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The days of the Apgar score may be numbered

AllThingsNeonatal

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The days of the Apgar score may be numbered

One of the first things a student of any discipline caring for newborns is how to calculate the apgar score at birth.  Over 60 years ago Virginia Apgar created this score as a means of giving care providers a consistent snapshot of what an infant was like in the first minute then fifth and if needed 10, 15 and so on if resuscitation was ongoing.  For sure it has served a useful purpose as an apgar score of 0 and 0 gives one cause for real worry.  What about a baby with an apgar of 3 and 7 or 4 and 8?  There are certainly infants who have done very well who initially had low apgar scores and conversely those who had higher apgar scores who have had very significant deleterious outcomes including death.  I don’t mean to suggest that the apgar scores don’t provide any useful predictive value as they are used as part of the criteria to determine if a baby merits whole body cooling or not.  The question is though after 60+ years, has another score been created to provide similar information but enhance the predictive value derived from a score?

The Neonatal Resuscitation and Adaptation Score (NRAS)

Back in 2015 Jurdi et al published  Evaluation of a Comprehensive Delivery Room Neonatal Resuscitation and Adaptation Score (NRAS) Compared to the Apgar Score.  This new score added into a ten point score resuscitative actions taken at the 1 and 5 minute time points to create a more functional score that included interventions.  The other thing this new score addressed was more recent data that indicated a blue baby at birth is normal (which is why we have eliminated asking the question “is the baby pink?” in NRP.  Knowing that, the colour of the baby in the apgar score may not really be that relevant.  Take for example a baby with an apgar score of 3 at one minute who could have a HR over 100 and be limp, blue and with shallow breathing.  Such a baby might get a few positive pressure breaths and then within 10 seconds be breathing quite well and crying.  Conversely, they might be getting ongoing PPV for several minutes and need oxygen.  Were they also getting chest compressions?  If I only told you the apgar score you wouldn’t have much to go on.  Now look at the NRAS and compare the information gathered using two cardiovascular (C1&2), one neurological test (N1) and two respiratory assessments (R1&2).

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The authors in this study performed a pilot study on only on 17 patients really as a proof of concept that the score could be taught and implemented.  Providers reported both scores and found “superior interrater reliability (P < .001) and respiratory component reliability (P < .001) for all gestational ages compared to the Apgar score.”

 

A Bigger Study Was Needed

The same group in 2018 this time led by Witcher published Neonatal Resuscitation and Adaptation Score vs Apgar: newborn assessment and predictive ability.  The primary outcome was the ability of a low score to predict mortality with a study design that was a non-inferiority trial.  All attended deliveries were meant to have both scores done but due to limited numbers of trained personnel who could appropriately administer both scores just under 90% of the total deliveries were assigned scores for comparison.  The authors sought to recruit 450 infants to show that a low NRAS score (0–3) would not be inferior to a similar Apgar at predicting death.  Interestingly an interim analysis found the NRAS to be superior to Apgar when 75.5% of the 450 were enrolled, so the study was stopped.  What led the apgar score to perform poorly in predicting mortality (there were only 12 deaths though in the cohort) was the fact that 49 patients with a 1 minute apgar score of 0-3 survived compared to only 7 infants with a low NRAS score.

The other interesting finding was the ability of the NRAS to predict the need for respiratory support at 48 hours with a one minute apgar score of 0-3 being found in 39% of those on support compared to 100% of those with a low NRAS.  Also at 5 minutes a score of 4-6 for the apgar was found in 48% of those with respiratory support at 48 hours vs 87% of those with a similar range NRAS.  These findings were statistically significant while a host of other conditions such as sepsis, hypoglycemia, hypothermia and others were no different in terms of predictive ability of the scores.

An Even Bigger Study is Needed

To be sure, this study is still small and missed just over 90% of all deliveries so it is possible there is some bias that is not being detected here.  I do think there is something here though which a bigger study that has an army of people equipped to provide the scoring will add to this ongoing story.  Every practitioner who resuscitates an infant is asked at some point in those first minutes to hour “will my baby be ok?”.  The truth is that the apgar score has never lived up to the hope that it would help us provide an accurate clairvoyant picture of what lies ahead for an infant.   Where this score gives me hope is that a score which would at the very least help me predict whether an infant would likely still be needing respiratory support in 48 hours provides the basic answer to the most common question we get in the unit once admitted; “when can I take my baby home”.  Using this score I could respond with some greater confidence in saying “I think your infant will be on support for at least 48 hours”.  The bigger question though which thankfully we don’t have to address too often for the sickest babies at birth is “will my baby survive?”.  If a larger study demonstrates this score to provide a greater degree of accuracy then the “Tipping Point” might just be that to switching over to the NRAS and leaving the apgar score behind.  That will never happen overnight but medicine is always evolving and with time you the reader may find yourself becoming very familiar with this score!

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The first study I did many years ago with one of my students was a trial to replace apgar score cause I was Always convinced it is not adapted to prematures. At the end of the study, I found some interesting elements to measure but it didn't make up a score ! You gave me ideas;  why not combine some variables from my study to some from the NRAS score to create a new clinical score. The NRAS is not purely clinical like Apgar but very interesting.

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Sería muy bueno que en todas partes pudiésemos medir los dos puntajes simultáneamente, ya que no se necesita de una inversión muy alta y, en cambio, la información conseguida sería muy abundante y proporcionaría mucha evidencia

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