association between delayed gastric emptying and ICU mortality will be explored.
Measured: From day of recruitment until day of discharge from the participating ICU or death (whichever occurs first), assessed up to 60 days.
Hospital mortality
Data on whether participants deceased during their hospital stay will be obtained from the electronic healthcare record.
The association between delayed gastric emptying and hospital mortality will be explored.
Measured: From day of recruitment through study completion (i.e. until day of discharge from institution or death, whichever occurs first), assessed up to 60 days.
Duration of ICU stay
Data on the duration of the participants' ICU stay (measured in days) will be obtained from the electronic healthcare record.
The association between delayed gastric emptying and duration of ICU stay will be explored.
Measured: From day of admission to the participating ICU until day of discharge from the participating ICU or death (whichever occurs first), assessed up to 60 days.
Duration of hospital stay
Data on the duration of the participants' hospital stay (measured in days) will be obtained from the electronic healthcare record.
The association between delayed gastric emptying and duration of hospital stay will be explored.
Measured: From day of admission to the participating institution through study completion (i.e. until day of discharge from the institution or death, whichever occurs first), assessed up to 60 days.
Duration of ECMO support
Data on the duration of ECMO support (measured in days) will be obtained from the electronic healthcare record for participants receiving ECMO.
The association between delayed gastric emptying and duration of ECMO support will be explored.
Measured: From day of ECMO initiation until day of ECMO decannulation (or day of discharge from the participating ICU or death, whichever occurs first), assessed up to 60 days.
Duration of mechanical ventilation
Data on the duration of mechanical ventilation (measured in days) will be obtained from the electronic healthcare record.
The association between delayed gastric emptying and duration of mechanical ventilation will be explored.
Measured: From day of mechanical ventilation initiation until day of mechanical ventilation cessation (or day of discharge from the participating ICU or death, whichever occurs first), assessed up to 60 days.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Aug 2026
- Study startSep 2026 (estimated)
- Primary completionMay 2028 (estimated)
- Study completionJun 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Gastric EmptyingStudies of the same condition, open and under way.
- More trials run by Guy's and St Thomas' NHS Foundation TrustThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 72 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Guy's and St Thomas' NHS Foundation Trust
- Sponsor type
- University, hospital or other
- Collaborators
- King's College London
- Responsible party
- Sponsor
- Investigators
- Professor Kevin Whelan, PhD, Study director, King's College London
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07779174
- Sponsor's protocol ID
- 344452
- Other IDs
- NIHR305256
- Acronym
- PROPEL-ECMO
- Status last verified
- Aug 2026
- First submitted
- 13 Jul 2026
- Last updated
- 21 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 21 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Prospective Observational Study Exploring the Prevalence and Measurement of Delayed Gastric Emptying in Critically Ill Adults Receiving Extracorporeal Membrane Oxygenation
- ClinicalTrials.gov ID
- NCT07779174
- Acronym / sponsor ID
- PROPEL-ECMO / 344452
- Conditions
- Gastric Emptying, Delayed Gastric Emptying, Critical Illness, ExtraCorporeal Membrane Oxygenation (ECMO)
- Keywords
- Gastric emptying, Critical Illness, Extracorporeal Membrane Oxygenation, Delayed gastric emptying, Nutrition
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 72 participants (estimated)
- Lead sponsor
- Guy's and St Thomas' NHS Foundation TrustUniversity, hospital or other
- Collaborators
- King's College London
- Study start
- Sep 2026 (estimated)
- Primary completion
- May 2028 (estimated)
- Study completion
- Jun 2028 (estimated)
- First posted
- 21 Aug 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
- The goal of this observational study is to learn whether the stomach takes longer to empty in patients on the intensive care unit who are receiving ECMO (a machine that temporarily takes over the role of the lungs and heart) compared to patients receiving support through a breathing machine (mechanical ventilation) only. It will also find the best way to measure stomach emptying at the bedside.
- The main questions it aims to answer are:
- What is the prevalence of slow stomach emptying and other stomach or bowel problems in patients receiving ECMO, compared to patients receiving mechanical ventilation but not receiving ECMO? (Stage A)
- What is the best bedside method to measure stomach emptying in patients receiving ECMO? (Stage B)
- Stage A of the study will involve measuring stomach emptying in study participants within four days of ICU admission, using two bedside methods:
- 'Residual volumes' (removing liquid nutrition left in the stomach with a syringe, after this has been given through the participant's usual feeding tube)
- A stomach ultrasound scan The researchers will check for differences between patients receiving ECMO versus no ECMO, and how this relates to the nutrition patients receive and how well or unwell they become in ICU.
- In a smaller subgroup of patients receiving ECMO and participating in Stage B of the study, the researchers will also use scintigraphy. This is a standard research scan that tracks how the stomach empties by mixing a small, safe amount of radioactivity in the participant's usual liquid nutrition. The researchers will compare stomach emptying results from 'residual volumes' and stomach ultrasound with scintigraphy.
Detailed description
- When patients are very unwell and admitted to the intensive care unit (ICU), they may need support for their breathing through a breathing machine (known as mechanical ventilation). Patients with severe heart or lung illness may also require life support using 'extracorporeal membrane oxygenation' (ECMO), a machine that takes over the role of the lungs and heart to keep them alive.
- These patients are primarily given nutrition in the liquid form, through a tube placed into their stomach via the nose or mouth ('gastric tube'). While gastric tube feeding is commonly used for patients requiring mechanical ventilation and ECMO, current research shows that these patients often do not receive enough nutrition through their gastric tubes.
- Slow stomach emptying (often referred to as 'delayed gastric emptying') and other stomach or bowel problems ('gastrointestinal' complications) are thought to be common reasons for not receiving enough nutrition in patients receiving ECMO. Several factors may put these patients at higher risk of delayed gastric emptying, including their high level of illness, complex sedation, unstable blood pressure, and poor blood flow to the gut. Despite this, there is limited research on delayed gastric emptying in patients receiving ECMO.
- Not receiving enough nutrition has been associated with longer hospital stays and higher risk of death in patients receiving ECMO, and poorer physical recovery from ICU. Health professionals need to know if the stomach is emptying adequately to ensure that patients receive the nutrition they need.
- A common way to measure how much liquid nutrition is in a patients' stomach is by removing liquid nutrition left in the stomach with a syringe through the gastric tube ('residual volumes'). While this is a quick and inexpensive method that can be used on the bedside, it has been shown to be imprecise in identifying delayed gastric emptying.
- Another method is stomach ultrasound, a painless scan which is commonly available and has shown promising results in healthy individuals and general ICU patients. However, this has not yet been tested in patients receiving ECMO.
- The standard research method for measuring how fast or slow the stomach empties is called 'scintigraphy'. Scintigraphy uses a small, safe amount of radioactivity mixed in the patient's liquid nutrition and a special camera to scan the stomach. However, this is more expensive, labour-intensive and requires portable equipment not available in most hospitals. Therefore, it is only used for research purposes in ICU.
- Without a suitable bedside method to measure stomach emptying, there is a risk that delayed gastric emptying may not be properly managed in clinical practice. This may lead to delays in treatment, such as giving medications or changing feeding strategies, or unnecessary interruptions of gastric tube feeding resulting in poor nutritional intake.
- This study has two stages:
- Stage A aims to observe whether the stomach takes longer to empty in patients receiving ECMO compared to patients receiving mechanical ventilation but not receiving ECMO, and whether this relates to the nutrition patients receive and how well or unwell they become in ICU.
- Stage B aims to identify the most appropriate method ('residual volumes' or stomach ultrasound) for measuring stomach emptying in ICU for this patient population.
- Stage A will aim to recruit 72 participants in total (36 receiving ECMO; 36 not receiving ECMO). Stomach emptying will be measured within four days of ICU admission using 'residual volumes' and stomach ultrasound, and differences between patients receiving ECMO versus no ECMO will be assessed. The study will also check whether delayed gastric emptying and any other gastrointestinal complications experienced by patients relate to how much nutrition patients receive during the first 14 days of their ICU stay, how well-nourished they are on ICU admission and discharge (nutritional status), and how well or unwell they become while in ICU (clinical outcomes).
- In stage B, scintigraphy will also be undertaken in a subgroup of 27 patients receiving ECMO from stage A to measure the rate of stomach emptying (how fast or slow the stomach empties) and stomach retention (the amount of liquid nutrition remaining in the stomach), and results from 'residual volumes' and stomach ultrasound will be compared with this.
- The investigators believe that findings from this study may help to better measure stomach emptying in clinical practice, inform timely management of delayed gastric emptying and in turn improve the nutrition patients receive and their clinical recovery.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Non-ECMO group | – | Other: Gastric (stomach) ultrasound measurement, Other: 'Residual volume' measurementParticipants who are in ICU and receiving mechanical ventilation, but not receiving ECMO. |
| ECMO group | – | Other: Gastric (stomach) ultrasound measurement, Other: 'Residual volume' measurement, Other: Scintigraphy (standard research method)Participants who are in ICU and receiving both mechanical ventilation and ECMO. |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Patients receiving mechanical ventilation (including those receiving ECMO) admitted to the Guy's \& St Thomas' Adult ICUs during the study period will be screened consecutively for eligibility against the inclusion / exclusion criteria. Eligibility screening will be done using the electronic healthcare record within 72 hours of admission to the participating ICU. All patients meeting all of the inclusion criteria and none of the exclusion criteria will be approached for consent and considered for recruitment if logistically feasible (i.e. if a trained staff member is available on site to undertake the gastric ultrasound/scintigraphy measurements). The total target sample size for this study is 72 patients (36 receiving ECMO; 36 not receiving ECMO).
Key inclusion criteria (11 listed)
Key exclusion criteria (10 listed)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Gastric (stomach) ultrasound measurementGastric ultrasound will be performed within 4 days of admission to the participating ICU, for all 72 participants included in Stage A of the study. An ultrasound machine will be gently pressed against the participant's abdomen to measure how much liquid nutrition is left in their stomach over time. To do this, 100ml of liquid nutrition will be given through their gastric tube at the start of the scan. Five measurements will be taken in total, one at the start (baseline) and then one every hour for a total of four hours. A special measurement from the ultrasound scan ('antral cross-sectional area') will be used to calculate the amount of liquid in the stomach. In preparation for the scan, the participant's regular liquid nutrition will be paused for at least 4 hours. | Other | ECMO group, Non-ECMO group |
| 'Residual volume' measurement'Residual volumes' are measured every four hours by nurses in ICU as part of routine care. A 'residual volume' measurement will be done for all 72 participants included in Stage A of the study immediately before the ultrasound scan. The measurements taken from each participant during the first 7 days of their ICU stay (including the 24 hours before gastric ultrasound measurements) will also be recorded from the electronic healthcare records. | Other | ECMO group, Non-ECMO group |
| Scintigraphy (standard research method)In addition to gastric ultrasound and residual volumes, scintigraphy will also be carried out for a subgroup of 27 patients receiving ECMO (i.e. those participating in stage B) to measure stomach emptying and stomach retention. The liquid nutrition given at the start of the scan will be mixed with a small and safe amount of radioactivity by a specialist Nuclear Medicine Physicist. A special camera (portable gamma camera) will then be placed over the participant's stomach, which will take images over four hours (one at baseline, then one every 15 minutes for the first hour, followed by every 30 minutes for the next three hours). Each scan will last up to 5 minutes. A Nuclear Medicine Physicist will then analyse the images. Patients who are suitable to have scintigraphy will be identified through discussion with their treating ICU consultant. | Other | ECMO group |
Primary outcome
Prevalence of delayed gastric emptying (number of participants experiencing delayed gastric emptying) using stomach ultrasound in participants receiving ECMO compared to those receiving mechanical ventilation but not receiving ECMO (STAGE A).
Time frame: Assessment of delayed gastric emptying prevalence using ultrasound will be undertaken once for each participant, and this will be done within the first 4 days of admission to the participating ICU.
The prevalence of delayed gastric emptying will be determined using stomach ultrasound ('antral cross-sectional area') in all 72 participants of Stage A (including ECMO and non-ECMO groups). The assessment of delayed gastric emptying prevalence will involve five stomach ultrasound measurements undertaken at pre-defined timepoints over a 4-hour duration. This will include calculation of percentage gastric retention (% of liquid nutrition volume remaining in stomach relative to that originally administered), which will be based upon measurements of 'antral cross-sectional area' (cm2) and subsequent calculation of stomach volume (millilitres, mL) (see interventions section). The definition of delayed gastric emptying prevalence using ultrasound will be determined based upon the optimum association with gastric emptying measured via scintigraphy, as identified in Stage B.
Prevalence of delayed gastric emptying (number of participants experiencing delayed gastric emptying) using 'residual volumes' in participants receiving ECMO compared to those receiving mechanical ventilation but not receiving ECMO (STAGE A).
Time frame: Assessment of delayed gastric emptying prevalence using 'residual volumes' will be undertaken during the 24 hours preceding stomach ultrasound assessment (within the first 3 days admission to the ICU), based on 4-hourly 'residual volume' measurements.
The prevalence of delayed gastric emptying will be determined for all 72 participants of Stage A (including ECMO and non-ECMO groups) using 'residual volumes' measured in millilitres (mL) (see interventions section). Delayed gastric emptying will be defined as any 'residual volume' measurement of more than 400 mL (current local institutional protocol threshold).
Association of stomach ultrasound ('antral cross-sectional area') and 'residual volumes' for measuring stomach emptying compared with the standard research method of scintigraphy in participants receiving ECMO (STAGE B).
Time frame: Assessment of stomach emptying using scintigraphy will be undertaken once for each participant, and this will be done within the first 4 days of admission to the participating ICU.
Stomach emptying will be measured using scintigraphy in a subgroup of 27 participants receiving ECMO from Stage A. This will be determined based upon a combination of percentage (%) stomach retention calculated at pre-defined timepoints over a 4-hour duration (see interventions section), as well as stomach emptying rate (i.e. time [minutes] taken for half of the infused liquid nutrition to empty). These parameters will be compared with the those from stomach ultrasound and 'residual volume' measurements to determine the bedside clinical method with the optimum association.
10 secondary outcomes
Prevalence of other gastrointestinal complications (number of participants experiencing other gastrointestinal complications)
Time frame: Daily, for the first 7 days of admission to the participating ICU (or until ECMO is discontinued for participants in the ECMO group / initiated for participants in the non-ECMO group, whichever occurs first).
Nutritional status
Time frame: Baseline (i.e. once within the first 72 hours of admission to the participating ICU), and ICU discharge (i.e once within +- 72 hours of discharge from the participating ICU).
Nutritional delivery (mean percentage of energy and protein targets achieved)
Time frame: Daily during the first 14 days of admission to the participating ICU (or until discharge from ICU/transfer to another institution/death/feeding tube removal/intentional reduction in liquid nutrition to support oral food intake; whichever occurs first).
Nutritional adequacy
Time frame: Daily during the first 14 days of admission to the participating ICU (or until discharge from ICU/transfer to another institution/death/feeding tube removal/intentional reduction in liquid nutrition to support oral food intake; whichever occurs first).
ICU mortality
Time frame: From day of recruitment until day of discharge from the participating ICU or death (whichever occurs first), assessed up to 60 days.
Hospital mortality
Time frame: From day of recruitment through study completion (i.e. until day of discharge from institution or death, whichever occurs first), assessed up to 60 days.
Duration of ICU stay
Time frame: From day of admission to the participating ICU until day of discharge from the participating ICU or death (whichever occurs first), assessed up to 60 days.
Duration of hospital stay
Time frame: From day of admission to the participating institution through study completion (i.e. until day of discharge from the institution or death, whichever occurs first), assessed up to 60 days.
Duration of ECMO support
Time frame: From day of ECMO initiation until day of ECMO decannulation (or day of discharge from the participating ICU or death, whichever occurs first), assessed up to 60 days.
Duration of mechanical ventilation
Time frame: From day of mechanical ventilation initiation until day of mechanical ventilation cessation (or day of discharge from the participating ICU or death, whichever occurs first), assessed up to 60 days.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 21 Aug 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Professor Kevin Whelan, PhD study director
King's College London
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Gastric Emptying and Delayed Gastric Emptying, run by Guy's and St Thomas' NHS Foundation Trust at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 11 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 21 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Terpsichori Karpasiti (+44 (0) 207 848 4552, terpsichori.karpasiti@kcl.ac.uk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Prevalence of delayed gastric emptying (number of participants experiencing delayed gastric emptying) using stomach ultrasound in participants receiving ECMO compared to those receiving mechanical ventilation but not receiving ECMO (STAGE A). (time frame: Assessment of delayed gastric emptying prevalence using ultrasound will be undertaken once for each participant, and this will be done within the first 4 days of admission to the participating ICU.). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 21 Aug 2026.