Routine monitoring of stomach aspirates for prevention of necrotising enterocolitis in preterm infants

Review question
Does routine monitoring of stomach aspirates in preterm infants prevent necrotising enterocolitis?

Background
Monitoring of stomach aspirates to diagnose feed intolerance and necrotising enterocolitis is a common practice in preterm infants who are on tube feeds. No adequate evidence supports routine monitoring of stomach aspirates as a guide to initiating and increasing feeds in otherwise healthy preterm infants. Withholding monitoring of stomach aspirates may take away the early indicator and thus may increase the risk of necrotising enterocolitis. However, routine monitoring of stomach aspirates as a guide, in the absence of uniform standards, may lead to unnecessary delay in initiation and advancement of feeds and delay in reaching full feeds. This in turn may increase the duration of parenteral nutrition and central line usage, thus increasing their complications. Delay in achieving full feeds increases the risk of growth restriction and neurodevelopmental impairment. We have looked for evidence from clinical trials that assessed whether routine monitoring of stomach aspirates is beneficial or harmful in preterm infants.

Study characteristics
The literature searches are up-to-date as of 19 February 2018. We found two small randomised controlled trials with a total of 141 preterm infant participants that compared routine monitoring versus no monitoring of stomach aspirates in preterm infants. We found one trial for the comparison of using two different criteria of aspirates to interrupt feeds while monitoring stomach aspirates in preterm infants.

Key results
There is uncertainty as to whether routine monitoring of stomach aspirates reduces necrotising enterocolitis because trial results are imprecise. Preterm infants on routine monitoring of stomach aspirates may reach full feeds later, regain birth weight later, require longer duration of parenteral nutrition, and may be at increased risk of feed interruption episodes.

There is uncertainty as to whether using two different criteria of gastric residual to interrupt feeds has effect on important outcomes in preterm infants.

Conclusions
There is uncertainty as to whether routine monitoring of stomach aspirates has any benefits. Routine monitoring may increase the number of feed interruption episodes and the time taken to reach full feeds.

Authors' conclusions: 

Review authors found insufficient evidence as to whether routine monitoring of gastric residual reduces the incidence of necrotising enterocolitis because trial results are imprecise. Low-quality evidence suggests that routine monitoring of gastric residual increases the risk of feed interruption episodes, increases the time taken to reach full enteral feeds and to regain birth weight, and increases the number of total parenteral nutrition (TPN) days.

Available data are insufficient to comment on other major outcomes such as incidence of invasive infection, parenteral nutrition-associated liver disease, mortality before discharge, extrauterine growth restriction at discharge, number of CVL days, and duration of hospital stay. Further randomised controlled trials are warranted to provide more precise estimates of the effects of routine monitoring of gastric residual on important outcomes, especially necrotising enterocolitis, in preterm infants.

Read the full abstract...
Background: 

Routine monitoring of gastric residual in preterm infants on gavage feeds is a common practice that is used to guide initiation and advancement of feeds. Some literature suggests that an increase in/or an altered gastric residual may be predictive of necrotising enterocolitis. Withholding monitoring of gastric residual may take away the early indicator and thus may increase the risk of necrotising enterocolitis. 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 delay in reaching full enteral feeds. This in turn may increase the duration of parenteral nutrition and central venous line usage, increasing their complications. Delay in achieving full enteral feeds increases the risk of extrauterine growth restriction and neurodevelopmental impairment.

Objectives: 

• To assess the efficacy and safety of routine monitoring of gastric residual 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

We planned to undertake subgroup analysis based on gestational age ( 27 weeks, 28 weeks to 31 weeks, ≥ 32 weeks), birth weight (< 1000 g, 1000 g to 1499 g, ≥ 1500 g), small for gestational age versus appropriate for gestational age infants (classified using birth weight relative to the reference population), type of feed the infant is receiving (human milk or formula milk), and frequency of monitoring of gastric residual (before every feed, before every third feed, etc.) (see "Subgroup analysis and investigation of heterogeneity").

Search strategy: 

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 1), MEDLINE via PubMed (1966 to 19 February 2018), Embase (1980 to 19 February 2018), and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to 19 February 2018). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

Selection criteria: 

We selected randomised and quasi-randomised controlled trials that compared routine monitoring of gastric residual versus no monitoring or two different criteria of gastric residual to interrupt feeds in preterm infants.

Data collection and analysis: 

Two review authors assessed trial eligibility and risk of bias and independently extracted data. We analysed treatment effects in individual trials and reported the risk ratio and the risk difference for dichotomous data, and the mean difference for continuous data, with respective 95% confidence intervals. We used the GRADE approach to assess the quality of evidence.

Main results: 

Two randomised controlled trials with a total of 141 preterm infants met the inclusion criteria for the comparison of routine monitoring versus no monitoring of gastric residual in preterm infants. Both trials were done in infants with birth weight < 1500 g.

Routine monitoring of gastric residual may have little or no effect on the incidence of necrotising enterocolitis (risk ratio (RR) 3.07, 95% confidence interval (CI) 0.50 to 18.77; participants = 141; studies = 2; low-quality evidence). Routine monitoring may increase the risk of feed interruption episodes (RR 2.07, 95% CI 1.39 to 3.07; participants = 141; studies = 2; low-quality evidence); the number needed to treat for an additional harmful outcome (NNTH) was 3 (95% CI 2 to 6).

Routine monitoring of gastric residual may increase time taken to establish full enteral feeds (mean difference (MD) 3.92, 95% CI 2.06 to 5.77 days; participants = 141; studies = 2; low-quality evidence), time taken to regain birth weight (MD 1.70, 95% CI 0.01 to 3.39 days; participants = 80; studies = 1; low-quality evidence), and number of total parenteral nutrition days (MD 3.29, 95% CI 1.66 to 4.92 days; participants = 141; studies = 2; low-quality evidence).

We are uncertain as to the effect of routine monitoring of gastric residual on other outcomes such as incidence of surgical necrotising enterocolitis, extrauterine growth restriction at discharge, parenteral nutrition-associated liver disease, duration of central venous line (CVL) usage, incidence of invasive infection, mortality before discharge, and duration of hospital stay. We found no data for outcomes such as aspiration pneumonia, gastroesophageal reflux, growth measures following discharge, and neurodevelopmental outcome.

Only one trial with 87 preterm infants met the inclusion criteria for the comparison of using two different criteria of gastric residual to interrupt feeds while monitoring gastric residual. The trial was done in infants with birth weight of 1500 to 2000 g. We are uncertain as to the effect of using two different criteria of gastric residual on outcomes such as incidence of necrotising enterocolitis or surgical necrotising enterocolitis, time to establish full enteral feeds, time to regain birth weight, number of total parenteral nutrition days, number of infants experiencing feed interruption episodes, extrauterine growth restriction at discharge, parenteral nutrition-associated liver disease, incidence of invasive infection, and mortality before discharge (very low quality evidence). We found no data on duration of CVL usage, aspiration pneumonia, gastroesophageal reflux, duration of hospital stay, growth measures following discharge, and neurodevelopmental outcome.

Share/Save