Routine monitoring of gastric residual for prevention of necrotising enterocolitis in preterm infants.

Background: Routine monitoring of gastric residual in preterm infants on gavage feeds is a common practice used to guide initiation and advancement of feeds. It is believed that an increase in or an altered gastric residual may be predictive of necrotising enterocolitis (NEC). Withholding monitoring of gastric residual may take away the early indicator and thus may increase the risk of NEC. However, routine monitoring of gastric residual as a guide, in the absence of uniform standards, may lead to unnecessary delay in initiation and advancement of feeds and hence might result in a delay in establishing full enteral feeds. This in turn may increase the duration of total parenteral nutrition (TPN) and central venous line usage, increasing the risk of associated complications. Furthermore, delays in establishing full enteral feeds increase the risk of extrauterine growth restriction and neurodevelopmental impairment.

Objectives: • To assess the efficacy and safety of routine monitoring versus no monitoring of gastric residual in preterm infants • To assess the efficacy and safety of routine monitoring of gastric residual based on two different criteria for interrupting feeds or decreasing feed volume in preterm infants SEARCH METHODS: We conducted searches in Cochrane CENTRAL via CRS, Ovid MEDLINE, Embase and CINAHL in February 2022. We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials (RCTs), quasi- and cluster-RCTs.

Selection Criteria: We selected RCTs that compared routine monitoring versus no monitoring of gastric residual and trials that used two different criteria for gastric residual to interrupt feeds in preterm infants.

Data Collection And Analysis: Two authors independently assessed trial eligibility, risk of bias and extracted data. We analysed treatment effects in individual trials and reported risk ratio (RR) for dichotomous data, and mean difference (MD) for continuous data, with respective 95% confidence intervals (CI). We calculated the number needed to treat for an additional beneficial/harmful outcome (NNTB/NNTH) for dichotomous outcomes with significant results. We used GRADE to assess the certainty of evidence.

Main Results: We included five studies (423 infants) in this updated review. Routine monitoring versus no routine monitoring of gastric residual in preterm infants Four RCTs with 336 preterm infants met the inclusion criteria for this comparison. Three studies were performed in infants with birth weight of < 1500 g, while one study included infants with birth weight between 750 g and 2000 g. The trials were unmasked but were otherwise of good methodological quality. Routine monitoring of gastric residual:  - probably has little or no effect on the risk of NEC (RR 1.08, 95% CI 0.46 to 2.57; 334 participants, 4 studies; moderate-certainty evidence); - probably increases the time to establish full enteral feeds (MD 3.14 days, 95% CI 1.93 to 4.36; 334 participants, 4 studies; moderate-certainty evidence); - may increase the time to regain birth weight (MD 1.70 days, 95% CI 0.01 to 3.39; 80 participants, 1 study; low-certainty evidence);  - may increase the number of infants with feed interruption episodes (RR 2.21, 95% CI 1.53 to 3.20; NNTH 3, 95% CI 2 to 5; 191 participants, 3 studies; low-certainty evidence);  - probably increases the number of TPN days (MD 2.57 days, 95% CI 1.20 to 3.95; 334 participants, 4 studies; moderate-certainty evidence); - probably increases the risk of invasive infection (RR 1.50, 95% CI 1.02 to 2.19; NNTH 10, 95% CI 5 to 100; 334 participants, 4 studies; moderate-certainty evidence); - may result in little or no difference in all-cause mortality before hospital discharge (RR 2.14, 95% CI 0.77 to 5.97; 273 participants, 3 studies; low-certainty evidence). Quality and volume of gastric residual compared to quality of gastric residual alone for feed interruption in preterm infants One trial with 87 preterm infants met the inclusion criteria for this comparison. The trial included infants with 1500 g to 2000 g birth weight.  Using two different criteria of gastric residual for feed interruption: - may result in little or no difference in the incidence of NEC (RR 5.35, 95% CI 0.26 to 108.27; 87 participants; low-certainty evidence);  - may result in little or no difference in time to establish full enteral feeds (MD -0.10 days, 95% CI -0.91 to 0.71; 87 participants; low-certainty evidence); - may result in little or no difference in time to regain birth weight (MD 1.00 days, 95% CI -0.37 to 2.37; 87 participants; low-certainty evidence); - may result in little or no difference in number of TPN days (MD 0.80 days, 95% CI -0.78 to 2.38; 87 participants; low-certainty evidence); - may result in little or no difference in the risk of invasive infection (RR 5.35, 95% CI 0.26 to 108.27; 87 participants; low-certainty evidence); - may result in little or no difference in all-cause mortality before hospital discharge (RR 3.21, 95% CI 0.13 to 76.67; 87 participants; low-certainty evidence).  - we are uncertain about the effect of using two different criteria of gastric residual on the risk of feed interruption episodes (RR 3.21, 95% CI 0.13 to 76.67; 87 participants; very low-certainty evidence).

Authors' Conclusions: Moderate-certainty evidence suggests routine monitoring of gastric residual has little or no effect on the incidence of NEC. Moderate-certainty evidence suggests monitoring gastric residual probably increases the time to establish full enteral feeds, the number of TPN days and the risk of invasive infection. Low-certainty evidence suggests monitoring gastric residual may increase the time to regain birth weight and the number of feed interruption episodes, and may have little or no effect on all-cause mortality before hospital discharge. Further RCTs are warranted to assess the effect on long-term growth and neurodevelopmental outcomes.