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:
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: