How reliable are capillary refill and blood pressure in determination of hemodynamic compromise?

When I think back to my early days as a medical student, one of the first lessons on the physical exam involves checking central and peripheral perfusion as part of the cardiac exam.  In the newborn to assess the hemodynamic status I have often taught that while the blood pressure is a nice number to have it is important to remember that it is a number that is the product of two important factors; resistance and flow.  It is possible then that a newborn with a low blood pressure could have good flow but poor vascular tone (warm shock) or poor flow and increased vascular tone (cardiogenic shock or hypovolemia).  Similarly, the baby with good perfusion could be in septic shock and be vasodilated with good flow.  In other words the use of capillary and blood pressure may not tell you what you really want to know.

Is there a better way?

As I have written about previously, point of care ultrasound is on the rise in Neonatology.  As more trainees are being taught the skill and equipment more readily available opportunities abound for testing various hypotheses about the benefit of such technology.  In addition to my role as a clinical Neonatologist I am also the Medical Director of the Child Health Transport Team and have pondered about a future where ultrasound is taken on retrievals to enhance patient assessment.  I was delighted therefore to see a small but interesting study published on this very topic this past month. Browning Carmo KB and colleagues shared their experience in retrieving 44 infants in their paper Feasibility and utility of portable ultrasound during retrieval of sick preterm infants.  The study amounted to a proof of concept and took 7 years to complete in large part due to the rare availability of staff who were trained in ultrasound to retrieve patients.   These were mostly small higher risk patients (median birthweight, 1130 g (680–1960 g) and median gestation, 27 weeks (23–30)).  Availability of a laptop based ultrasound device made this study possible now that there are nearly palm sized and tablet based ultrasound units this study would be even more feasible now (sometimes they were unable to send a three person team due to weight reasons when factoring in the ultrasound equipment).  Without going into great detail the measurements included cardiac (structural and hemodynamic) & head ultrasounds.  Bringing things full circle it is the hemodynamic assessment that I found the most interesting.

Can we rely on capillary refill?

From previous work normal values for SVC flow are >50 ml/kg/min and for Right ventricular output > 150 ml/kg/min. These thresholds if not met have been correlated with adverse long term outcomes and in the short term need for inotropic support.  In the absence of these ultrasound measurements one would use capillary refill and blood pressure to determine the clinical status but how accurate is it?

First of all out of the 44 patients retrieved, assessment in the field demonstrated 27 (61%) had evidence using these parameters of low systemic blood flow. After admission to the NICU 8 had persistent low systemic blood flow with the patients shown below in the table.  The striking finding (at least to me) is that 6 out of 8 had capillary refill times < 2 seconds.  With respect to blood pressure 5/8 had mean blood pressures that would be considered normal or even elevated despite clearly compromised systemic blood flow.  To answer the question I have posed in this section I think the answer is that capillary refill and I would also add blood pressure are not telling you the whole story.  I suspect in these patients the numbers were masking the true status of the patient.

Screenshot 2017-06-09 11.38.17.png

How safe is transport?

One other aspect of the study which I hope would provide some relief to those of us who transport patients long distance is that the head ultrasound findings before and after transport were unchanged.  Transport with all of it’s movement to and fro and vibrations would not seem to put babies at risk of intracranial bleeding.

 

Where do we go from here?

Before we all jump on the bandwagon and spend a great deal of money buying such equipment it needs to be said “larger studies are needed” looking at such things as IVH.  Although it is reassuring that patients with IVH did not have extension of such bleeding after transport, it needs to be recognized that with such a small study I am not comfortable saying that the case is closed. What I am concerned about though is the lack of correlation between SVC and RVO measurements and the findings we have used for ages to estimate hemodynamic status in patients.

There will be those who resist such change as it does require effort to acquire a new set of skills.  I do see this happening though as we move forward if we want to have the most accurate assessment of clinical status in our patients.  As equipment with high resolution becomes increasingly available at lower price points, how long can we afford not to adapt?

Oh the places you'll go

Oh the places you'll go

It is hard to be a Neonatologist who took the path through Pediatrics first and not use a Dr. Seuss quote from time to time.  e26a79ea-90a6-4d2c-b748-107583da3b3a_1-c8a62a7c18ba4bbc0bcfb40c1c3e4d16.jpegIf your unit is anything like ours where you work I imagine you feel as if you are bursting at the seams.  As the population grows so do our patient volumes.  I often quote the number 10% as being the number of patients we see out of all deliveries each year in our units.  When I am asked why our numbers are so high I counter that the answer is simple.  For every extra 100 births we get 10 admissions. It is easy though to get lost in the chaos of managing a unit in such busy times and not take a moment to look back and see how far we have come.  What did life look like 30 years ago or 25 years ago?  In Winnipeg, we are preparing to make a big move into a beautiful new facility in 2018. This will see us unify three units into one which is no easy task but will mean a capacity of 60 beds compared to the 55 operational beds we have at the moment.

In 2017 we are routinely resuscitating infants as young as 23 weeks and now with weights under 500g at times.  Whereas in the past anyone under 1000g was considered quite high risk, now the anticipated survival for a 28 week infant at 1000g is at or above 95%.  Even in my short career which began in 1998 in terms of Pediatrics and then 2001 in Neonatology our approach in terms of comfort with the smallest infants has eased greatly.  What inspired this post though was a series of newspaper clippings from 1986 and 1991 that made me take a moment to look up at the sky and mutter “huh”.  When you take a trip down memory lane and read these posts I think you will agree we have come a LONG way and (in truth) in a very short time.

1986 – Opening of the New NICU at Children’s Hospital

Newspaper clipping

This unit was built with 3.5 million dollars.  Imagine how far that would go now…

The unit had a capacity of 18 beds but opened with only 12 and a nursing staff of 60 (compare that to 150 now!).  They couldn’t open more beds due to the lack of available nurses with sufficient skills.

My favourite comment to provide some perspective was that 5 to 10 years before this time the estimated survival for infants under 1000g was 15%!

Have we ever come a long way in family centred care.  Can you imagine having a baby born now at 695g whose family wouldn’t get to hold them till almost 3.5 months of age?!  That is what happened in the case described in this article.

1991 – Opening of the new Intermediate Care Nursery

Chronicle page 1Chronicle page 2

Did you know the old unit had 19 beds (was originally 9 babies) and expanded to 27 at this time?

It cost 3.1 million to build this unit.

The long and the short of it is that yes things are busy and in fact busier than they have ever been.  Do not lose sight however wherever your practice is that you are part of a story for the ages.  Things that were once thought impossible or miracles are now everyday events and you have been part of it.  For those of you who read this post this will likely bring about a lot of nostalgia for you.  Thirty years in medicine is not a long time and we have accomplished so much along the way.  For those of you who are just starting out, imagine where we will be in 30 years from now.  I for one can’t wait to read about it and wonder where we will have gone by then.

 

Communication is certainly key

If there is one thing that keeps coming back as a lesson again and again in life it is the importance of communication.  Whether it be in the home or at work, too many of our “problems” in the workplace come down to whether or not our teams talk to one another effectively.

A tremendous source of stress of course is the unknown. When a baby is born in the field we can only rely on the information being presented to us via telephone contact.  In the melee that occurs on arrival of a potentially sick patient, details can be missed.

The following video illustrates such a situation and I believe aptly provides a good example of how to communicate in such a way that the stress of the situation is relieved. If we can all strive to slow things down just a little we may find that communication eliminates much of the tension in such a situation.

If you are looking to “slow” down your life and improve things such as communication style you may want to have a look at the book “In Praise of Slow” as we head into the weekend.  It’s all about slowing things down to actually improve efficiency.  The world is moving pretty quickly these days and couldn’t we all do with a little more efficiency and less wasted time?  In Neonatology we are confronted with surprises every day, often with little notice.  If we can slow things down and pass on the needed information to the right people at the right time we will help to reduce errors if we can just get it right the first time!

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

All Things Neonatal YouTube

To receive regular updates as new videos are added feel free to subscribe!

Lastly a big thank you to NS, RH and GS without whom none of this would have been possible!

Is epinephrine via the ETT really so bad?

Is epinephrine via the ETT really so bad?

 

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.

 

 

A Leap Forward in the Treatment of HIE?

A Leap Forward in the Treatment of HIE?

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?”

 

 

A Golden Opportunity For Your NICU Team!

I have written about respectful communication before in Kill them with kindness.

The importance of collaborating in a respectful manner cannot be overemphasized, as a calm and well prepared team can handle just about anything thrown their way.  This past week I finally had the opportunity to take the 7th ed NRP instructor course.  What struck me most about the new version of the course was not the approach to the actual resuscitation but the preparation that was emphasized before you even start!  It only takes 30 seconds to establish who is doing what in a resuscitation and while it would seem logical to divide up the roles each will take on it is something that has not been consistently done (at least in our institution).  When a baby is born and responds to PPV quickly, this may not seem that important but in a situation where a team is performing chest compressions, placing an emergency UVC and moving on to epinephrine administration it certainly is nice to know in advance who is doing what.

The Golden Hour

We and many other centres have adopted this approach to resuscitation and at least here developed a checklist to ensure that everyone is prepared for a high risk delivery.  While teams may think they have all the bases covered, when heart rates are racing it may surprise you to see how many times crucial bits of information or planning is missed.  As I told you in another post I will be releasing a series of videos that I hope others will find useful.  The video in this case is of a team readying itself for the delivery of a preterm infant that they anticipate will have respiratory distress.  Ask yourself as you watch the film whether your team is preparing to this degree or not.  Preparing in such a fashion certainly reduces the risk of errors caused by assumptions about who is doing what or what risk factors are present.

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

All Things Neonatal YouTube

To receive regular updates as new videos are added feel free to subscribe!

Lastly a big thank you to NS, RH and GS without whom none of this would have been possible!