To say this has been a labour of love is an understatement. So many people have contributed to the new position statement for the Canadian Pediatric Society (CPS).
My co-author Dr. Seth Marks from Pediatric Endocrinology spent countless hours reviewing the evidence and fielding seemingly endless questions from reviewers and myself. The support from the CPS was also much appreciated as the back and forth from so many who expressed opinions would have been difficult to manage without their support. What I hope you will find as you read this is the best appraisal of the evidence and directions for care that we could come to in 2019. Where things will stand by the time we make it to the next revision will be interesting to see.
Big Accomplishment
For those who have used the Acute Care of At Risk Newborns (ACORN) program you will be pleased to know that the upcoming new version of this program is completely alligned with the approach outlined in the CPS statement. Given that the first version of ACORN and the CPS were not aligned and caused great discussion and distress at times, we feel this is a big accomplishment.
The algorithm for managing hypoglycemia is clean and easy to follow (I think) and we hope such clarity will greatly help with managing those infants at risk.
Main Questions for the Future
We remain a country divided (much like the recent election) with respect to dextrose gels usage. There are centres which are leary of using adult formulations of dextrose gel in newborns whereas others have adopted such treatments with success. The algorithm and statement address the approach to using dextrose gels or what to do if one wishes to avoid such use. With time, local products or a national brand designed specifically for newborn use may come to be and this will need to be addressed at some point.
Changing the threshold at 72 hours and beyond to require glucose levels of greater than or equal to 3.3 mmol/L may lead some to be worried about a ramp up in admissions but at least locally we have not seen this. In the end those with persistent causes of hypoglycemia will manifest one way or the other and whether it is before or after discharge from the hospital may be a reflection of what threshold you feel comfortable using.
Will local guidelines be affected by adopting the changes outlined in this statement? I suspect so and would welcome feedback before the next version of this document is worked on to determine what if any ramifications (positve or negative) such approaches have had.
No doubt with many changes compared to the previous version of the statement there may be some surprises. Keep an open mind and look at the evidence presented. In other cases the lack of evidence has motivated a change in position. Either way we believe this is the best approach to care for at risk newborns given what we know today.
First off I should let you know that we do not do transpyloric feeding for our infants with BPD. Having said that I am aware of some units that do. I suspect the approach is a bit polarizing. A recent survey I posted to twitter revealed the following findings:
I think the data from this small poll reveal that while there is a bias towards NG feeds, there is no universal approach (as with many things in NICU).
Conceptually, units that are using transpyloric feeds would do so based on a belief that bypassing the stomach would lead to less reflux and risk of aspiration. The question though is whether this really works or not.
New N of 1 Trial
I don’t think I have talked about N of 1 trials before on this site. The trials in essence allow one patient to serve as a study unto themselves by randomizing treatments over time for the single patient. By exposing the patient to alternating treatments such as nasogastric or nasoduodenal feedings one can look at an outcome and get a sense of causality if a negative or positive outcome occurs during one of the periods consistently. That is what was done in the study Individualising care in severe bronchopulmonary dysplasia: a series of N-of-1 trials comparing transpyloric and gastric feeding by Jensen E et al from the Children’s Hospital of Philadelphia. The authors in this study determined that using a primary outcome of frequency of daily intermittent hypoxaemic events (SpO2 ≤80% lasting 10–180 s) they would need 15 patients undergoing N of 1 trials between nasogastric and nasoduodenal feeding. Included infants were born at <32 weeks and were getting positive airway pressure and full enteral nutrition at 36 0/7 to 55 6/7 weeks PMA. Infants who were felt to be demonstrating signs of reflux or frank regurgitation were enrolled.
The findings
Thirteen of 15 enrolled patients completed the study. The two who did not complete did so as their oxygen requirements increased shortly after starting the trial and the clinical team removed them and chose their preferred route of feeding. Randomization looked like this:
Of the 13 though that completed and using an intention to treat analysis of the other two the findings were somewhat surprising. Contrary to what one might have thought that transpyloric would be a lung protective strategy, the findings were opposite.
Overall the combined results from these 15 patients demonstrated that nasogastric feedings were protective from having intermittent hypoxic events.
How can this be explained?
To be honest I don’t really know but it is always fun to speculate. I can’t help but wonder if the lack of milk in the stomach led to an inability to neutralize the stomach pH. Perhaps distension has nothing to do with reflux and those with BPD who have respiratory distress with some degree of hyperinflation simply are prone to refluxing acid contents due to a change in the relationship of the diaphragmatic cura? It could simply be that while the volume in the stomach is less, what is being refluxed is of a higher acidity and leads to more bronchospasm and hypoxemic events.
What seems to be clear even with this small study is that there really is no evidence from this prospective trial that transpyloric feeding is better than nasogastric. Given the size of the study it is always worth having some degree of caution before embracing wholeheartedly these findings. No doubt someone will argue that a larger study is needed to confirm these findings. In the meantime for those who are routinely using the transpyloric route I believe what this study does at the very least is give reason to pause and consider what evidence you have to really support the practice of using that route.
The Ortolani and Barlow manouvers are probably the two most requested parts of the physical exam that students ask to be shown. We line up several medical students who take turns applying the steps of abduction and then adduction, testing the stability of the hips. We routinely give oral sucrose, position in kangaroo care or breastfeed while performing other noxious stimuli such as heel lancing but at least in my centre give nothing for manipulating the hips in such a fashion.
How can we determine if a newborn feels pain?
In a recent paper entitled Neurophysiological and behavioral measures of pain during neonatal hip examination by Pettersson M et al they used three methods to assess pain during the newborn hip exam. These were the Premature Infant Pain Profile‐Revised (PIPP‐R) scale which is generally used for such assessment as well as two relatively novel ways in the use of near‐infrared spectroscopy (NIRS) and galvanic skin response (GSR). In essence if the a region of the brain becomes more active during a painful experience more oxygen will be extracted during that time. By using auscultation of heart rate with a stethoscope as a control procedure which should not elicit pain the authors were able to compare in a controlled fashion 28 newborns undergoing both activities. The use of NIRS was previously demonstrated as valid in the paper Pain activates cortical areas in the preterm newborn brain. Galvanic skin response has also been demonstrated to correlate with pain and measures changes in skin conductance in the paper Skin conductance compared to a combined behavioural and physiological pain measure in newborn infants.
So the authors set out to compare findings in these 28 infants and standardized the study as much as they could by having one Neonatologist perform all hip exams and having a video recording of the infant’s face during the procedure assessed by two independent reviewers in order to assign the PIPP-R scores. While not a randomized trial, for the type of intervention being studied this was the right approach to take to determine the answer to their question.
The Findings
Interesting findings indeed. Statistically significant differences were noted in bilateral changes in oxygen extraction during hip examination as well as for the GSR small peaks. The PIPP-R scores as well were vastly different between the two groups suggesting that the areas of the brain responsible for perception of pain were indeed activated more so with manipulation of the hip than with auscultation of the heart.
What can we take from this?
The hip exam may elicit responses indicating pain but there remains the question of how much is actually elicited. Nonetheless, the authors findings are intriguing as they certainly challenge the notion that this is a quick exam that should be just done and gotten over with. Clearly bundling or Kangaroo Care are not an option here due to the nature of what is being done. The next time you are planning on doing such tests though should you at least consider non-nutritive sucking on a pacifier or sucrose solution if readily available? If not readily available then should it be?
