Hypoglycemia has been a frequent topic of posts over the last few years. Specifically, the use of dextrose gels to avoid admission for hypoglycemia and evidence that such a strategy in not associated with adverse outcomes in childhood. What we know is that dextrose gels work and for those centres that have embraced this strategy a reduction in IV treatment with dextrose has been noted as well.
Dextrose gels however in the trials were designed to test the hypothesis that use of 0.5 mL/kg of 40% dextrose gel would be an effective strategy for managing hypoglycemia. In the Sugar Babies trial the dextrose gel was custom made and in so doing an element of quality control was made possible.
In Canada we have had access to a couple products for use in the newborn; instaglucose and dex4. Both products are listed as being a 40% dextrose gel but since they are not made in house so to speak it leaves open the question of how consistent the product is. Researchers in British Columbia sought to examine how consistent the gels were in overall content and throughout the gel in the tube. The paper by A. Solimano et al is entitled Dextrose gels for neonatal transitional hypoglycemia: What are we giving our babies? As an aside, the lead author Alfonso was just announced as the 2019 recipient of the Canadian Pediatric Society Distinguished Neonatologist award so I couldn’t see a better time to provide some thoughts on this paper!
What did they find?
The study examined three tubes each of instaglucose and dex4. For each tube the researchers sampled dextrose gel from the top, middle and bottom and then the dextrose content per gram of gel determined as well as gel density. Glucose concentrations were analyzed high-pressure liquid chromatography tandem mass spectrometry (HPLC-MS/MS) and gas chromatography mass spectrometry (GCMS) were used to determine glucose concentrations and identify other carbohydrates, respectively. In terms of consistency the gels were found to be quite variable with dextrose content that for instaglucose could be as much as 81% and 43% different for dex4. Differences also existed between the different sections of the tubes so depending on the whether it was a fresh tube you were using or not the amount of dextrose could vary.
The authors also discovered that while dex4 contained almost exclusively dextrose, instaglucose contained other carbohydrates not listed on the manufacturer’s ingredient list.
What does it all mean?
The differences are interesting for sure. If the glucose gels are not consistent though should we stop using them? I think the answer to that at least for me is no. Although the data is unpublished, our own centres experience has been that admissions for hypoglycemia have indeed fallen since the introduction of dextrose gel usage (we use instaglucose). What I can only surmise is that in some cases patients may be getting 40% but perhaps in others they are getting as little as 20% or as much as 60% (I don’t know exactly what the range would be but just using this as an example). In some cases of “gel failure” perhaps it is for some babies, receipt of low dextrose containing gel that is at fault or it may be they just have high glucose requirements that gel is not enough to overcome. Other infants who respond quickly to glucose gel may be getting a large dose of dextrose in comparison. Overall though, it still seems to be effective.
What I take from this study is certainly that there is variation in the commercially prepared product. Producing the gel in the hospital pharmacy might allow for better quality control and would seem to be something worth pursuing.
It isn’t often in Neonatology these days that something truly innovative comes along. While the study I will be discussing is certainly small I think it represents the start of something bigger that we will see evolve over the coming years.
There is no question that the benefits of mother’s own milk are extensive and include such positive outcomes as improved cognition in preterm infants and reductions in NEC. The benefits come from the immunological properties as well as the microbiome modifying nature of this source of nutrition and have been discussed many times over. Mother’s own milk contains a couple of very special things that form the basis of the reason for the study to be presented.
What are neurotrophins and stem cells?
Before discussing the study it is important to understand what these two classes of molecules and cells are capable of. Neurotrophins are molecules that have the capability of promoting growth and survival of neural cells. Included in this class are EGF, brain-derived neurotrophic factor, glial derived neurotrophic factor, nerve growth factor, insulin-like growth factor-1, and hepatic growth factor. It turns out that not only are these found in high concentrations in breast milk but that a woman who produces breast milk at early gestational ages has higher amounts of these substances in her milk. Pretty convenient that substances promoting development of the brain and survival of brain cells increase the earlier you deliver! Stem cells are pluripotent cells meaning that they can develop into pretty much any cell type that they need to in the body. This would come in handy for example if you needed some new cells in the brain after a neurological insult. These are also present in mother’s milk and in fact can represent as much as 30% of the population of cells in breast milk.
The Nasal Cavity and the Brain
Clearly, the distance from the nasal cavity to the brain is relatively short. Without going into exhaustive detail it has been demonstrated in animal models that provision of medications intranasally can reach the brain without traversing the blood stream. This affords the opportunity to provide substances to the neonate through the nasal cavity in the hopes that it will reach the brain and achieve the desired effect. When you think about it, newborns when feeding have contact between the whole nasopharyngeal cavity and milk (as evidenced by milk occasionally dripping out of the nose when feeding) so using an NG as we do in the NICU bypasses this part of the body. Is that a good thing?
Intranasal application of breast milk
Researchers in Germany led by Dr. Kribs published an early experience with this strategy in their article Intranasal breast milk for premature infants with severe intraventricular hemorrhage—an observation. In this paper the strategy;follows; 2 × 0.1 ml of his or her mother’s milk 3 to 8 times a day (0.6 to 1.6 ml total per day). The breast milk was freshly expressed, which means the milk was used within 2 h after expression. The daily application started within the first 5 days of life and was continued for at least 28 days to a maximum of 105 days.
The outcome of interest was whether the severe IVH would improve over time compared to a cohort of infants with severe IVH who did not receive this treatment. Importantly this was not a randomized trial and the numbers are small. A total of 31 infants were included with 16 receiving this treatment and 15 not. The two groups were compared with the results as follows.
The results don’t reach statistical significance but there is a trend at the bottom of the table above to having less progressive ventricular dilatation and surgery for the same. Again this is a very small study so take the results with a grain of salt!
Is this practice changing? Not yet but it does beg the question of what a properly designed RCT might look like. The authors predict what it might look like with a sham nasal application versus fresh mother’s milk. I do wonder though if it may become a study that would be hard to recruit into as when families are approached and the potential benefit explained it may be hard to get them to say anything other than “Just give my baby the breast milk!” Such is the challenge with RCTs so it may be that a larger retrospective study will have to do first. Regardless, be on the lookout for this research as I suspect we may see more studies such as this coming and soon!
* Featured image from the open access paper. (There couldn’t be a better picture of this out there!)
