Use of caffeine in the NICU as a treatment for apnea of prematurity is a topic that has certainly seen it’s fair share of coverage on this blog. Just when you think there is an aspect of treatment with caffeine that hasn’t been covered before, along comes a new paper to change my mind.
The Caffeine for Apnea of Prematurity study or CAP, demonstrated that caffeine given between 3-10 days of age reduced the incidence of BPD in those treated compared to those receiving placebo. As an added benefit, in follow-up studies of these patients there appeared to be a benefit to neurodevelopmental outcomes as well at 18-21 months but this was lost by school age with groups being equivalent. In recent years evidence has mounted that starting caffeine earlier in the time course (<3 days and in many cases in the first hour after birth) has led to less need for intubation and BPD. What has really not been known though is whether the use of caffeine in this way might have any long term benefits aside from these short term outcomes.
Dr. Abhay Lodha from Calgary and a group of researchers led by Prakesh Shah from the Canadian Neonatal Network using our robust Canadian network data have tried to answer this with their paper Early Caffeine Administrationand Neurodevelopmental Outcomes in Preterm Infants
The group studied were <29 weeks’ gestation born between April 2009 and September 2011 and admitted to Canadian Neonatal Network centres. As defined in the paper “Neonates who received caffeine were divided into early- (received within 2 days of birth) and late-caffeine (received after 2 days of birth) groups. The primary outcome was significant neurodevelopmental impairment, defined as cerebral palsy, or a Bayley Scales of Infant and Toddler Development, Third Edition composite score of <70 on any component, hearing aid or cochlear implant, or bilateral visual impairment at 18 to 24 months’ corrected age.”
There were 2018 neonates included in the analysis with 1545 in the early group and 563 in the late. It is worth noting that there were 473 infants lost to follow-up meaning that there was about an 80% follow-up rate. Looking at the characteristics of those infants lost to follow-up there were no striking differences that one would expect between them and the group followed.
What did they find?
The odds of BPD (aOR 0.61; 95% CI 0.45–0.81), PDA (aOR 0.46; 95% CI 0.34–0.62), and Severe Neurologic Injury – parenchymal injury or GR III/IV IVH or PVL (aOR 0.66; 95% CI 0.45–0.97) were reduced in the early- caffeine group. The primary outcome was also found to be significantly different as per the table below demonstrating the odds after logistic regression analysis.
So early caffeine seems to be good. Is that all then?
I am very happy to see these results but a few questions remain. Before we get too enthusiastic, I find myself thinking back to the early 2000s after the initial CAP results showed an apparent difference in outcome. The question is whether the reduction in odds seen here for the primary outcome will persist as these children age. Will we see a tendency for the differences to vanish as these children enter school age? I suspect we might but that doesn’t mean all is lost here. What the authors have demonstrated clearly is that early caffeine is not harmful as there is no suggestion of those infants exposed to caffeine so shortly after birth fare worse than those treated later.
Also as the authors state, what isn’t clear is how caffeine works to decrease the risk of developmental impairment. In the discussion they offer some insightful thoughts as to what may be at play and I agree that certainly an anti-inflammatory effect may be responsible for some of the effect. I do wonder though if one could tie the reductions to the lower likelihood of BPD. Development of BPD has been shown many times over to be associated with worse developmental outcomes. Aside from the anti-inflammatory effect mentioned, could the avoidance of early intubation and therefore reduced risk of BPD from positive pressure ventilation be the reason?
In the end if the results persistent into school age, the reason won’t really matter and I hope it does. Will see what happens when we revisit this cohort in a few years but in the meantime I think this paper certainly confirms in my mind the need to give caffeine and make sure it’s provided early!
In July 2016 I published a blog post No more intubating for meconium? Not quite. In this post I highlighted the recent recommendations to modify the approach to the non vigorous infant born through meconium. The traditional approach of electively intubating such infants for tracheal suctioning before beginning PPV was replaced by provision of PPV first. The rationale here was that delaying the establishment of ventilation while trying to intubate for most situations was more risky than just trying to establish a functional residual capacity (FRC). The naysayers pointed out that while this recommendation is possibly warranted for less experienced intubators, perhaps in the hands of those with more skill, tracheal suctioning would be the better option if it could on average be done quickly.
It has been over two years since that recommendation and change in practice. Isn’t it about time someone looked at whether or not this was a good thing to do?
A Comparison of Two Time Periods
Chiruvolu A et al published Delivery Room Management of Meconium-Stained Newborns and Respiratory Support in this month’s Pediatrics. In this paper the authors compared 4 hospitals with a retrospective period of one year before the NRP changes (October 1, 2015, to September 30, 2016) to a one year prospective period (October 1, 2016, to September 30, 2017) after implementation of the new guidelines. In the retrospective cohort there were 11163 mothers delivered at ≥35 weeks’ gestation. Meconium stained amniotic fluid (MSAF) was present in 1303 (12%) deliveries with 130 (10%) of newborns who were nonvigorous. During the prospective time period, a total of 10 717 mothers delivered at ≥35 weeks’ gestation. MSAF was noted in 1282 (12%) deliveries, yielding 101 (8%) newborns who were nonvigorous. Therefore the study compared these 130 newborns in the retrospective cohort to the 101 in the prospective time period. The authors note that aside from the approach to MSAF there were no changes in care during this time in the delivery room.
A few differences exist though in the cohorts that are worth mentioning that were statistically significant. Firstly, the incidence of preterm and post-term infants were both higher in the prospective cohort (both 6% vs 1%). Secondly, the incidence of fetal distress was higher in the prospective cohort 57% vs 43%. All of these factors would tend to favour the retrospective cohort doing better than the prospective and so the authors in their results controlled for these differences. Not surprisingly the rate of intubation in the retrospective group was 70% vs 2% in the prospective arm.
What were the results?
The results shown in table 3 in terms of the Odds ratios have been adjusted for the aforementioned differences of preterm post-term and fetal distress. There are several things here worth noting. The risk of admission was significantly higher for respiratory distress. Oxygen needs and mechanical ventilation along with surfactant therapy were also notably higher. One things that showed no difference at all was the mean apgar score at 1 and 5 minutes. This is an interesting finding given the hypothesis that drove the change in practice. If establishing an FRC is the goal of the intervention to provide earlier PPV then shouldn’t the retrospective group have worse apgars due to less effective resuscitation? Maybe or maybe not. This really depends on the staff in the resuscitation room at the 4 hospitals. It might be that the staff were quite skilled so the intubations may have gone smoothly with minimal reductions in FRC compared to the prospective group. What would this study look like if done in a centre with less experienced people capable of intubation.
Also interesting in this study is that when isolating comparisons to those admitted to the NICU and those specifically diagnosed with MAS there were no differences between groups for such outcomes as length of stay, oxygen therapy, mechanical ventilation (MV) or days of MV. Given that the group sizes though were quite small (7 and 11 for MAS) we do have to take this data with a grain of salt as it really is too small to make any certain conclusions. A larger study would need to be done looking at these types of outcomes to really get a better handle on whether the approach to MSAF matters to these individual outcomes.
What this study does for me is raise an eyebrow. The change in practice does not seem to yield “better babies”. Secondly what we do see even when controlling for differences that would affect hospital admissions for respiratory distress is an increase in admission rate. In times when beds are becoming increasingly precious as census for many units swell one has to ask whether this approach is truly the better way to go. Perhaps it was wrong for the NRP to declare that for all practitioners it is best to provide PPV rather than intubate. This may have been too simplistic. If you have experienced intubators perhaps it would be best to continue to intubate first in this setting rather than provide PPV. What this study does is certainly raise questions and begs for a larger study to be done to determine whether these results can be replicated. If they are then I suspect the NRP may be headed down a different path for recommendations yet again.
In 2015 the Pediatric Endocrine Society (PES) published new recommendations for defining and managing hypoglycaemia in the newborn. A colleague of mine and I discussed the changes and came to the conclusion that the changes suggested were reasonable with some “tweaks”. The PES suggested a change from 2.6 mmol/L (47 mg/dL) at 48 hours of age as a minimum goal glucose to 3.3 mmol/L (60 mg/dL) as the big change in approach. The arguments for this change was largely based on data from normal preterm and term infants achieving the higher levels by 48-72 hours and some neuroendocrine data suggesting physiologically, the body would respond with counter regulatory hormones below 3.3 mmol/L.
As it turned out, we were “early adopters” as we learned in the coming year that no other centre in Canada had paid much attention to the recommendations. The inertia to change was likely centred around a few main arguments.
1. How compelling was the data really that a target of 2.6 and above was a bad idea?
2. Fear! Would using a higher threshold result in many “well newborns” being admitted to NICU for treatment when they were really just experiencing a prolonged period of transitional hypoglycaemia.
3. If its not broken don’t fix it. In other word, people were resistant to change itself after everyone was finally accustomed to algorithms for treatment of hypoglcyemia in their own centres.
What effect did it actually have?
My colleagues along with one of our residents decided to do a before and after retrospective comparison to answer a few questions since we embraced this change. Their answers to what effect the change brought about are interesting and therefore at least a in my opinion worth sharing. If any of you are wondering what effect such change might have in your centre then read on!
Skovrlj R, Marks S and C. Rodd published Frequency and etiology of persistent neonatal hypoglycemia using the more stringent 2015 Pediatric Endocrine Society hypoglycemia guidelines. They had a total of 58 infants in the study with a primary outcome being the number of endocrine consults before and after the change in practice. Not surprisingly as the graph demonstrates the number went up. Once the protocol was in place we went from arbitrary consults to mandatory so these results are not surprising. What is surprising though is that the median critical plasma glucose was 2.2 mmol/L, with no significant difference pre or post (2.0 mmol/L pre versus 2.6 mmol/L post, P=0.4) Ninety percent of the infants who were hypoglycemic beyond 72 hours of age were so in the first 72 hours. Of these infants, 90% were diagnosed with hyperinsulinemia. What this tells us is that those who are going to go on to have persistent hypoglycemia will demonstrate similar blood sugars whether you use the cutoff of 2.6 or 3.3 mmol/L. You will just catch more that present a little later using the higher thresholds. How would these kids do at home if discharged with true hyperinsulinemia that wasn’t treated? I can only speculate but that can’t be good for the brain…
Now comes the really interesting part!
Of the total infants in the study, thirteen infants or 40% had plasma glucose values of 2.6 to 3.2 mmol/L at the time of consultation after November 2015. Think about that for a moment. None of these infants would have been identified using the old protocol. Nine of these infants went on to require treatment with diazoxide for persistent hyperinsulinemia. All of these infants would have been missed using the old protocol. You might ask at this point “what about the admission rate?”. Curiously an internal audit of our admission rates for hypoglycemia during this period identified a decline in our admission rates. Concurrent with this change we also rolled out the use of dextrose gels so the reduction may have been due to that as one would have expected admission rates to rise otherwise. The other thing you might ask is whether in the end we did the right thing as who says that a plasma blood glucose threshold of 3.3 mmol/L is better than using the tried and true 2.6 mmol/L cutoff?
While I don’t have a definitive answer to give you to that last question, I can leave you with something provocative to chew on. In the sugar babies study the goal glucose threshold for the first 7 days of life was 2.6 mmol/L. This cohort has been followed up and I have written about these studies before in Dextrose gel for hypoglycemia. Safe in the long run? One of the curious findings in this study was in the following table.
Although the majority of the babies in the study had only mild neurosensory impairment detectable using sophisticated testing the question is why should so many have had anything at all? I have often wondered whether the goal of keeping the blood sugar above 2.6 mmol/L as opposed to a higher level of say 3.3 mmol/L may be at play. Time will tell if we begin to see centres adopt the higher thresholds and then follow these children up. I don’t know about you but a child with a blood sugar of 2.7 mmol/L at 5 or 6 days of age would raise my eyebrow. These levels that we have used for some time seem to make sense in the first few days but for discharge something higher seems sensible.
Recent statements by the American Academy of Pediatric’s, NICHD, the American College of Obstetricians and Gynecologists (ACOG), the Society for Maternal-Fetal Medicine (SMFM), and recommend selective approaches to mothers presenting between 22 0/7 to 22 6/7 weeks. The decision to provide antenatal steroids is only recommended if delivery is expected after 23 weeks. Furthermore the decision to resuscitate is based on an examination of a number of factors including a shared decision with the family. In practice this leads to those centres believing this is mostly futile generally not resuscitating or offering steroids while other more optimistic hospitals having higher rates of proactive (steroids and resuscitation) rates. Then there are other centres where the standard approach is proactive such as one in Uppsala, Sweden where this approach is used almost exclusively.
What would happen then if one compared the outcome for infants born at 22 weeks between this hospital and another where a selective approach is generally offered. In this case you would have a lot of experience with resuscitating infants at 22 weeks and the other a fraction of all presenting as a few to many would receive compassionate care. This is exactly what has now happened.
The authors examined a period from 2006-2015, dividing this time into two epochs with the first being 2006-2010 to account for differing practices and resources over time. Given that Uppsala took a proactive approach to all of their 40 live born infants during this time, it provided an opportunity to look at the 72 infants who were live born in the Ohio and examine their differences. In Ohio the approach was as follows; 16 (22%) received proactive care, 18 (25%) received inconsistent care (steroids but no resuscitation), and 38 (53%) received comfort care. In other words, although the total number of infants live born in Ohio was almost double that of Uppsala, only 16 were proactively treated in Ohio compared to all 40 in Uppsala.
The differences in outcome are striking
Survival in delivery room: (38/40, 95% vs 12/16, 75%; P = 0.049)
Provision of delivery room surfactant: (40/40, 100% vs 9/16, 56%; P<0.01)
Survival at 24 h (37/40, 93% vs. 9/16, 56%; P < 0.01).
Survival to 1 year (21/40, 53% vs. 3/16, 19%; P < 0.05).
Among the infants treated proactively, median age of death (17 postnatal days at range 0 h–226 days vs. 3 postnatal hours at NCH, range 0 h–10 days; P < 0.01).
All surviving infants had BPD All infants surviving to initial hospital discharge were alive at 18 months’ postnatal age.
With respect to long term outcome the authors note:
“Outpatient follow-up (qualitative or non-qualitative neurodevelopmental testing) was available in 26 out of 27 infants (96%) Eleven of the 26 (42%) were unimpaired, and all unimpaired infants were in the UUCH cohort. Among the 15 infants with impairment at UUCH, 3 had mild impairment and 12 had moderate or severe impairment. All surviving infants at NCH had moderate or severe impairment.”
A word about antenatal steroids as well. In Uppsala 85% of mothers received 2 doses of antenatal steroids vs 25% in Ohio. People sometimes question whether ANS at this age are effective. It is interesting to note that 44% of babies in the Ohio group vs 3% p<0.01 received chest compressions +/- epinephrine in the delivery room. Might this explain the better state of some of these infants at birth?
The Power of Belief
When I do rounds I often remark that try as we might we can’t will babies to do better. I also commonly say however that we need to be optimistic and although I am accused of seeing the world through rose coloured glasses I think there is an important lesson to be learned from this study. This comparison is really a contrast between a system that believes they can do a good thing for these families by actively promoting a proactive approach vs a system in which I imagine a reluctant approach exists even for those infants where a proactive plan is enacted. One sign of this might be that in Sweden 100% of these deliveries had a Neonatologist present vs 75% in the US. It could be due to other factors such as ability of the Neo to get in within time of the delivery however rather than a sign they didn’t feel they were needed due to futility.
There is evidence as well that the aggressiveness of the proactive approach also differs between the two sites based on a couple observations. The first is the rate of surfactant provision in the delivery room which was 100% in Sweden but only 56% in the US. The other thing of note is the time of death for those who did not survive. The median time of death in the US was 3 hours vs 17 days in Uppsala. What does this tell us about the approaches? I would imagine (although the numbers are small) that the teams in the US were much more likely to lose hope (or faith) and withdraw early while the other centre possibility motivated by their past successes pushed forward.
Remarkably, although one might think that the teams in Uppsala were simply creating significantly impaired survivors, 42% of the survivors were unimpaired from a developmental standpoint in follow-up. All surviving infants though from Ohio had moderate to severe impairment.
What this story may also really be about is practice. The reality is that the team in Sweden had over twice the exposure to such infants over time. Although the number presenting at this GA was higher, the ones that actually were resuscitated and given steroids was less than half. One cannot take away though that Uppsala in the end demonstrated that a proactive approach is definitely not futile. Not only can these children survive but almost half will be developmentally intact.
We must acknowledge as well though that since this is a retrospective study there may be factors that may have affected the results. As the saying goes “Individual results may vary”. Are the teams the same in both centres in terms of number of Neonatologists? Are there more residents caring for these infants vs fellows? Are the resources the same? What about proximity of the Neonatologist to the hospital? There are other factors such as cohesiveness of the team and communication between team members that may be influencing the results.
In the end though, this is a story of a team that believed it could and did. Perhaps seeing the world through rose coloured glasses is not such a bad thing in the end.
Look around an NICU and you will see many infants living in incubators. All will eventually graduate to a bassinet or crib but the question always is when should that happen? The decision is usually left to nursing but I find myself often asking if a baby can be taken out. My motivation is fairly simple. Parents can more easily see and interact with their baby when they are out of the incubator. Removing the sense of “don’t touch” that exists for babies in the incubators might have the psychological benefit of encouraging more breastfeeding and kangaroo care. Both good things.
Making the leap
For ELBW and VLBW infants humidity is required then of course they need this climate controlled environment. Typically once this is no longer needed units will generally try infants out of the incubator when the temperature in the “house” is reduced to 28 degrees. Still though, it is not uncommon to hear that an infant is “too small”. Where is the threshold though that defines being too small? Past research studies have looked at two points of 1600 vs 1800g for the smallest of infants. One of these studies was a Cochrane review by New K, Flenady V, Davies MW. Transfer of preterm infants for incubator to open cot at lower versus higher body weight. Cochrane Database Syst Rev 2011;(9). This concluded that early transition was safe for former ELBWs at the 1600g weight cut off.
What about the majority of our babies?
While the ELBW group takes up a considerable amount of energy and resources the later preterm infants from 29 to 33 6/7 weeks are a much larger group of babies. How safe is this transition for this group at these weights? Shankaran et al from the NICHD published an RCT on this topic recently; Weaning of Moderately Preterm Infants from the Incubator to the Crib: A Randomized Clinical Trial. The study enrolled
Infants in this gestational age range with a birth weight <1600g were randomly assigned to a weaning weight of 1600 or 1800 g. Within 60 to 100 g of weaning weight, the incubator temperature was decreased by 1.0°C to 1.5°C every 24 hours until 28.0°C. Weaning to the crib occurred when axillary temperatures were maintained 36.5°C to 37.4°C for 8 to 12 hours. Clothing and bedcoverings were standardized. The primary outcome was LOS from birth to discharge.
What did they find?
A total of 366 babies were enrolled (187 at 1600g and 179 at 1800g. Baseline characteristics of the two groups revealed no statistical differences. Mean LOPS was a median of 43 days in the lower and 41 days in the higher weight group (P = .12). After transition to a crib weight gain was better in the lower weight group, 13.7 g/kg/day vs 12.8 g/kg/ day (P = .005). Tracking of adverse events such as the incidence of severe hypothermia did not differ between groups. The only real significant difference was a better likelihood of weaning from the incubator in the higher group at 98% success vs 92% on the first attempt. Putting. That in perspective though, a 92% success rate by my standards is high enough to make an attempt worthwhile!
The authors have essentially shown that whether you wean at the higher or lower weight threshold your chances of success are pretty much the same. Curiously, weight gain after weaning was improved which seems counter intuitive. I would have thought that these infants would have to work extra hard metabolically to maintain their temperature and have a lower weight gain but that was not the case. Interestingly, this finding has been shown in another study as well; New K, Flint A, Bogossian F, East C, Davies MW. Transferring preterm infants from incubators to open cots at 1600 g: a multicentre randomised controlled trial. Arch Dis Child Fetal Neonatal Ed 2012;97:F88-92. Metabolic rate has been shown to increase in these infants but skin fold thickness has been shown to increase as well in infants moved to a crib. How these two things go together is a little beyond me as I would have thought that as metabolic rate increases storage of tissue would slow. Not apparently the case but perhaps just another example of the bodies ability to overcome challenges when put in difficult situations. A case maybe of “what doesn’t kill you makes you stronger?”
The authors do point out that the intervention was unmasked but the standardization of weaning procedure and garments used in the cribs should have overcome that. There were 36% of parents who did not consent to the study so their inclusion could have swayed the results perhaps but the sample size here was large despite that. That the final results agree with findings in ELBW infants suggests that the results are plausible.
What I think this study does though is tell us overall that weaning at a smaller weight is at least alright to try once one is at minimal settings in an incubator. Will this change your units practice? It is something that at least merits discussion.