It has been over two years since I have written on this subject and it continues to be something that I get excited about whenever a publication comes my way on the topic. The last time I looked at this topic it was after the publication of a randomized trial comparing in which one arm was provided automated FiO2 adjustments while on ventilatory support and the other by manual change. Automated adjustments of FiO2. Ready for prime time? In this post I concluded that the technology was promising but like many new strategies needed to be proven in the real world. The study that the post was based on examined a 24 hour period and while the results were indeed impressive it left one wondering whether longer periods of use would demonstrate the same results. Moreover, one also has to be wary of the Hawthorne Effect whereby the results during a study may be improved simply by being part of a study.
The Real World Demonstration
So the same group decided to look at this again but in this case did a before and after comparison. The study looked at a group of preterm infants under 30 weeks gestational age born from May – August 2015 and compared them to August to January 2016. The change in practice with the implementation of the CLiO2 system with the Avea ventilator occurred in August which allowed two groups to be looked at over a relatively short period of time with staff that would have seen little change before and after. The study in question is by Van Zanten HA The effect of implementing an automated oxygen control on oxygen saturation in preterm infants. For the study the target range of FiO2 for both time periods was 90 – 95% and the primary outcome was the percentage of time spent in this range. Secondary outcomes included time with FiO2 at > 95% (Hyperoxemia) and < 90, <85 and < 80% (hypoxemia). Data were collected when infants received respiratory support by the AVEA and onlyincluded for analysis when supplemental oxygen was given, until the infants reached a GA of 32 weeks
As you might expect since a computer was controlling the FiO2 using a feedback loop from the saturation monitor it would be a little more accurate and immediate in manipulating FiO2 than a bedside nurse who has many other tasks to manage during the care of an infant. As such the median saturation was right in the middle of the range at 93% when automated and 94% when manual control was used. Not much difference there but as was seen in the shorter 24 hour study, the distribution around the median was tighter with automation. Specifically with respect to ranges, hyperoxemia and hypoxemia the following was noted (first number is manual and second comparison automated in each case).
Time spent in target range: 48.4 (41.5–56.4)% vs 61.9 (48.5–72.3)%; p<0.01
Hyperoxemia >95%: 41.9 (30.6–49.4)% vs 19.3 (11.5–24.5)%; p<0.001
< 90%: 8.6 (7.2–11.7)% vs 15.1 (14.0–21.1)%;p<0.0001
< 85%: 2.7 (1.4–4.0)% vs 3.2 (1.8–5.1)%; ns
Hypoxemia < 80%: 1.1 (0.4–1.7)% vs 0.9 (0.5–2.1)%; ns
What does it all mean?
I find it quite interesting that while hyperoxemia is reduced, the incidence of saturations under 90% is increased with automation. I suspect the answer to this lies in the algorithmic control of the FiO2. With manual control the person at the bedside may turn up a patient (and leave them there a little while) who in particular has quite labile saturations which might explain the tendency towards higher oxygen saturations. This would have the effect of shifting the curve upwards and likely explains in part why the oxygen saturation median is slightly higher with manual control. With the algorithm in the CLiO2 there is likely a tendency to respond more gradually to changes in oxygen saturation so as not to overshoot and hyperoxygenate the patient. For a patient with labile oxygen saturations this would have a similar effect on the bottom end of the range such that patients might be expected to drift a little lower then the target of 90% as the automation corrects for the downward trend. This is supported by the fact that when you look at what is causing the increase in percentage of time below 90% it really is the category of 85-89%.
Is this safe? There will no doubt be people reading this that see the last line and immediately have flashbacks to the SUPPORT trial which created a great deal of stress in the scientific community when the patients in the 85-89% arm of the trial experienced higher than expected mortality. It remains unclear what the cause of this increased mortality was and in truth in our own unit we accept 88 – 92% as an acceptable range. I have no doubt there are units that in an attempt to lessen the rate of ROP may allow saturations to drop as low as 85% so I continue to think this strategy of using automation is a viable one.
For now the issue is one of a ventilator that is capable of doing this. If not for the ventilated patient at least for patients on CPAP. In our centre we don’t use the Avea model so that system is out. With the system we use for ventilation there is also no option. We are anxiously awaiting the availability of an automated system for our CPAP device. I hope to be able to share our own experience positively when that comes to the market. From my standpoint there is enough to do at the bedside. Having a reliable system to control the FiO2 and minimize oxidative stress is something that may make a real difference for the babies we care for and is something I am eager to see.
As someone with an interest in neonatal abstinence (NAS) I am surprised that I missed this study back in May. Anyone who says they aren’t interested in NAS research must be turning a blind eye to the North American epidemic of patients filling neonatal units or postpartum wards in need of treatment for the same. News feeds such as CNN have covered this story many times with concerning articles such as this published “Opioid Crisis Fast Facts” even the Trump White House has officially declared it as an emergency at this point. With NICU resources stretched and care providers fatigue levels wearing thin (these patients are typically very challenging to take care of due to the crying and agitation with neurological excitability that is at the core of the symptoms, something needs to be done. The vast majority of neonatal care providers treat such patients with an approach that promotes first non pharmacologic strategies such as keeping mom and baby together when possible, breast feeding and disturbing these infants as little as possible to name a few points. For those patients though who require pharmacologic support though, the mainstay has been oral morphine. At least in our units though once a patient is admitted and undergoes treatment we are still looking at anywhere from 3-4 weeks on average that they will occupy a hospital bed. If only there was a better way.
Could Buprenorphine do the trick?
While morphine is widely used to treat NAS symptoms unresponsive to other non pharmacologic methods of control, buprenorphine has a similar profile as an opioid but has less risk of respiratory depression as a partial agonist. A small but important trial has been published directly comparing the use of morphine to buprenorphine for treatment of NAS symptoms with the primary outcome being days of treatment and the second important point being length of stay. The trial, Buprenorphine for the Treatment of the Neonatal Abstinence Syndrome.by Kraft WK et al was entitled the BBORN trial for short. This was a single centre trial in which a double blind/double dummy approach was used. By double dummy this meant that after randomization those babies randomized to morphine received morphine plus a buprenorphine placebo and the other arm received a buprenorphine dose and a morphine placebo. In total 33 infants were randomized to buprenorphine and 30 to morphine (hence my comment about this being a small study). Their power calculation had called for 40 infants per arm to detect a 28% difference in the primary end point of duration of treatment but in the end that didn’t matter so much as they found a significant difference exceeding their estimate anyway. A lack of power would have become important mind you had they not found a difference as they wouldn’t have actually had the numbers to do so.
A strength of the study up front was that all care providers scored NAS symptoms the same way (need to take into account there is some subjectivity in scoring altogether though) and escalations and decreases of medication were done following a strict protocol both ways. In both arms, once a maximal dose of 60 mcg/kg of body weight for buprenorphine and 1.2 mg/kg for morphine was reached phenobarbital was added. When comparing the two groups at the outset there were no significant differences in characteristics so two generally similar populations of infants were being treated.
The Results Were Indeed Impressive
Before launching into the table, there were 21 babies in both groups that were bottle fed and 12 in the burprenorphine group and 9 in the morphine group that breastfed.
|Median days of treatment
|Hospital stay in days
No difference was seen in those who needed phenobarbital. Looking at the table, a couple things really stand out to me. They were looking for a 28% reduction in days of treatment. The results came in far excess of that at a 46% reduction. Curiously, breastfeeding which has classically been associated with a reduction in scores and therefore faster weaning due to less symptoms seemed to have the opposite effect here. Does this imply that breastfeeding slows down both duration of treatment and length of stay as a result? With a study this small it is difficult to say with so few breastfed babies but if I had to guess I would suggest those mothers that worked at breastfeeding may have had longer stays.
Should we all jump on the buprenorphine train?
For now I would give this a big maybe. One of the concerns about burprenorphine is that it comes as a solution of 30% alcohol. Giving multiple doses (3 per day in this study) of such a solution could in part contribute to these results of lower NAS symptoms. Is giving alcohol to reduce symptoms a good idea here? Not sure if there are any long term effects and moreover if the cumulative dose of this medication would be of a concern. Definitely something to check with your local pharmacist before rolling this out. On the other hand if the dose of alcohol provided was truly significant I might have expected the burprenorphine group to be poorer feeders due to intoxication which we certainly did not see.
With increasing volumes of newborns afflicted with symptoms of NAS we do need to find a way to stem the tide. Ideally, primary preventative strategies would be best but until that solution is found could burprenorphine be the next step in tackling this epidemic?
We can always learn and we can always do better. At least that is something that I believe in. In our approach to resuscitating newborns one simple rule is clear. Fluid must be replaced by air after birth and the way to oxygenate and remove CO2 is to establish a functional residual capacity. The functional residual capacity is the volume of air left in the lung after a tidal volume of air is expelled in a spontaneously breathing infant and is shown in the figure. Traditionally, to establish this volume in a newborn who is apneic, you begin PPV or in the spontaneously breathing baby with respiratory distress provide CPAP to help inflate the lungs and establish FRC.
Is there another way?
Something that has been discussed now for some time and was commented on in the most recent version of NRP was the concept of using sustained inflation (SI) to achieve FRC. I have written about this topic previously and came to a conclusion that it wasn’t quite ready for prime time yet in the piece Is It Time To Use Sustained Lung Inflation In NRP?
The conclusion as well in the NRP textbook was the following:
“There are insufficient data regarding short and long-term safety and the most appropriate duration and pressure of inflation to support routine application of sustained inflation of greater than 5 seconds’ duration to the transitioning newborn (Class IIb, LOE B-R). Further studies using carefully designed protocols are needed”
So what now could be causing me to revisit this concept? I will be frank and admit that whenever I see research out of my old unit in Edmonton I feel compelled to read it and this time was no different. The Edmonton group continues to do wonderful work in the area of resuscitation and expand the body of literature in such areas as sustained inflation.
Can you predict how much of a sustained inflation is needed?
This is the crux of a recent study using end tidal CO2 measurement to determine whether the lung has indeed established an FRC or not. Dr. Schmolzer’s group in their paper (Using exhaled CO2 to guide initial respiratory support at birth: a randomised controlled trial) used end tidal CO2 levels above 20 mmHg to indicate that FRC had been established. If you have less CO2 being released the concept would be that the lung is actually not open. There are some important numbers in this study that need to be acknowledged. The first is the population that they looked at which were infants under 32 6/7 weeks and the second is the incidence of BPD (need for O2 or respiratory support at 36 weeks) which in their unit was 49%. This is a BIG number as in comparison for infants under 1500g our own local incidence is about 11%. If you were to add larger infants closer to 33 weeks our number would be lower due to dilution. With such a large number though in Edmonton it allowed them to shoot for a 40% reduction in BPD (50% down to 30%). To accomplish this they needed 93 infants in each group to show a difference this big.
So what did they do?
For this study they divided the groups in two when the infant wouldn’t breathe in the delivery room. The SI group received a PIP of 24 using a T-piece resuscitator for an initial 20 seconds. If the pCO2 as measured by the ETCO2 remained less than 20 they received an additional 10 seconds of SI. In the PPV group after 30 seconds of PPV the infants received an increase of PIP if pCO2 remained below 20 or a decrease in PIP if above 20. In both arms after this phase of the study NRP was then followed as per usual guidelines.
The results though just didn’t come through for the primary outcome although ventilation did show a difference.
|Duration of mechanical ventilation (hrs)
The reduction in hours of ventilation was impressive although no difference in BPD was seen. The problem though with all of this is what happened after recruitment into the study. Although they started with many more patients than they needed, by the end they had only 76 in the SI group and 86 in the PPV group. Why is this a problem? If you have less patients than you needed based on the power calculation then you actually didn’t have enough patients enrolled to show a difference. The additional compounding fact here is that of the Hawthorne Effect. Simply put, patients who are in a study tend to do better by being in a study. The observed rate of BPD was 33% during the study. If the observed rate is lower than expected when the power calculation was done it means that the number needed to show a difference was even larger than the amount they originally thought was needed. In the end they just didn’t have the numbers to show a difference so there isn’t much to conclude.
What I do like though
I have a feeling or a hunch that with a larger sample size there could be something here. Using end tidal pCO2 to determine if the lung is open is in and of itself I believe a strategy to consider whether giving PPV or one day SI. We already use colorimetric devices to determine ETT placement but using a quantitative measure to ascertain the extent of open lung seems promising to me. I for one look forward to the continued work of the Neonatal Resuscitation–Stabilization–Triage team (RST team) and congratulate them on the great work that they continue doing.
Exclusive human milk (EHM) diets using either mother’s own milk or donor milk plus a human based human milk fortifier have been the subject of many papers over the last few years. Such papers have demonstrated reductions is such outcomes as NEC, length of stay, days of TPN and number of times feedings are held due to feeding intolerance to name just a few outcomes. There is little argument that a diet for a human child composed of human milk makes a great deal of sense. Although we have come to rely on bovine sources of both milk and fortifier when human milk is unavailable I am often reminded that bovine or cow’s milk is for baby cows.
Challenges with using an exclusive human milk diet.
While it makes intuitive sense to strive for an exclusive human milk diet, there are barriers to the same. Low rates of maternal breastfeeding coupled with limited or no exposure to donor breast milk programs are a clear impediment. Even if you have those first two issues minimized through excellent rates of breast milk provision, there remains the issue of whether one has access to a human based fortifier to achieve the “exclusive” human milk diet.
The “exclusive” approach is one that in the perfect world we would all strive for but in times of fiscal constraint there is no question that any and all programs will be questioned from a cost-benefit standpoint. The issue of cost has been addressed previously by Ganapathy et al in their paper Costs of Necrotizing Enterocolitis and Cost-Effectiveness of Exclusively Human Milk-Based Products in Feeding Extremely Premature Infants. The authors were able to demonstrate that choosing an exclusive human milk diet is cost effective in addition to the benefits observed clinically from such a diet. In Canada where direct costs are more difficult to visualize and a reduction in nursing staff per shift brings about the most direct savings, such an argument becomes more difficult to achieve.
Detractors from the EHM diet argue that we have been using bovine fortification from many years and the vast majority of infants regardless of gestational age have little challenge with it. Growth rates of 15-20 g/kg/d are achievable using such fortification so why would you need to treat all patients with an EHM diet?
A Rescue Approach
In our own centre we were faced with these exact questions and developed a rescue approach. The rescue was designed to identify those infants who seemed to have a clear intolerance to bovine fortifier as all of the patients we care for under 1250g receive either mother’s own or donor milk. The approach used was as follows:
A. < 27 weeks 0 days or < 1250 g
i. 2 episode of intolerance to HMF
ii. Continue for 2 weeks
This month we published our results from using this targeted rescue approach in Winnipeg, Human Based Human Milk Fortifier as Rescue Therapy in Very Low Birth Weight Infants Demonstrating Intolerance to Bovine Based Human Milk Fortifier with Dr. Sandhu being the primary author (who wrote this as a medical student with myself and others. We are thrilled to share our experience and describe the cases we have experienced in detail in the paper. Suffice to say though that we have identified value in such an approach and have now modified our current approach based on this experience to the following protocol for using human derived human milk fortifier in our centre to the current:
A. < 27 weeks 0 days or < 1250 g
i. 1 episode of intolerance to HMF
ii. Continue for 4 weeks
B. ≥ 27 week 0 days or ≥ 750g
i. 2 episodes of intolerance to HMF
ii. Continue for 4 weeks or to 32 weeks 0 days whichever comes sooner
We believe given our current contraints, this approach will reduce the risk of NEC, feeding intolerance and ultimately length of stay while being fiscally prudent in these challenging times. Given the interest at least in Canada with what we have been doing here in Winnipeg and with the publication of our results it seemed like the right time to share this with you. Whether this approach or one that is based on providing human based human milk fortifier to all infants <1250g is a matter of choice for each institution that chooses to use a product such as Prolacta. In no way is this meant to be a promotional piece but rather to provide an option for those centres that would like to use such products to offer an EHM diet but for a variety of reasons have opted not to provide it to all.
I would consider myself fairly open minded when it comes to care in the NICU. I wouldn’t call myself a maverick or careless but I certainly am open to new techniques or technologies that may offer a better level of care for the babies in our unit. When it comes to “non-Western” concepts though such as therapeutic touch, chiropractic manipulations of infants and acupuncture (needle or otherwise) I have generally been a skeptic. I have written about such topics before with the most popular post being Laser acupuncture for neonatal abstinence syndrome. My conclusion there was that I was not a fan of the strategy but perhaps I could be more open to non traditional therapies.
This would appear to be the newest and perhaps strangest (to me at least) approach to pain relief that I have seen. I do love name of this study; the MAGNIFIC trial consisted of a pilot study on the use of auricular magnetic acupuncture to alleviate pain in the NICU from heel lances. The study was published in Acta Paediatrica this month; Magnetic Non-Invasive Acupuncture for Infant Comfort (MAGNIFIC) – A single-blinded randomized controlled pilot trial. The goal here was to measure pain scores using the PIPP scoring system for pain in the neonate before during and after a painful experience (heel lance) in the NICU. Being a pilot study it was small with only 20 needed per arm based on the power calculation to detect a 20% difference in scores. The intervention used small magnets placed at specific locations on the ear of the infant at least two hours before the heel lance was to occur. Before I get into the results, the authors of the study provide references to explain how the therapy works. Looking at the references I have to admit I was not able to obtain complete papers but the evidence is generally it would appear from adult patients. The explanation has to do with the magnetic field increasing blood flow to the area the magnet is applied to and in addition another reference suggests that there are affects the orbitofrontal and limbic regions which then impacts neurohormonal responses as seen in functional MRI. The evidence to support this is I would have thought would be pretty sparse but I was surprised to find a literature review on the subject that looked at 42 studies on the topic. The finding was that 88% of the studies reported a therapeutic effect. The conclusion though of the review was that the quality of the included studies was a bit sketchy for the most part so was not able to find that this should be a recommended therapy.
So what were the results?
Despite my clear skepticism what this study did well was that aside from the magnets, the intervention was the same. Twenty one babies received the magnetic treatments vs 19 placebo. There was a difference in the gestational ages of the babies with the magnet treated infants being about two weeks older (35 vs 33 weeks). What difference that might in and of itself have on the PIPPs scoring I am not sure. The stickers were applied to the ears with and without magnets in a randomized fashion and the nurses instructed to score them using the PIPP scoring system. Interestingly, as per their unit policy all babies received sucrose as well before the intervention of a heel lance so I suppose the information gleaned here would be the use of magnets as an adjunctive treatment. No difference was noted in the two groups before and after the heel lance but during the procedure the magnet treated infants had a difference in means (SD): 5.9 (3.7) v 8.3 (4.7), p=0.04). No differences were found in secondary measures such as HR or saturation and no adverse effects were noted. The authors conclusions were that it was feasible and appears safe and as with most pilot studies warrants further larger studies to verify the results.
Should we run out and buy it?
One of the issues I have with the study is that in the introduction they mention that this treatment might be useful where kangaroo care (KC) is not such as a critically ill infant. Having placed infants who are quite sick in KC and watched wonderful stability arise I am not sure if the unit in question under utilizes this important modality for comfort.
The second and perhaps biggest issue I have here is that although the primary outcome was reached it does seem that there was some fishing going on here. By that I mean there were three PIPP scores examined (before, during and after) and one barely reached statistical significance. My hunch is that indeed this was reached by chance rather than it being a real difference.
The last concern is that while the intervention was done in a blinded and randomized fashion, the evidence supporting the use of this in the first place is not strong. Taking this into account and adding the previous concern in as well and I have strong doubts that this is indeed “for real”. I doubt this will be the last we will hear about it and while my skepticism continues I have to admit if a larger study is produced I will be willing and interested to read it.
Look around you. Technology is increasingly becoming pervasive in our everyday lives both at home and at work. The promise of technology in the home is to make our lives easier. Automating tasks such as when the lights turn on or what music plays while you eat dinner (all scripted) are offered by several competitors. In the workplace, technology offers hopes of reducing medical error and thereby enhancing safety and accuracy of patient care. The electronic health record while being a nuisance to some does offer protection against incorrect order writing since the algorithms embedded in the software warn you any time you stray. What follows is a bit of a story if you will of an emerging technology that has caught my eye and starts like many tales as a creative idea for one purpose that may actually have benefits in other situations.
In 2012 students in Australia rose to the challenge and designed a digital stethoscope that could be paired with a smartphone. The stethoscope was able to send the audio it was receiving to the smartphone for analysis and provide an interpretation. The goal here was to help diagnose childhood pneumonia with a stethoscope that would be affordable to the masses, even “Dr. Mom” as the following video documents. Imagine before calling your health line in your city having this $20 tool in your hands that had already told you your child had breath sounds compatible with pneumonia. Might help with moving you up the triage queue in your local emergency department.
Shifting the goal to helping with newborns
Of course breath sounds are not the only audio captured in a stethoscope. Heart sounds are captured as well and the speed of the beats could offer another method of confirming the heart is actually beating. Now we have ECG, pulse oximetry, auscultation and palpation of the umbilical stump to utilize as well so why do you need another tool? It comes down to accuracy. When our own heart rates are running high, how confident are we in what we feel at the stump (is that our own pulse we are feeling?). In a review on measurement of HR by Phillipos E et al from Edmonton, Alberta, auscultation was found to take an average of 17 seconds to produce a number and in 1/3 of situations was incorrect. The error in many cases would have led to changes in management during resuscitation. Palpation of the umbilical cord is far worse. In one study “cord pulsations were impalpable at the time of assessment in 5 (19%) infants, and clinical assessment underestimated the ECG HR with a mean (SD) difference between auscultation and palpation and ECG HR of − 14 (21) and − 21 (21) beats min –1″. In another study, 55% of the time providers were incorrect when they thought the HR was under 100 BPM. This leaves the door open for something else. Might that something be the digital stethoscope?
How does the digital stethoscope fare?
Kevac AC et al decided to look at the use of the Stethocloud to measure HR after birth in infants >26 weeks gestational age at birth. The opted to use the ECG leads as the gold standard which arguably is the most accurate method we have for detecting HR. The good news was that the time to signal acquisition was pretty impressive. The median time to first heart rate with the stethoscope was 2 secs (IQR 1-7 seconds). In comparison the time for a pulse oximeter to pick up HR is variable but may be as long as one minute. In low perfusion states it may be even longer or unable to pick up a good signal. The bad news was the accuracy as shown in the Bland Altman plot. The tendency of the stethoscope was to underestimate the EKG HR by about 7 BPM. Two standard deviations though had it underestimate by almost 60 BPM or overestimate by about 50 BPM. For the purposes of resuscitation, this range is far to great. The mean is acceptable but the precision around that mean is to wide. The other issue noted was the frequent missing data from loss of contact with the patient. Could you imagine for example having a baby who has a heart rate of 50 by the stethoscope but by EKG 100? Big difference in approach, especially if you didn’t have EKG leads on to confirm. The authors note that the accuracy is not sufficient and felt that an improvement in the software algorithms might help.
Another go at it
So as suggested, the same group after having a new version with improved software decided to go at it again. This time Gaertner VD et al restricted the study to term infants. Forty four infants went through the same process again with the stethoscope output being compared to EKG lead results. This time around the results are far more impressive. There was virtually no difference between the ECG and the stethoscope with a 95% confidence interval as shown in the graphs with A being for all recordings and B being those without crying (which would interfere with the acquiring of HR). A maximal difference of +/- 18 BPM for all infants is better than what one gets with auscultation or palpation in terms of accuracy and let’s not forget the 2 second acquisition time!
Should you buy one?
I think this story is evolving and it wouldn’t surprise me if we do see something like this in our future. It certainly removes the element of human error from measuring. It is faster to get a signal than even the time it takes to get your leads on. Where I think it may have a role though is for the patient who has truly no pulse. In such a case you can have an EKG HR but the patient could be in pulseless electrical activity. Typically in this case people struggle to feel a pulse with the accuracy being poor in such situations. Using a device that relies on an actual heart contraction to make a sound provides the team with real information. Concurrent with this technology is also the rise of point of care ultrasound which could look at actual cardiac contractions but this requires training that makes it less generalizable. Putting a stethoscope on a chest is something we all learn to do regardless of our training background.
I think they could be on to something here but perhaps a little more evidence and in particular a study in the preterm infant would be helpful to demonstrate similar accuracy.