I think my first training in resuscitation began with the principles outlined in the NRP 3rd edition program. As we have moved through subsequent editions with the current edition being number 7, I can’t help but think about how many changes have occurred over that time. One such change has been the approach to using medications as part of a resuscitation. Gone are such things as calcium gluconate, naloxone and sodium bicarbonate but something that has stood the test of time is epinephrine. The dosing and recommendations for administering epinephrine have changed over time as well with the dose of endotracheal medication increasing from 0.01 to 0.03 and now to 0.05 – 0.1 mg/kg. While this dosing has increased, that of IV administration has remained the same at 0.01 to 0.03 mg/kg. The change in dosing for the ETT route was due to an increasing awareness that this route just isn’t as effective as IV. Having said that with only 0.1% of resuscitations requiring such support the experience with either route is fairly limited.
What is the concern?
Giving a medication directly via the IV route ensures the dose reaches the heart in the amount desired. In the case of ETT administration there are a few potential issues along the way. The first is that one needs to push the dose down the ETT and this presumes the ETT is actually in the trachea (could have become dislodged). Secondly, if the medication is sent to the lung what effect does the liquid component in the airways have in terms of dilution and distribution of the medication? Lastly, even if you get the epinephrine to the lung it must be picked up at the capillary level and then returned to the left side of the heart. In the absence of significant forward pulmonary blood flow this is not assured.
What is the evidence?
In terms of human clinical research it remains fairly limited. Barber published a retrospective review of 47 newborns who received epinephrine via the endotracheal route. The study Use and efficacy of endotracheal versus intravenous epinephrine during neonatal cardiopulmonary resuscitation in the delivery room found that spontaneous circulation was restored in 32% of this cohort. Following the first dose, a subsequent dose of intravenous epinephrine restored circulation in 77%. This study provided the first suggestion that the IV route may be better than endotracheal. Keep in mind though that this study was retrospective and as the authors conclude in the end, prospective studies are needed to confirm these findings. The question really is what is the likelihood of restoring circulation if the first dose is given IV?
Eleven years later we have a second study that attempts to answer this question although once again it is retrospective. Efficacy of Intravenous and Endotracheal Epinephrine during NeonatalCardiopulmonary Resuscitation in the Delivery Room by Halling et al. This study really was designed to answer two questions. The study group looked at the period from July 2006 to July 2014. During this period the dose of IV epinephrine remained unchanged as per NRP recommendations but the dose of endotracheal epinephrine increased from 0.01 to 0.03 and then to 0.05 mg/kg endotracheally. The increase was in response to both NRP and site observations that the lower doses were not achieving the effect they were hoping for.
The Results
ETT epinephrine
IV Epinephrine
Number
30
20
Return of circulation
23
15
1 dose
6
4
2 dose
5
8
3 doses
9
0
4 doses
3
3
In the ETT group all doses except for 3 after the first dose were given as IV. There was no difference in the response rate over time suggesting that higher doses do not truly increase the chance of a better response. The authors noted that the effectiveness of the two arms were not that different despite a significantly higher dose of epinephrine being administered to the group receiving ETT epinephrine first which is not surprising given the higher recommended dosages.
What I find interesting though is that giving the first dose of epinephrine was given IV in 20 of the paitents, if it is indeed the better route one might expect a better response than in the ETT group. The response from one dose of ETT epi was 20% while that from the IV first group was in fact also only 20%! We do indeed need to be careful here with small numbers but the results at least to me do not suggest strongly that giving IV epi first ensures success. What the study suggests to me is that two doses of epinephrine may be needed to restore circulation. If you choose to start with IV it certainly does not seem unwise but if you have any delays I don’t see any reason to avoid ETT epinephrine as your first line.
The reality is that for many individuals a UVC is a procedure that while they may have learned in an NRP class they may have never actually placed one. Having an ETT in place though seems like a good place to start. I doubt we will ever see a randomized trial of ETT vs IV epinephrine in Neonatology at this point given the stance by the NRP so these sorts of studies I suspect will be the best we get.
For now, based on what is out there I suggest use the route that you can get first but expect to need additional doses at least one more time to achieve success. Lastly remember that even if you do everything correct there will be some that cannot be brought back. Rest assured though that if the first dose was given via ETT you have still done your best if that was the route you had.
The human body truly is a wondrous thing. Molecules made from one organ, tissue or cell can have far reaching effects as the products take their journey throughout the body. As a medical student I remember well the many lectures on the kidney. How one organ could control elimination of waste, regulate salt and water metabolism, blood pressure and RBC counts was truly thought provoking. At the turn of the century (last one and not 1999 – 2000) Medical school was about a year in length and as the pool of knowledge grew was expanded into the three or four year program that now exists. Where will we be in another 100 years as new findings add to the ever growing volume of data that we need to process? A good example of the hidden duties of a molecule is erythropoetin (Epo) the same one responsible from stimulating red blood cell production.
Double Duty Molecule
In saying that I am simplifying it as there are likely many processes this one hormone influences in the body but I would like to focus on its potential role in neuroprotection. In 1999 Bernaudin Et al performed an animal study in mice to test this hypothesis. In this elegant study, strokes were induced in mice and the amount of Epo and Epo receptors measured in injured tissues. Levels of both increased in the following way “endothelial cells (1 day), microglia/macrophage-like cells (3 days), and reactive astrocytes (7 days after occlusion)”. To test the hypothesis that the tissues were trying to protect themselves the authors then administered recombinant human Epo (rhEpo) to mice prior to inducing stroke and the injury was clearly reduced. This established Epo as a potential neuroprotectant. Other animal studies then followed demonstrating similar findings.
A Human Trial
When you think about hypoxic ischemic encephalopathy (HIE) you can’t help but think of whole body cooling. The evidence is pretty clear at this point that cooling in this setting reduces the combined outcome of death or neurodevelopmental disability at 18 months with a number needed to treat of 7. The risk reduction is about 25% compared to not those not cooled so in other words there is room to improve. Roughly 30-40% of infants who are cooled with moderate to severe HIE will still have this outome which leaves room for improvement. This was the motivation behind a trial called High-Dose Erythropoietin and Hypothermia for Hypoxic-Ischemic Encephalopathy: A Phase II Trial. This was a small trial comparing 50 patients (24 treated with rhEpo and cooling to 26 given placebo) who were treated with 1000 U of rEpo on days 1,2,3,5 and 7. Primary outcome was neurodevelopment at 12 months assessed by the Alberta Infant Motor Scale (AIMS)and Warner Initial Developmental Evaluation. A significant improvement in a subset of mobility on the latter was found and a significant difference in the AIMS overall. An additional finding giving support for a difference was that blinded reviews of MRI scans demonstrated a singificant improvement in brain tissue in those who received rhEPO. One curious finding in this study was that the mean timing of administration of rhEPO was 16.5 hours of life. Knowing that the benefit of cooling is best when done before 6 hours of age one can only wonder what impact earlier administration of a neuroprotective agent might have. This suggests that the addition of rEPO to cooling has additional impact but of course being a small study further research is needed to corroborate these findings.
The Next Step
This past week Malla et al published an interesting paper to add to the pool of knowledge in this area; Erythropoietin monotherapy in perinatal asphyxia with moderate to severe encephalopathy: a randomized placebo-controlled trial. This study was done from the perspective of asking if rhEPO by itself in resource poor settings without access to cooling in and of itself could make a difference in outcome for patients with HIE. This was a larger study with 100 Hundred term neonates (37 weeks or greater) with moderate or severe HIE. Fifty were randomized by random permuted block algorithm to receive either rhEPO 500 U kg− 1 per dose IV on alternate days for a total of five doses with the first dose given by 6 h of age (treatment group) or 2 ml of normal saline (50 neonates) similarly for a total of five doses (placebo group) in a double-blind study. The primary outcome was combined end point of death or moderate or severe disability at mean age of 19 months and the results of this and other important outcomes are shown below.
Outcome
Treatment
Placebo
p
Death/disability (mod/severe HIE)
40%
70%
0.003
Death/disability (mod HIE only)
21%
61%
0.004
Cerebral Palsy
23%
45%
0.04
MRI abnormalities
40%
60%
0.04
Seizures treatment at 19 months
19%
43%
0.03
To say that these results are impressive is an understatement. The results are on par with those of cooling’s effect on reduction of injury and improvement in outcome. When looking at the primary outcome alone the result in dramatic when put in perspective of looking at number needed to treat which is 4! This is significant and I can’t help but wonder if the impact of this medication is at least in part related to starting the dosing within the same window of effectiveness of therapeutic hypothermia. Importantly there were no adverse effects noted in the study and given that rhEpo has been used to treat anemia of prematurity in many studies and not found to be associated with any significant side effects I would say this is a fairly safe therapy to use in this setting.
Next Steps
I find this puts us in a challenging position. The academic purists out there will call for larger and well designed studies to test the combination of rhEPO and cooling both initiated within 6 hours of age. While it takes years to get these results might we be missing an opportunity to enhance our outcomes with this combination that is right in front of us. The medication in question other than raising your RBC count has little if any side effects especially when given for such a short duration and by itself and possibly with cooling increases the rate of neuroprotection already. I don’t know about you but I at least will be bringing this forward as a question for my team. The fundamental question is “can we afford to wait?”
This post rings in another new video to add to the series on the All Things Neonatal YouTube channel. I hope that you have gotten something out of the ones posted so far and that this adds something further to your approach to neonatal care.
The Golden Hour Revisited
In the last post to the video selections entitled A Golden Opportunity For Your NICU Team! the main thrust of the video was on the use of the Golden Hour approach to starting a baby on CPAP. Having a standardized checklist based approach to providing care to high risk newborns improves team functioning for sure. What do you do though when you need to hand off a patient to another team? Depending on where you work this may not be an issue if the team performing the resuscitation is the team providing the care for the patient in the NICU. Perhaps you work in a centre similar to our own where the team performing resuscitation is not the same as the one who will ultimately admit the patient. You may also be in a location where there are no babies born on site but rather all patients are transferred in so in each case the patient is new to everyone on the receiving team. How do you ensure that a complete hand over is done.
Out with the old and in with the new!
By no means do I want to imply that it is not possible to transfer information outside of the way that we demonstrate in this video. What I do believe though is that with telehealth being available in more and more settings or without a formal support for the same, the use of smartphones make video conferencing a reality for almost everyone. In most centres handovers have followed the practice of like communicating with like. Nurses give report to nurses, respiratory therapists to each other and MDs to MDs. What if there was another way though? In the video below we demonstrate another approach. Would it work for your team?
As you can tell I am a big fan of simulation in helping to create high functioning teams! More of these videos can be accessed on my Youtube channel at
