Welcome to the GASTRIC Study Website

Parent Information

This study aims to identify the benefits of regularly measuring the amount of fluid in a child or baby’s stomach (GRV) to help decide if a child is ready to have the feed into their stomach. This fluid is measured by sucking it out via a tube already into the child’s stomach. This is a very common practice in intensive care units in the UK, but it is unclear if this practice is helpful.
One problem we know about is that it can delay the child getting the full amount of feed they need. Although there is research evidence from adults in intensive that not measuring it is safe, and they got more calories, we do not know whether not measuring GRV in babies and children could cause harm or be beneficial. Before a full trial can be undertaken, preparatory work is needed and this proposed study aims to do this.
The research is important because measuring GRV may prevent problems from overfeeding when the bowel cannot cope with milk and is not absorbing feeds. In children, the main problem is vomiting of the stomach contents, and breathing this fluid into the lungs. The main worry in babies under a month old, is a very serious infection of the bowel (necrotising enterocolitis). This nursing practice is heavily based on tradition and perceived risk, but benefits have not been proven and it may be harmful as feeds are often stopped, reducing the calories that babies and children receive.
If measuring GRV is not beneficial, then there will be savings in time and cost for staff and potential benefits from reaching nutritional dietary intakes sooner. Ensuring that babies and children have adequate feed is vital in intensive care, and not doing so slows recovery. Adequate energy supply to the organs, especially the brain and heart is needed in severe illness, and recovery requires enough calories to help heal damaged tissues. We know that inadequate nutrition is common in babies and children in intensive care units and measuring GRV may be contributing to this.
All children’s and baby’s intensive care units in the UK measure GRV routinely, unlike in other countries like France. Before changing practice in the UK, it is necessary to undertake a study to determine the benefits and safety of not measuring GRV.

Trial Summary

How will it the study be done?

We want to carry out research to assess whether we can feasibly do a trial across the UK. We will review the published literature and explore parents’ and healthcare professionals’ (nurses, doctors and dietitians) views around this practice (by surveys, interviews and a face to face meeting). We will also explore whether they would be prepared to participate in a future study and how they think we should approach such a study. From parents, we also want to know if this is important to them and whether they would be happy for their child to take part. We will develop and agree protocols for both measuring and not measuring GRV. We will use existing national children’s and neonatal intensive care databases to see if a trial is feasible. In the UK, children (0-17 years) and newborn babies are admitted to different types of intensive care units, with different staff and so we will conduct this study in parallel in both settings. Our research team (includes doctors, nurses, dietitians, social scientists and researchers from both PICU and NICU) is ideally placed to undertake this work. We will utilise the expertise of French intensive care teams who have already stopped measuring gastric residuals.

Aims and Objectives

The GASTRIC feasibility study answer the question: Is it feasible to conduct a study identifying the impact of not measuring gastric residual volume on clinical outcomes in mechanically ventilated infants and children receiving enteral feeding?

To achieve this our specific study objectives are to:

  1. Undertake a literature review to identify key outcome measures used for trials of enteral feeding in the PICU and NICU population
  2. To establish 'standard care practices' around enteral feeding and GRV measurement in all UK PICUs and NICUs (via an e-survey)
  3. To explore healthcare professionals (nurses, doctors and dietitians) views around GRV measurement, acceptability of not measuring GRV, alternative methods to assess feed tolerance, willingness to randomise to or comply with a future trial, barriers to recruitment, perceived training needs and inclusion and exclusion criteria
  4. To explore PICU and NICU parents and/or patients views around GRV measurement, acceptability of not measuring GRV, willingness to agree to a future trial, barriers to recruitment, patient (parent) centred outcomes and information needs for parents
  5. To determine and gain consensus on future trial issues including optimal trial design, primary and secondary outcome measures and inclusion and exclusion criteria.
  6. To determine trial feasibility (in both PICU and NICU) using routinely collected national clinical data sets (PICANet and NNRD)
  7. To agree (using a consensus process) a standard (control) arm (with routine GRV measurement) and an intervention arm (no routine GRV measurement) of a future trial.
  8. To amalgamate all the data generated and inform the aim of the feasibility study to determine whether a trial of no GRV measurement is feasible in UK PICUs and NICUs

Healthcare Professional Information

Underfeeding and inadequate nutrition remain constant concerns in neonatal (NICUs) and paediatric intensive care units (PICUs). An international study of 800 children in 31 PICUs showed only 37% of children received their prescribed energy intake, and that it took nearly 12 days to achieve 90% of their calorie target (4). On average, children in PICUs receive less than half of their predicted energy requirements (5,6). Achieving adequate nutrition in preterm infants is vital but equally challenging for different reasons. Whilst extremely preterm infants are routinely commenced on parenteral nutrition (PN) to meet their energy, carbohydrate, protein and lipid requirements, this comes with risks. PN requires invasive intravenous catheters and PN is the ideal medium for bacterial growth - the longer the PN duration, the higher the risk of developing severe infections (7,8). UK data shows that for babies born at 24 weeks, the median time taken to establish enteral feeding is 19 days (NNRD 2017). Delays in starting and establishing adequate nutrition via the enteral route are known to increase the risk of infectious complications and possibly death (9,10). Interventions to safely reduce the time to full enteral feeds therefore offer significant health and economic benefits and savings from reduced reliance on costly intravenous feeding. In addition to the impact on patients, this practice takes up considerable nursing time, which may be better spent on other patient and parent elated care tasks.

Inadequate energy delivery to critically ill infants and children has deleterious consequences. There is evidence that malnutrition is prevalent in mechanically ventilated children on admission to PICUs worldwide (11) and that this is linked to worse patient outcomes (12-14), and longer length of mechanical ventilation and intensive care stay (14-17). There is also evidence in preterm infants that neonatal nutritional status can affect outcomes; negative effects on brain development is an especially worrying consequence of inadequate nutrition (18-20). Therefore any practices which may be contributing to underfeeding and under nutrition warrant urgent investigation. The practice in question: A common nursing practice to assess enteral nutrition (EN) ‘tolerance’ is to measure gastric residual volume (GRV) frequently and routinely (21-24). GRV is known to be a significant factor in the decision to stop or withhold enteral nutrition (21, 24-26). Indeed, ‘high’ GRV levels often lead to withholding EN and this is a common barrier to delivering adequate amounts of EN in NICUs and PICUs (27,28).

Despite the prevalence of this practice, the evidence for GRV actually reflecting feed tolerance is poor, and GRV does not correlate directly to enteral feeding tolerance (29-31). GRV is frequently inaccurate due to position of the feeding tube in the stomach, patient position, feeding method, technique of aspiration and tube and syringe sizes used. What volume constitutes an ‘acceptable’ level of GRV also remains unknown. So, not only is GRV unreliable as a procedure, but it is also a time consuming, taking up valuable nursing time and resources (increasing costs) which may be best spent on other patient related tasks (32,33).

The practice of GRV measurement is widespread in PICUs and NICUs internationally, but with increasing evidence questioning the practice (in adults) it is now timely to examine this practice in critically ill neonates and children. The measurement of GRV features heavily in efforts to mitigate the perceived risk of pulmonary aspiration in mechanically ventilated patients (34), this risk remains unquantified (35). In adult intensive care trials, accepting a higher GRV (500ml compared to 200ml)(35) or not measuring GRV.



A mixed method study involving 5 linked work packages, running in two parallel arms, one in NICU and one in PICU over an 18-month time frame.


Please feel free to contact the GASTRIC study team by any of the means below:


00 44 (0) 117 32 86828


Medicines for Children Clinical Trials Unit
Clinical Trials Research Centre
University of Liverpool
Institute of Child Health
Alder Hey Children's NHS Foundation Trust
L12 2AP


Study team

The Gastric study team