Can transcutaneous auricular vagus nerve stimulation do the impossible and fix the baby who won’t eat?

Can transcutaneous auricular vagus nerve stimulation do the impossible and fix the baby who won’t eat?

If you work in NICU you will have seen many babies who have passed through the stages of apnea, weaned off respiratory support and have reached a sufficient weight for discharge but alas will just not feed. Different strategies have been employed to get these infants feeding that rely in many cases on a cue based approach but in the end there are some that just won’t or can’t do it. Many of these babies will be sent home either with NG feedings or if it appears to be a more long term situation a gastrostomy tube. For this blog post I am going to present to you some novel research that suggests there may be another way to approach this and would like to thank one of the followers of my social media for alerting me to this work. You know who you are as the saying goes!

Transcutaneous Auricular Vagus Nerve Stimulation taVNS

This was an open label Phase 0 trial (few patients as a pilot) using taVNS to help improve feeding in ex-preterm or 3 recovering from HIE infants who were now past term and all headed towards a gastrostomy tube. The hospital carrying out the study entitled Transcutaneous Auricular Vagus Nerve Stimulation-Paired Rehabilitation for Oromotor Feeding Problems in Newborns: An Open-Label Pilot Study by Badran BW et al did not come out of thin air. Prior research in adult patients recovering from stroke found in multiple studies (all referenced in the paper) that motor stimulation accompanied by VNS improves motor function recovery. The objective here then was to see if stimulation of the auricular nerve along with assessment and motor treatments from an occupational therapist once a day could help improve feeding and avoid GT placement. The trial overview is as shown below.

The centre in which the study was done had a historical rate in this population of <10% of such patients avoiding a GT (all reaching term equivalent age and not showing an improvement in feeds). This was demonstrated in previous work by at the Medical University of South Carolina (MUSC). “Preterm infants who have not reached full PO feeds by 40-week gestational age (GA) and/or after 40 days of attempting PO feeds have a >90% chance of eventually needing G-tube implantation to achieve full enteral feeds (Ryan and Gehle, 2019).”

The Intervention

taVNS was done once a day during a bottle feed and timed with observed suckling and swallowing by an OT. The stimulation was stopped during a pause in feeding.

As you read this you may be concerned about side effects (as I was) of passing an electrical current to the ear and stimulating the auricular branch of the vagus nerve. This has been shown in other work to activate both afferent and efferent pathways of the vagus nerve and enhance plasticity and functional motor recovery. Could you then apply the same to improving development of the motor pathways of the preterm newborn or patient recovering from HIE? The authors examined skin irritation, pain scores and incidence of bradycardia before and during feeding while stimulation was occurring and found no difference in any of the measures. In order to minimize pain the authors increased the current by 0.1 mA until they perceived stimulation by change in facial expression, shrugging or fidgety movements. In the event of an increase in pain scoring by 3 the dose was decreased by the same amount. in the end the intervention was deemed safe without any adverse effects.

The primary outcome was ability to increase and maintain full daily PO intake for 4 days (>120 mL/kg/d and maintain a weight gain of >20 g/day until discharge.

Why you should care about the results

If you work in a hospital like mine you would probably find that once the discussion about a GT placement begins, few miraculously avoid it. In this study they found that 8 of the 14 patients or 57% avoided the GT. Their historical achievement in this regard was <10%. This could be by chance of course since the study is a small one but when looking at the PO intake between non-responders and responders they demonstrate the following.

The authors found no statistically significant increase in the non-responders after the taVNS in PO feeds but also note there were three infants born to mothers with diabetes in this group. I have commented before on the effect of diabetes on successful feeding so this certainly could have affected the success of this group. If you look at the change over time in the responder group they look graphically like there was an upwards trend in the feeding ability prior to the intervention although the increase or slope of the improvement due to small numbers was not significant. The takeoff in feeding afterwards was.

The findings in this study are extremely exciting to me. As units across the globe struggle with patient flow, one of the most common reasons for these patients to stay in hospital is no longer BPD or apnea but inability to feed. The idea that such a simple intervention that is done once daily for 30 minutes might influence the development of feeding coordination in these at risk infants is phenomenal in terms of its impact on patient flow.

If you wonder about whether this is a one off study, there is a lot of active research in this area. A quick search of clinicaltrials.gov uncovers 61 studies on taVNS recruiting at the moment for a variety of ailments. In fact the next study is a Phase 1 trial aiming to recruit 40 patients and is underway. If interested the link to the study is here.

Stay tuned!

At 22-24 weeks does practice make perfect?

At 22-24 weeks does practice make perfect?

In the book Outliers by Malcolm Gladwell he talked about 10000 hours being the threshold at which if you practiced or gained that much experience with something you could become an expert. In Sweden the approach to 22 week pregnancies and above is to resuscitate all as a strategy. I wrote about this before in At 22 weeks of gestation does your faith matter most to outcome? The information gleaned from that paper was that if you have a policy of resuscitation at these gestational ages and you compare outcomes to a centre that is selective in who they resuscitate the outcomes are better when you believe all should be resuscitated.

New Study Expands Data

The same group has published this time around the results of the same cohort from 2006-2015 but this time with developmental outcome data. The paper is entitled Outcomes of a uniformly active approach to infants born at 22-24 weeks of gestation In this paper they discuss outcomes at 234 and 24 weeks respectively in addition to the findings for 22 weeks which they covered in the paper mentioned above. The reason for sharing this study is that if I asked you to imagine going into a room right now and talking to a family at 22 – 24 weeks and predicting the outcome of their infant, my hunch is that you would not provide as rosy a picture as the group in Uppsala, Sweden.

The authors looked at a group of infants with the following breakdown by gestational age.

As you can see, there were 222 infants in total and reasonable samples at each gestational age. What differs from other larger reports such as the work by Rysavy et al in Between-Hospital Variation in Treatment and Outcomes in Extremely Preterm Infants is that in this study ALL infants were resuscitated with intention.

Not surprisingly as gestational age declines the incidence of complications rise but looking at Table 3 even at 22 weeks there was no difference in rate of NEC or need for PDA surgery. Nor was there a difference in rates of severe IVH/PVL. Rates of BPD were higher and likely attributable to the longer durations of positive pressure ventilation. Are these rates for these complications terrible though when the other option is non-intervention which for certain means death?

What about outcome?

Looking at the outcome at 2.5 years, the rate of cerebral palsy is about 1:10 to 1:20 for all GA. Hearing impairment is almost non-existent and while developmental delay is detected in 50 percent of survivors at 22 weeks only about a quarter of the infants have severe impairment.

Deciding what to do

There is no question that many of you seeing what this post was about would simply say “NO WAY” but in the end isn’t it really about a shared decision with the family? It wasn’t that long ago that we had to have a real paradigm shift in thinking about resuscitating 23 week infants. The amount of mental energy spent for teams worldwide coming to this decision was tremendous and now if you were to suggest compassionate care at 24 weeks you get a look back like you are crazy! It wasn’t that long ago that 24 weeks was considered viability in many places and now that 23 is the new 24 this is the struggle some people have now. Should we go to 22 weeks everywhere as the Swedes have? Clearly this is a decision that institutions need to look at critically and determine if they have the space to accomodate. Each infant should they survive will occupy a bed for at least 6 months. This needs to be looked at before one can just say sure this is a good idea.

In the end what the study demonstrates I believe is that the outcome at 22 and 23 weeks for that matter need not be universally dismal. There certainly is a good chance that a surviving infant will have one or more deficits but in the end I would advocate this is a conversation all units need to be having and critically look at whether each institution has the capactity to consider.

My bet is that five years from now this discussion will be moot as we will be mostly in that direction but at this time I think we are still in evolution.

Another dogma bites the dust? Two vs three hour feeding intervals for VLBW infants.

Another dogma bites the dust? Two vs three hour feeding intervals for VLBW infants.

This could turn into a book one day I suppose but I have become interested in chalenging some of my long held beliefs these days. Recently I had the honour of presenting a webinar on “Dogmas of Neonatology” for the Indian Academy of Pediatrics which examined a few practices that I have called into question (which you can watch in link). Today I turn my attention to a practice that I have been following for at least twenty years. I have to also admit it is something I have never really questioned until now! In our institution and I suspect many others, infants born under 1250g have been fed every two hours while those above every three. The rationale for this has been that a two hour volume is smaller and causes less gastric distention. This in theory would benefit these small infants by helping to not compromise ventilation or lead to reflux. Overwhelming the intestine with large distending boluses would also in theory lead to less necrotizing enterocolitis. All of this of course has been theoretical and I can thank those who preceded me in Neonatology for coming up with these rules!

Study Challenges This Old Belief

Yadav A et al published Two-hourly versus Three-hourly Feeding in Very Low Birthweight Neonates: A Randomized Controlled Trial out of India (well timed given my recent talk!). The authors randomized 175 babies born between 1000-1500g to either be fed q2h vs q3h once they began protocol feeding. The primary outcome was time to full feedings. Curiously, the paper indicates they decided to do a preplanned subgroup analysis of the 1000-1250 and 1251 -1500g groups but in the discussion it sounds like this is going to be done as a separate paper so we don’t have that data here.

The study controlled conditions for determining feeding intolerance fairly well. As per the authors:

“Full enteral feed was defined as 150 mL/Kg/day of enteral feeds, hypoglycaemia was defined as blood glucose concentration <45mg/dL [15]. Feed intolerance was defined as abdominal distension (abdominal girth ≥2 cm), with blood or bile stained aspirates or vomiting or pre-feed gastric residual volume more than 50% of feed volume; the latter checked only once feeds reached 5 mL/kg volume [16]. NEC was defined as per the modified Bells staging.”

We don’t use gastric residuals in our unit to guide cessation of feedings anymore but the groups both had residuals treated the same way so that is different but not somethign that I think would invalidate the study. The patients in the study had the baseline characteristics shown below and were comparable.

Results

It will be little surprise to you that the results indicate no difference in time to full feedings as shown in Figure 2 from the paper.

The curves for feeding advancement are essentially superimposed. Feeding every two vs three hours made no difference whatsoever. Looking at secondary outcomes there were no differences as well in rates of NEC or hypoglycemia. Importantly when examining rates of feeding intolerance 7.4% of babies in the 2 hour and 6.9% in the 3 hour groups had this issue with no difference in risk observed.

Taking the results as they are from this study there doens’t seem to be much basis for drawing the line at 1250g although it would still be nice to see the preplanned subgroup analysis to see if there were any concerns in the 1000-1250 group.

Supporting this study though is a large systematic review by Dr. A. Razak (whom I have collaborated with before). In his systematic review Two-hourly versus three-hourly feeding in very low-birth-weight infants: A systematic review and metaanalysis. he concluded there was no difference in time to full feeds but did note a positive benefit of q3h feeding in the 962 pooled infants with infants fed 3-hourly regainin birth weight earlier than infants fed 2-hourly (3 RCTs; 350 participants; mean difference [95% confidence interval] -1.12 [-2.16 to -0.08]; I= 0%; p = 0.04). This new study is a large one and will certainly strengthen the evidence from these smaller pooled studies.

Final Thoughts

The practice of switching to q2h feedings under 1250g is certainly being challenged. The question will be whether the mental barriers to changing this practice can be broken. There are many people that will read this and think “if it’s not broken don’t fix it” or resist change due to change itself. The evidence that is out there though I would submit should cause us all to think about this aspect of our practice. I will!

Single Patient Room NICUs: Time to Put Parents Minds At Ease

Single Patient Room NICUs: Time to Put Parents Minds At Ease

Some time ago Nick Hall from Graham’s Foundation posted the following question on Linkedin:

Private room vs open bay for the NICU. Can always get a quote from a parent saying it is great but….? At what cost? Impact on staff? Is parent time in those NICUs greater now? Other alternatives?

Included in the post was an article discussing the benefits of such a design.  Below I will look at the benefits and risks and conclude with an answer to his last question.

The NICUs of the 1970s through late 1990s have been described as “barn like” or “open concept” but in recent years the belief that single patient rooms (SPR) would offer greater benefit to infants led to the adoption of such a unit design across North America.  The imagined benefits would be related to improved parent comfort, creating a desire for families to spend more time with their children.  As we move to a “family centred” approach to care, a key goal of all units should be to make their families as comfortable and stress free as possible in order to have a positive experience.

Detractors meanwhile,  speak of concern regarding isolation of such infants when families do not visit and moreover a risk that such infants deprived of sensory experience will have impaired development.  Last year a paper was published that did not help quell such fears; Alterations in Brain Structure and Neurodevelopmental Outcome in Preterm Infants Hospitalized in Different Neonatal Intensive Care Unit Environments (full article in link).  This study which compared infants cared for in SPR to an open unit (the hospital in this study had a mixture of both in their NICU) found a worrisome finding at 2 year follow-up in that the infants in SPR had lower scores on language and a trend towards lower motor scores as well.  Additionally, partly explaining such findings may have been differences noted at term equivalent age in both the structure and activity of the children’s brains compared to those cared for in an open environment.  We were starting construction on a new NICU at the time this paper was published and I can tell you the findings sent shockwaves through our hospital as many wondered whether this was the right decision.

Devil Is in The Details

Looking further into this study, the urban population bore little resemblance to our own.  In our hospital all women are taught how to perform skin to skin care and the majority of our mothers spend a great deal of time with their infants.  To see how successful have a look at our recent Kangaroo Care drive results! The families in this study however the average hours per week of parent visitation over the length of stay ranged from 1.8-104 hours with a mean of 19+/- 19 hours. The average number of days held per week over the length of stay was 0-6 days with a mean of 2.4 +/-1.5 days. The average number of days held skin-to-skin over the length of stay ranged from 0-4 days, with a mean of 0.7 +/- 0.9 days.  In short they were hardly there.

Second Study Finds The Opposite

Later on in 2014 a second study on this subject was published; Single-family room care and neurobehavioral and medical outcomes in preterm infants. Infants < 1500g who were admitted to an NICU between 2008 and 2012 were compared with respect to medical and neurobehavioral outcomes at discharge. Participants included 151 infants in an open-bay NICU and 252 infants after transition to a SPR NICU.

Statistically significant results (all Ps ≤.05) showed that infants in the SPR NICU weighed more at discharge, had a greater rate of weight gain, required fewer medical procedures, had a lower gestational age at full enteral feed and less sepsis, showed better attention, less physiologic stress, less hypertonicity, less lethargy, and less pain. Nurses reported a more positive work environment and attitudes in the SPR NICU.

This study in fact demonstrated greater maternal involvement in a SPR with improvement in outcomes across the board.  It would seem then that in a SPR environment, provided there is enough family visitation and involvement this model truly is superior to the open concept.  Furthermore despite concerns by some nurses that the loss of line of sight to their patients will make for a more stressful working environment this does not seem to be the case.

What About Families Who Cannot or Simply Aren’t Visiting Frequently?

The reality is that there are many reasons for parents to be absent for long periods during their newborns stay. Having a home outside of the city with other children to care for, work obligations, or loss of custody and abandonment due to apprehension are just some of these reasons.  In our hospital, at least 15-20% of all patients admitted are from outside Winnipeg.  The evidence as I see it supports the move to a SPR but what do we do for those children who need more visitation?  The solution is a cuddler program.
CuddlerIn our new hospital we are grateful for the generosity of our Children’s Hospital Foundation who secured a donor to pay for a coordinator of such a program.  The veteran parent who is leading this program ensures that no infant goes beyond a set period of time without feeling the touch or hearing the sound of a voice.  Such a program is in fact already in place at our other tertiary hospital and was featured in a lovely article attached here.  Taking all the information together that is out there I think that if we can provide the necessary stimulation from both touch and auditory stimuli as well we can provide these infants with the developmental needs that each of them requires.

The SPR is the right design in my mind for families with many benefits that spring forth in such an environment. This need not be a win-lose scenario for your hospital. Do not underestimate the power of a cuddler and don’t hesitate to seek support to initiate such a program.  It could mean the difference from going from good to great!

Surfactant and inhaled nitric oxide make beautiful music together

Surfactant and inhaled nitric oxide make beautiful music together

If you work in Neonatology you no doubt have listened to people talk in rounds or at other educational sessions about the importance of opening the lung. Many units in the past were what you might call “peepaphobic” but over time and with improvements in technology many centers are adopting an attitude that you use enough PEEP to open the lung. There are some caveats to this of course such as there being upper limits to what units are comfortable and not just relying on PEEP but adding in surfactant when necessary to improve pulmonary compliance.

When we think about giving nitric oxide the importance of opening the lung can’t be stressed enough. I have heard it said many times when a baby has been found to be a “non responder” to inhaled nitric oxide that they may have been so because the lung wasn’t open. What we mean by this is that the distal alveoli are open. One can administer all the iNO in the world but if the majority of alveoli are collapsed the drug can’t get to the pulmonary vasculature and cause the pulmonary vasodilation that is so sorely needed in the presence of hypoxemic respiratory failure. Surfactant and inhaled nitric oxide in the presence of hypoxemic respiratory failure could be a great combo as one would help open the alveoli and then the iNO could address any pulmonary vasoconstriction which might be exacerbating the hypoxemic state.

Study Tests This Theory

Researchers in Chile led by Gonzalez A published Early use of combined exogenous surfactant and inhaled nitric oxide reduces treatment failure in persistent pulmonary hypertension of the newborn: a randomized controlled trial in the Journal of Perinatology. The concept of this study was to compare in a double blind RCT for 100 patients (based on a power calculation looking for a 25% reduction in treatment failure) whether provision of surfactant as up to 2 doses and iNO would be better than just iNO alone. Included infants needed an oxygenation index (OI = MAPXFiO2/pO2) of 20 or more to qualify and treatment failure was an OI of 40 or more. The patients recruited were similar in common characteristics including types of conditions that would benefit from iNO. RDS, meconium aspiration syndrome and pneumonia certainly have been shown to benefit from surfactant before while in the PPHN category that is questionable. In order to ensure that it was not just the primary disease but pulmonary hypertension that was present as well, all patients required confirmation of pulmonary hypertension prior to enrollment via ECHO with either a TR jet indicating a pulmonary pressure at least 2/3 of systemic or right to left shunting at the ductal or atrial level.

The results of the study demonstrated a clear difference in the primary outcome.

Patients receiving the combination of surfactant prior to starting iNO showed a faster reduction in OI than those receiving iNO alone. In fact the reduction in primary outcome of treatment failure was over 50% different while the power calculation had been based on only a 25% difference. That’s ok as this means there were more than enough patients to demonstrate a difference. As a secondary outcome the rate of ECMO or death was also different between the groups favouring use of surfactant.

It works so now what?

Who doesn’t like seeing a study that confirms what you have long believed. I feel that this study validates the teaching I received throughout the years about ensuring the lung is open before giving iNO. There are some caveats to this however. About 90% of the patients studied had conditions present (RDS, MAS, pneumonia) for which surfactant would have been indicated anyway. If this study had been done let’s say in patients with asphyxia induced pulmonary hypertension and clear lungs the surfactant may have made no difference as the lungs were already open. I mention this as I don’t think readers of this analysis need to jump to the conclusion that every time there is a patient with PPHN that you MUST give surfactant. What I think this illustrates though is the importance of first asking the question if iNO is being considered “Have I opened the lungs?”. The next time you encounter such a patient consider whether you are using enough PEEP and whether surfactant is indicated. The bottom line is if the lung isn’t open then all the iNO in the world isn’t going to make much difference!