We all know the truth deep inside: The gastric residual (GR) is a meaningless sign. My sense, in speaking to audiences around the country, is that more and more NICUs are deciding that they too have had it with the GR. Many are stopping the practice of looking.
Why has checking the GR lasted so long? Possibly because the GR check serves two purposes: The first is as a measure of feeding intolerance, and the second is that it is the preferred method to ensure that the enteral feeding tube is in the correct place.
And yet, a good test needs to be highly sensitive, highly specific, or both. The sensitivity of a test represents the percentage when a sign is positive in the face of true disease. On the other hand, specificity of a test represents the percentage when a sign is positive that this actually represents true disease.
The GR check is neither sensitive nor specific.
What about GR fluid volume and color?
Research has shown that there is almost 3 mL in the stomach of normal preterm infants who are NOT fed, which makes it almost laughable that we quibble about 0.5 to 1 mL of GR in clinical practice.
Since backwash in the stomach is very common in preterm infants, color is also practically meaningless. I would say that the only true colors that matter are those of blood: frank red color or coffee ground after it has been in acid for some time. Blood is a real sign and suggestive that some mucosal injury has taken place. However, this in of itself does not determine what we need to do such as hold feeds, lavage the stomach, or start an acid block medicine, or simply adjust the feeding tube – but it is real.
The other color that is much more associated with trouble is deep, dark, kale-green, which occurs in the presence of significant intestinal obstruction. This is accompanied by many other signs of obstruction, including marked abdominal distention. That being said, I have on occasion seen this color in benign scenarios, so I am still more suspect of green. The literature suggests that color really is not helpful, however.
Traditional practice: The fear factor
Fear drives many of our practices. Think about the recent momentum in reducing antibiotic use in the Vermont Oxford Network, and here in California with our perinatal quality network CPQCC, and we see some similarities.1 As neonatal providers, we are often guided by fear. Death by sepsis is shocking and leaves a lasting impression on our minds. It certainly has for me.
We have reflexively covered infants empirically for decades in the hopes of avoiding these situations playing out. However, data from research can lead us out of the dark, and show that it may be alright to move the needle back the other direction. We are now very aware that we have been providing excessive antibiotic to many of our newborns.
Fear example 1: Gastric dysmotility
The underlying cause of the gastric residual is poor gastric function or motility. The stomach is stupid at an early age, especially in the preterm period. Immature migratory complexes, poor enterohormone signaling, and a relative ease for retroperistalsis so that biliary contents reach the stomach, make interpretation of the GR fraught with error. It is a signal for one clear thing: gastric dysmotility, and probably not much more.
The problem and clinical recognition is that the presence of gastric dysmotility can be there even in the face of normal intestinal function where bowel sounds are heard, feeds are otherwise tolerated, abdominal exams are normal, and the coup de grace of bowel function, stool, is appearing at the other end. Again this challenges the value of this test (sensitive and specific) to guide management on its own.
Fear example 2: Cardiac murmur
Let me give you another example whereby we spend far too much time pondering a clinical sign of dubious significance: the cardiac murmur to determine presence or absence of the patent ductus arteriosus (PDA). The universal response by the medical team, when asked if they think there is a significant PDA playing a role in a preterm infant, is whether the individual has or has not heard a murmur. My response to this may sound heretical, but I really don’t care about the murmur.
A murmur can be present often, but not exclusively when the ductus is open. In fact, the largest ductus recapitulate fetal circulation and have pure laminar flow and therefore a murmur is often not present. A fully closed ductus can also be associated with a loud and persistent murmur due to turbulence of flow across the pulmonary artery.
So as a clinical finding, hearing a murmur is neither very sensitive nor specific for a PDA, making it unworthy to emphasize this up front. Rather, measures of pulmonary overcirculation or systemic hypoperfusion are far more valuable in assessing the hemodynamic consequences of the PDA. Nevertheless, I will still listen to the heart on rounds – but really more for show.
The message is that we lean on habit, on crowd thinking, and are driven many times in making decision out of fear and not fact. In the area of the GR we have been in the dark largely because we have not had enough data to rid this practice.
Are we ready for the change?
Some challenges from the literature have recently come out that make me think that we may rapidly move towards a tipping point on stopping to react to the GR very soon. A study published this year from Israel showed that avoiding routing measurement of the GR resulted in faster time to full feeds and larger discharge weights.2 The study was too small to look at complications such as NEC, yet it was reassuring to see there were no differences here.
Studies have also demonstrated that refeeding gastric residuals was not associated with harm, but also did not accelerate time to full feeding.3 The most comprehensive call to action was data and review from Florida that questioned the practice of checking GR and showing faster feeding and reduced parenteral nutrition use.4,5
If we overinterpret the GR, why should that matter? I’ll tell you. An example of overinterpretation is this: The result of us overusing antibiotics out of fear has created long term issues for preterm infants that we are only beginning to understand and document.2 There were several unanticipated costs of doing such business. The most poignant example is the disruption of the gut microbiome, which we are finding holds metabolic and long-term health advantages.
The response to the GR check could be a benign watch-and-see, but far too often there is discarding of valuable nutrition, holding of feeds, prolonging parenteral nutrition, starting antibiotics, and starting acid blocking medications – the latter two being associated with the development of NEC. Our fear-driven practice may be in fact self-fulfilling in promoting the very condition we are trying to avoid.
A better feeding tube check
We are desperately in need of an alternative to the feeding tube position check. There are several examples in the literature trying to resolve this, including putting different materials in the tubing, measuring pepsin in the GR, placing detectable materials on the tip of the tube, etc. None have risen high enough in accuracy to supercede the current faulty gold standard of hearing a pop. Innovators out there, this is a call to action to try harder to find a viable alternative.
It pains me to see exuberant efforts to pull back on a syringe to prove that all has been evacuated, only to get some blood tinging of the GR from such exuberance. What untoward effects are we causing and not tracking?
Time to say farewell
I may be wrong, but I believe we are on the edge of another wave of adoption of a change in practice: going blind to the GR. With the more recent data, I see more and more NICUs confessing that they have changed over to a non-reactive mode to the GR. GR may still be checked as part of tube placement, however the reporting of the GR to the medical team to react is possibly going away.
It would be great if more studies help validate this GR blind practice, but as we have seen in other scenarios where practice outpaces the data (e.g. oral colostrum care) this trend may have a mind of its own.
So goodbye, dreaded gastric residual. Your menacing and misguided presence is about to come to an end.
- Schulman J, Dimand RJ, Lee HC, Duenas GV, Bennett MV, Gould JB. Neonatal
intensive care unit antibiotic use. Pediatrics. 2015 May;135(5):826-33. doi:
10.1542/peds.2014-3409. Epub 2015 Apr 20. PubMed PMID: 25896845.
- Riskin A, Cohen K, Kugelman A, Toropine A, Said W, Bader D. The Impact of
Routine Evaluation of Gastric Residual Volumes on the Time to Achieve Full
Enteral Feeding in Preterm Infants. J Pediatr. 2017 Jun 15. pii:
S0022-3476(17)30747-3. doi: 10.1016/j.jpeds.2017.05.054. [Epub ahead of print]
PubMed PMID: 28625498.
- Salas AA, Cuna A, Bhat R, McGwin G Jr, Carlo WA, Ambalavanan N. A randomised
trial of re-feeding gastric residuals in preterm infants. Arch Dis Child Fetal
Neonatal Ed. 2015 May;100(3):F224-8. doi: 10.1136/archdischild-2014-307067. Epub
2014 Dec 31. PubMed PMID: 25552280.
- Li YF, Lin HC, Torrazza RM, Parker L, Talaga E, Neu J. Gastric residual
evaluation in preterm neonates: a useful monitoring technique or a hindrance?
Pediatr Neonatol. 2014 Oct;55(5):335-40. doi: 10.1016/j.pedneo.2014.02.008. Epub
2014 Aug 14. Review. PubMed PMID: 25129325.
- Torrazza RM, Parker LA, Li Y, Talaga E, Shuster J, Neu J. The value of routine
evaluation of gastric residuals in very low birth weight infants. J Perinatol.
2015 Jan;35(1):57-60. doi: 10.1038/jp.2014.147. Epub 2014 Aug 28. PubMed PMID:
25166623; PubMed Central PMCID: PMC5446673.