* 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.
* 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 Type
OBSERVATIONAL
Enrollment
72
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 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.
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.
Guy's & St Thomas' NHS Foundation Trust
London, United Kingdom
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.
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.
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).
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.
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.
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.
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: 1. 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; 2. 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: 1. infrequent stools (bowels not opening for ≥3 consecutive days); 2. hard stools (classified as type 1 or 2 on the Bristol Stool Form Scale); 3. the requirement for laxative up-titration within one day of one of the first two symptoms
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
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.
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)
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.
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).
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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.
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
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.
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
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.
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
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.
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
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.
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
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.
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
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.
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.