It is hard to believe but it has been almost 3 years since I wrote a piece entitled A 200 year old invention that remains king of all tech in newborn resuscitation. In the post I shared a recent story of a situation in which the EKG leads told a different story that what our ears and fingers would want us to believe. The concept of the piece was that in the setting of pulseless electrical activity (where there is electrical conductance in the myocardium but lack of contraction leaves no blood flow to the body) one could pick up a signal from the EKG leads when there is in fact no pulse or perfusion to vital organs. This single experience led me to postulate that this situation may be more common than we think and the application of EKG leads routinely could lead to errors in decision making during resuscitation of the newborn. It is easy to see how that could occur when you think about the racing pulses of our own in such situations and once chest compressions start one might watch the monitor and forget when they see a heart rate of 70 BPM to check for a corresponding pulse or listen with the stethoscope. I could see for example someone stopping chest compressions and continuing to provide BVM ventilation despite no palpable pulse when they see the QRS complex clearly on the monitor. I didn’t really have much evidence to support this concern but perhaps there is a little more to present now.
A Crafty Animal Study Provides The Evidence
I haven’t presented many animal studies but this one is fairly simple and serves to illustrate the concern in a research model. For those of you who haven’t done animal research, my apologies in advance as you read what happened to this group of piglets. Although it may sound awful, the study has demonstrated that the concern I and others have has is real.
For this study 54 newborn piglets (equivalent to 36-38 weeks GA in humans) were anesthetized and had a flow sensor surgically placed around the carotid artery. ECG leads were placed as well and then after achieving stabilization, hypoxia was induced with an FiO2 of 0.1 and then asphyxia by disconnecting the ventilator and clamping the ETT. By having a flow probe around the carotid artery the researchers were able to determine the point of no cardiac output and simultaneously monitor for electrical activity via the EKG leads. Auscultation for heart sounds was performed as well.
The results essentially confirm why I have been concerned with an over reliance on EKG leads.
Of the 57 piglets, 14 had asystole and no carotid flow but in 23 there was still a heart rate present on the EKG with no detectable carotid flow. This yields a sensitivity of only 37%. Moreover, the overall accuracy of the ECG was only 56%.
Meanwhile the stethoscope which I have referred to previously as the “king” in these situations had 100% sensitivity so remains deserving of that title.
What do we do with such information?
I think the results give us reason to pause and remember that faster isn’t always better. Previous research has shown that signal acquisition with EKG leads is faster than with oximetry. While a low heart rate detected quickly is helpful to know what the state of the infant is and begin the NRP pathway, we simply can’t rely on the EKG to tell us the whole story. We work in interdisciplinary teams and need to support one another in resuscitations and provide the team with the necessary information to perform well. The next time you are in such a situation remember that the EKG is only one part of the story and that auscultation for heart sounds and palpation of the umbilical cord for pulsation are necessary steps to demonstrate conclusively that you don’t just have a rhythm but a perfusing one.
I would like to thank the Edmonton group for continuing to put out such important work in the field of resuscitation!
Hi, my name is Diane Schultz and Michael has asked me to write a series of posts on his blog about Kangaroo Care (KC). Seeing as I am one of the Champions (they call you that, but sometimes the word begins with a B) for KC in my unit, I was thrilled. I thought I would begin with an introduction as to why I want to write about this.
I have been a Neonatal Nurse for 29 years working in the NICU at St. Boniface Hospital in Winnipeg. I felt that I had always given good care to the families but did not really make connections with them.
I was fortunate enough to meet Dr. Susie Ludington about 10 years ago at an Academy of Neonatal Nursing conference. She was a general session presenter and was speaking about Kangaroo Care. The first thing she said was “My goal is Kangaroo Care 24/7”. All I could think of was WTF!? I would have to listen to this Nutbar for an hour? Our unit had been doing KC for years but only occasionally and usually the parent would ask for it, we certainly did not promote it or do it with our more fragile infants.
After listening to Dr. Ludington present, my world changed. What she said hit a cord; she presented benefit after benefit with rationale and evidence that made complete sense to me. I felt guilty I had not been doing this at work and guilty that I had not held my own daughters this way. I am now lucky to be able to call Dr. Ludington a friend, and know she has changed my life.
Now, there is a lot of evidence out there touting the benefits of KC, but the real way to understand and believe in it is to do it. KC creates its own evidence. Every time I bring out a medically fragile infant to be held in KC, I know that this is the right place for that infant to be: with their parent being held. You can see the relaxation on all of their faces (decreasing cortisol), the infant is able to go into a deep sleep (promotes brain maturation), and the family is able to connect in the best way possible. I feel KC is as important as anything else we do at the bedside and is an extremely necessary therapy.
Promoting KC in my unit has benefited me at so many levels; I believe it has actually saved my career and given me a focus that I didn’t have before. You can’t help but make connections with your families, and these families are able to make connections with their little ones. KC is also a very important part of Family Integrated Care, as this is something that the family can contribute to their child’s care.
I also couldn’t be more proud of my unit; the staff I have the pleasure to work with are some of the best health care professionals around. They make every effort to bring our fragile infants out for KC and it has become part of our culture in our NICU. KC happens in our unit with almost all of our infants, the only exceptions being actively cooling babies and infants with chest tubes. We have also created a Standard Work Protocol so all medically fragile infants come out the safest way possible without creating extra stress on the infant or family.
In my series of posts I will present the many benefits of KC for infants and their families and share some of my experiences. I hope you will be able to take something away from this, begin to try KC in your own unit, and create your own evidence.
In the first part of this series of posts called Can prophylactic dextrose gel prevent babies from becoming hypoglycemic? the results appeared to be a little lackluster. The study that this blog post was based on was not perfect and the lack of a randomized design left the study open to criticism and an unbalancing of risks for hypoglycemia. Given these faults it is no doubt that you likely didn’t run anywhere to suggest we should start using this right away as a protocol in your unit.
Dosing was given either once at 1 h of age (0.5 ml/kg or 1 ml/kg) or three more times (0.5 ml/kg) before feeds in the first 12 h, but not more frequently than every 3 h. Each dose of gel was followed by a breastfeed. The groups given prophylaxis fell into the following risk categories;
IDM (any type of diabetes), late preterm (35 or 36 wk gestation), SGA (BW < 10th centile or < 2.5 kg), LBW (birthweight > 90th centile or > 4.5 kg), maternal use of β-blockers.
Blood glucose was measured at 2 h of age and then AC feeds every 2 to 4 h for at least the first 12 h. This was continued until an infant had 3 consecutive blood glucose concentrations of 2.6 mmmol/L. With a primary outcome of hypoglycemia in the first 48 hours their power calculation dictated that a total sample size of 415 babies (66 in each treatment arm, 33 in each placebo arm) was needed which thankfully they achieved which means we can believe the results if they found no difference!
What did they find?
One might think that multiple doses and/or higher doses of glucose gel would be better than one dose but curiously they found that the tried and true single dose of 0.5 mL/kg X 1 offered the best result. “Babies randomised to any dose of dextrose gel were less likely to develop hypoglycaemia than those randomised to placebo (RR 0.79, 95% CI 0.64–0.98, p = 0.03; number needed to 10.”
Looking at the different cumulative doses, the only dosing with a 95% confidence interval that does not cross 1 was the single dosing. Higher and longer dosing showed no statistical difference in the likelihood of becoming hypoglycemic in the first 48 hours. As was found in the sugar babies study, admission to NICU was no different between groups and in this study as with the sugar baby study if one looked at hypoglycemia as a cause for admission there was a slight benefit. Curiously, while the previous study suggested a benefit to the rate of breastfeeding after discharge this was not noted here.
How might we interpret these results?
The randomized nature of this study compared to the one reviewed in part I leads me to trust these findings a little more than the previous paper. What this confirms in my mind is that giving glucose gel prophylaxis to at risk infants likely prevents hypoglycemia in some at risk infants and given that there were no significant adverse events (other than messiness of administration), this may be a strategy that some units wish to try out. When a low blood glucose did occur it was later in the group randomized to glucose gel at a little over 3 hours instead of 2 hours. The fact that higher or multiple dosing of glucose gel given prophylactically didn’t work leads me to speculate this may be due to a surge of insulin. Giving multiple doses or higher doses may trigger a normal response of insulin in a baby not at risk of hypoglycemia but in others who might already have a high baseline production of insulin such as in IDMs this surge might lead to hypoglycemia. This also reinforces the thought that multiple doses of glucose gel in babies with hypoglycemia should be avoided as one may just drive insulin production and the treatment may become counterproductive.
In the end, I think these two papers provide some food for thought. Does it make sense to provide glucose gel before a problem occurs? We already try and feed at risk babies before 2 hours so would the glucose gel provide an added kick or just delay the finding of hypoglycemia to a later point. One dose may do the trick though.
A reader of my Facebook page sent me a picture of the hPOD trial which is underway which I hope will definitively put this question to rest. For more on the trial you can watch Dr. Harding speak about the trial here.
I have written a number of times already on the topic of dextrose gels. Previous posts have largely focused on the positive impacts of reduction in NICU admissions, better breastfeeding rates and comparable outcomes for development into childhood when these gels are used. The papers thus far have looked at the effectiveness of gel in patients who have become hypoglycemic and are in need of treatment. The question then remains as to whether it would be possible to provide dextrose gel to infants who are deemed to be at risk of hypoglycemia to see if we could reduce the number of patients who ultimately do become so and require admission.
Answering that question
Recently, Coors et al published Prophylactic Dextrose Gel Does Not Prevent Neonatal Hypoglycemia: A Quasi-Experimental Pilot Study. What they mean by Quasi-Experimental is that due to availability of researchers at off hours to obtain consent they were unable to produce a randomized controlled trial. What they were able to do was compare a group that had the following risk factors (late preterm, birth weight <2500 or >4000 g, and infants of mothers with diabetes) that they obtained consent for giving dextrose gel following a feed to a control group that had the same risk factors but no consent for participation. The protocol was that each infant would be offered a breastfeed or formula feed after birth followed by 40% dextrose gel (instaglucose) and then get a POC glucose measurement 30 minutes later. A protocol was then used based on different glucose results to determine whether the next step would be a repeat attempt with feeding and gel or if an IV was needed to resolve the issue.
To be sure, there was big hope in this study as imagine if you could prevent a patient from becoming hypoglycemic and requiring IV dextrose followed by admission to a unit. Sadly though what they found was absolutely no impact of such a strategy. Compared with the control group there was no difference in capillary glucose after provision of dextrose gel (52.1 ± 17.1 vs 50.5 ± 15.3 mg/dL, P = .69). One might speculate that this is because there are differing driving forces for hypoglycemia and indeed that was the case here where there were more IDMs and earlier GA in the prophylactic group. On the other hand there were more LGA infants in the control group which might put them at higher risk. When these factors were analyzed though to determine whether they played a role in the lack of results they were found not to. Moreover, looking at rates of admission to the NICU for hypoglycemia there were also no benefits shown. Some benefits were seen in breastfeeding duration and a reduction in formula volumes consistent with previous studies examining the effect of glucose gel on both which is a win I suppose.
It may also be that when you take a large group of babies with risks for hypoglycemia but many were never going to become hypoglycemic, those who would have had a normal sugar anyway dilute out any effect. These infants have a retained ability to produce insulin in response to a rising blood glucose and to limit the upward movement of their glucose levels. As such what if the following example is at work? Let’s say there are 200 babies who have risk factors for hypoglycemia and half get glucose gel. Of the 100 about 20% will actually go on to have a low blood sugar after birth. What if there is a 50% reduction in this group of low blood sugars so that only 10 develop low blood glucose instead of 20. When you look at the results you would find in the prophylaxis group 10/100 babies have a low blood sugar vs 20/100. This might not be enough of a sample size to demonstrate a difference as the babies who were destined not to have hypoglycemia dilute out the effect. A crude example for sure but when the incidence of the problem is low, such effects may be lost.
A Tale of Two Papers
This post is actually part of a series with this being part 1. Part 2 will look at a study that came up with a different conclusion. How can two papers asking the same question come up with different answers? That is the story of medicine but in the next part we will look at a paper that suggests this strategy does work and look at possible reasons why.
“Recognizing that delivery and time of discharge practices vary across Canada, the timing of testing should be individualized for each centre and (ideally) occur after 24 hours postbirth to lower FP results. And because the intent is to screen newborns before they develop symptoms, the goal should be to perform screening before they reach 36 hours of age.”
This recommendation was put in place to minimize the number of false positive results and prevent Pediatricians and Cardiologists nationwide from being inundated with requests to rule out CCHD as earlier testing may pick up other causes for low oxygen saturation such as TTN. The issue remains though that many patients are indeed discharged before 24 hours and in the case of midwife deliveries either in centres or in the home what do we do?
A Population Study From the Netherlands May Be of Help Here
Researchers in the Netherlands had a golden opportunity to answer this question as a significant proportion of births occur there in the home under the care of a midwife. Accuracy of Pulse Oximetry Screening for Critical Congenital Heart Defects after Home Birth and Early Postnatal Discharge by Ilona C. Narayen et al was published this month in J Peds. About 30% of births are cared for by a midwife with about 20% occurring in the home. The authors chose to study this population of infants who were all above 35 weeks gestation and not admitted to an intensive care nor had suspicion of CCHD prior to delivery. The timing of the screening was altered from the typical 24-48 hours to be two time points to be more reflective of midwives practice. All patients were recruited after birth with the use of information pamphlets. The prospective protocol was screening on 2 separate moments: on day 1, at least 1 hour after birth, and on day 2 or 3 of life. The criteria for passing or failing the test are the same as those outlined in the CPS practice point. As part of the study, patients with known CCHDs were also screened separately as a different group to determine the accuracy of the screening test in patients with known CCHD.
There were nearly 24000 patients born during this period. Only 49 cases of CCHD were identified by screening and of these 36 had been picked up antenatally giving a detection rate of 73%. Out of 10 patients without prenatal diagnosis who also had saturation results available the detection rate was 50%. Three of the misses were coarctation of the aorta (most likely diagnosis to be missed in other studies), pulmonary stenosis (this one surprises me) and TGA (really surprises me). The false-positive rate of pulse oximetry screening (no CCHD) was 0.92%. The specificity was over 99% meaning that if you didn’t have CCHD you were very likely to have a negative test. Not surprisingly, most false- positives occurred on day 1 (190 on day 1 vs 31 infants on day 2 or 3). There were five patients missed who were not detected either by antenatal ultrasound. These 5 negatives ultimately presented with symptoms at later time points and all but one survived (TGA) so out of 24000 births the system for detecting CCHD did reasonably well in enhancing detection as they picked up another 5 babies that had been missed antenatally narrowing the undetected from 10 down to 5.
Perhaps the most interesting thing about the study though is what they also found. As the authors state: “Importantly, 61% (134/221) of the infants with false-positive screenings proved to have significant noncardiac illnesses re- quiring intervention and medical follow-up, including infection/ sepsis (n = 31) and PPHN or transient tachypnea of the newborn (n = 88)”
There are certainly detractors of this screening approach but remember these infants were all thought to be asymptomatic. By implementing the screening program there was opportunity to potentially address infants care needs before they went on to develop more significant illness. Under appreciated TTN could lead to hypoxia and worsen and PPHN could become significantly worse as well. I think it is time to think of screening in this way as being more general and not just about finding CCHD. It is a means to identify children with CCHD OR RESPIRATORY illnesses earlier in their course and do something about it!