Over the years there have a number of studies comparing two different feeding regimes. Most recently there has been a comparison of 2 hourly vs 3 hourly feeds and a comparison of feeds every 3 hours compared to 4 feeds an hour.
The first of these randomized 150 babies in 2 Malaysian NICUs who were 1 to 1.5 kg birth weight to either being fed every 2 hours or every 3 hours (Ibrahim NR, et al. Two-hourly versus 3-hourly feeding for very low birthweight infants: a randomised controlled trial. Archives of Disease in Childhood – Fetal and Neonatal Edition. 2016). They were enrolled at the start of the feeds (average day 2) and the primary outcome was time to what they called “full enteral feeds” which was 100 mL/kg/d for 2 consecutive days. Which is quite a long way from full enteral feeds! Very few of the babies were getting breast milk (about 50%) feeds were increased by 15 to 20 mL/kg/d by protocol, but in fact it took 11 days (3 hour feed group) or 10 days (2 hour group) to reach 100 mL/kg/d. So in reality the increases were less than 10 mL/kg/d. There were no differences in any outcomes, neither the primary nor the secondaries, except for time to regain birth weight, which was slightly faster in the 3 hourly group. But there were several secondary outcomes, so the reliability of this data is doubtful.
The second study (Rovekamp-Abels LW, et al. Intermittent Bolus or Semicontinuous Feeding for Preterm Infants? Journal of pediatric gastroenterology and nutrition. 2015;61(6):659-64.) randomized nearly 250 babies of less than 1750 g birth weight to be fed by bolus feeds or what they called semicontinuous feeding. The babies all received minimal enteral nutrition “trophic feeds” starting on day one, which were given every 4 hours of 0.5 to 2 ml depending on birth weight. The next day they started increasing feeds, at 24 mL/kg/d on day 2 up to 120 mL/kg/d on day 6 if there were no hold ups. Bolus feeds were given every 3 hours, using gravity over 15 minutes. The “semicontinuous” feeds were given in the same daily volume, so each mini-feed was 1/12 the volume of the 3 hourly feed, by gravity via an open syringe attached to the NG tube that was topped up every 15 minutes during the day. The primary outcome in this study was the time to full enteral feeding, which in this case was 120 mL/kg/d. Dutch NICUs back-transfer babies very quickly, often when the baby has reached 120 mL/kg/d (which is when this group stops TPN) so there was a practical reason for choosing that outcome.
There were no differences in any outcome. The time to full feeding was indeed about 6 days on average (in both groups), with a very few babies holding out, being difficult to feed and still not on full feeds by 28 days (about 10% of them).
If you add these data to what is out there in the literature, there is no evidence that how we feed babies, bolus q3h or q4h, or continuous or semi-continuous, nor any evidence that increasing faster or slower, affects any important clinical outcome. In particular there is no evidence of any impact on NEC. Even starving babies for a few days compared to giving them trophic feeds doesn’t make a difference to NEC, though it may harm gut function and slow down the progression of feeds when they are eventually introduced (even that is not consistent in the literature). The only indication I think for not feeding babies is if they are in shock and you are concerned about gut perfusion. Otherwise we should be feeding babies early, increasing feeds as quickly as they can be tolerated, giving them breast milk, and ensuring they get probiotics.
One of the things that is fun sometimes is to read about some of the other practices and outcomes of centers who are presenting a study, things that slip into the manuscript.
In the first study, for example, the authors reported the outcome of reflux needing anti-reflux treatment, the reflux was “defined as unexplained apnoea/bradycardia based on clinical judgement and requiring anti-reflux treatment” : but as there is no association between apnea and reflux, no way to clinically diagnose reflux unless the baby is vomiting, and no anti-reflux treatment that is effective short of surgery, I have absolutely no idea what this is all about (but it wasn’t different between groups).
In the second study the authors give saline enemas to all babies who don’t pass meconium before 24 hours and then repeat them daily until the baby is pooping at the correct frequency. There is, of course, absolutely no evidence base for this practice. The other thing I noted was that the incidence of sepsis was very high, over 30% of the group of babies, who were under 1750 g enrolled in this trial (mean gestation 28.5 weeks) had at least one episode of sepsis. In comparison, recent data from the CNN show that babies under 1500 grams had about a 15% incidence of sepsis. Which makes me wonder if the 2 things are related, shooting saline up the bum of a small premie every 24 hours might be a good way to encourage translocation of enteral bacteria. I certainly can’t think it’s a good idea.