Look around an NICU and you will see many infants living in incubators. All will eventually graduate to a bassinet or crib but the question always is when should that happen? The decision is usually left to nursing but I find myself often asking if a baby can be taken out. My motivation is fairly simple. Parents can more easily see and interact with their baby when they are out of the incubator. Removing the sense of “don’t touch” that exists for babies in the incubators might have the psychological benefit of encouraging more breastfeeding and kangaroo care. Both good things.
Making the leap
For ELBW and VLBW infants humidity is required then of course they need this climate controlled environment. Typically once this is no longer needed units will generally try infants out of the incubator when the temperature in the “house” is reduced to 28 degrees. Still though, it is not uncommon to hear that an infant is “too small”. Where is the threshold though that defines being too small? Past research studies have looked at two points of 1600 vs 1800g for the smallest of infants. One of these studies was a Cochrane review by New K, Flenady V, Davies MW. Transfer of preterm infants for incubator to open cot at lower versus higher body weight. Cochrane Database Syst Rev 2011;(9). This concluded that early transition was safe for former ELBWs at the 1600g weight cut off.
What about the majority of our babies?
While the ELBW group takes up a considerable amount of energy and resources the later preterm infants from 29 to 33 6/7 weeks are a much larger group of babies. How safe is this transition for this group at these weights? Shankaran et al from the NICHD published an RCT on this topic recently; Weaning of Moderately Preterm Infants from the Incubator to the Crib: A Randomized Clinical Trial. The study enrolled
Infants in this gestational age range with a birth weight <1600g were randomly assigned to a weaning weight of 1600 or 1800 g. Within 60 to 100 g of weaning weight, the incubator temperature was decreased by 1.0°C to 1.5°C every 24 hours until 28.0°C. Weaning to the crib occurred when axillary temperatures were maintained 36.5°C to 37.4°C for 8 to 12 hours. Clothing and bedcoverings were standardized. The primary outcome was LOS from birth to discharge.
What did they find?
A total of 366 babies were enrolled (187 at 1600g and 179 at 1800g. Baseline characteristics of the two groups revealed no statistical differences. Mean LOPS was a median of 43 days in the lower and 41 days in the higher weight group (P = .12). After transition to a crib weight gain was better in the lower weight group, 13.7 g/kg/day vs 12.8 g/kg/ day (P = .005). Tracking of adverse events such as the incidence of severe hypothermia did not differ between groups. The only real significant difference was a better likelihood of weaning from the incubator in the higher group at 98% success vs 92% on the first attempt. Putting. That in perspective though, a 92% success rate by my standards is high enough to make an attempt worthwhile!
The authors have essentially shown that whether you wean at the higher or lower weight threshold your chances of success are pretty much the same. Curiously, weight gain after weaning was improved which seems counter intuitive. I would have thought that these infants would have to work extra hard metabolically to maintain their temperature and have a lower weight gain but that was not the case. Interestingly, this finding has been shown in another study as well; New K, Flint A, Bogossian F, East C, Davies MW. Transferring preterm infants from incubators to open cots at 1600 g: a multicentre randomised controlled trial. Arch Dis Child Fetal Neonatal Ed 2012;97:F88-92. Metabolic rate has been shown to increase in these infants but skin fold thickness has been shown to increase as well in infants moved to a crib. How these two things go together is a little beyond me as I would have thought that as metabolic rate increases storage of tissue would slow. Not apparently the case but perhaps just another example of the bodies ability to overcome challenges when put in difficult situations. A case maybe of “what doesn’t kill you makes you stronger?”
The authors do point out that the intervention was unmasked but the standardization of weaning procedure and garments used in the cribs should have overcome that. There were 36% of parents who did not consent to the study so their inclusion could have swayed the results perhaps but the sample size here was large despite that. That the final results agree with findings in ELBW infants suggests that the results are plausible.
What I think this study does though is tell us overall that weaning at a smaller weight is at least alright to try once one is at minimal settings in an incubator. Will this change your units practice? It is something that at least merits discussion.
“Safety should be a birthright” Clementine Wamariya
Before continuing with the posts I thought I should address a very important issue when it comes to KC
As I have said before I believe fully in the benefits of KC for any infant (premature or full term). To enable that infant and family to benefit from KC, safety must always be part of the equation.
A risk factor for Apparent Life threatening Events (ALTE) is KC that is unsupervised and without an attentive observer. Despite this risk, when comparisons are made between ALTEs with KC and ALTEs without; ALTEs without KC were higher. Another term that has been talked about since KC has been increasing in NICUs and Maternal Child areas is Sudden Unexpected Postnatal Collapse (SUPC), a rare event but can have catastrophic consequences.
Risk factors for SUPC include:
First breastfeeding attempt
Mother in episiotomy position
A primiparous mother
Parents left alone with baby during the first hours after birth
Implementations to Reduce SUPC:
A continual secure surveillance of the newborn in the first hours and days of life
Safe early skin to skin care (SSC) in the delivery room
Safe breastfeeding establishment in the first days of life
Secure positioning of the infant during sleep
SUPC of Newborn infants: A review of cases, definitions, risks and preventative measures. Herlenius E., and Kuhn P. (2013)
Our Maternal/Child department is incredibly busy as are most centres these days. Every effort must always be made to fully educate staff and the families about safety for our newborns.
Safety Education should include:
Anytime KC is happening there should be attentive and continuous observation
To facilitate respiratory expansion, infant should be elevated off of horizontal (Bohnhourst, 2010; Heinman et al, 2010)
There should be no obstruction of the infant’s nose and the head needs to be turned to one side
Neck should not be flexed or extended but in a slight “sniffing” position
Infant’s body should be positioned to maintain ventral surface to ventral surface contact
Infant should be secured with blankets, wraps and/or parent’s hands to prevent sliding (I prefer using the parent’s hands to contain the infant and then cover them both with blankets. I feel the parent has better awareness of babe’s position that way)
Our unit is made up of pods with curtains that can divide each bedside. When our parents are holding KC those curtains are to be left open so the nurse can observe. We prop our parent’s arms so they don’t get tired and tuck both in with blankets. We have also created a standard work procedure for our intubated and fragile infants so staff transfer and secure the infant the same way each time.
We also attend all high-risk deliveries. When I leave babies in kangaroo position after a delivery, I always make sure the baby’s face is turned toward the L&D nurse, not away so she can easily observe the infant even if she is tending to mom.
Everything we do in life has risks; swimming, driving a vehicle, voting, etc. To do these things there are safety measures put in place. You wouldn’t avoid driving a car because it has safety risks. You take driving lessons, pass a test, follow the rules of the road, and that way you get to enjoy the benefits of driving. I feel it is the same with KC, education and safety measures should always be in place so that infant and family can enjoy the benefits.
As a Neonatologist, there is no question that I am supportive of breast milk for preterm infants. When I first meet a family I ask the question “are you planning on breastfeeding” and know that other members of our team do the same. Before I get into the rest of this post, I realize that while breast milk may be optimal for these infants there are mother’s who can’t or won’t for a variety of reasons produce enough breast milk for their infants. Fortunately in Manitoba and many other places in the world breast milk banks have been developed to provide donor milk for supporting these families. Avoidance of formula in the early days to weeks of a ELBWs life carries benefits such as a reduction in NEC which is something we all want to see.
Mother’s own milk though is known to have additional benefits compared to donor milk which requires processing and in so doing removes some important qualities. Mother’s own milk contains more immunologic properties than donor including increased amounts of lactoferrin and contains bioactive cells. Growth on donor human milk is also reduced compared to mothers’ own milk and lastly since donor milk is obtained from mothers producing term milk there will be properties that differ from that of mothers producing fresh breast milk in the preterm period. I have no doubt there are many more detailed differences but for basic differences are these and form the basis for what is to come.
The Dose Response Effect of Mother’s Own Milk
Breast milk is a powerful thing. Previous studies on the impact of mother’s own milk (MOM) have shown that with every increment of 10 mL/kg/d of average intake, the risk of such outcomes as BPD and adverse developmental outcomes are decreased. In the case of BPD the effect is considerable with a 9.5% reduction in the odds of BPD for every 10% increase in MOM dose. With respect to developmental outcome ach 10 mL/kg/day increase in MOM was associated with a 0.35 increase in cognitive index score.
The same group just published another paper on this cohort looking at a different angle. NICU human milk dose and health care use after NICU discharge in very low birth weight infants. This study is as described and again looked at the impact of every 10 mL/kg increase in MOM at two time points; the first 14 and the first 28 days of life. Although the data for the LOVE MOM trial was collected prospectively it is important to recognize how the data for this study was procured. At the first visit after NICU discharge the caregiver was asked about hospitalizations, ED visits and specialized therapies and specialist appointments. These were all tracked at 4 and 8 months of corrected age were added to yield health care utilization in the first year, and the number of visits or provider types at 4, 8, and 20 months of corrected age provided health care utilization through 2 years.
What were the results?
“Each 10 mL/kg/day increase in HM in the first 14 days of life was associated with 0.26 fewer hospitalizations (p =
0.04) at 1 year and 0.21 fewer pediatric subspecialist types (p = 0.04) and 0.20 fewer specialized therapy types (p = 0.04) at 2 years.” The results at 28 days were not statistically significant. The authors reported both unadjusted and adjusted results controlling for many factors such as gestational age, completion of appointments and maternal education to name a few which may have influenced the results. The message therefore is that the more of MOM a VLBW is provided in the first 14 days of life, the better off they are in the first two years of life with respect to health care utilization.
That even makes some sense to me. The highest acuity typically for such infants is the first couple of weeks when they are dealing with RDS, PDA, higher oxygen requirements etc. Could the protective effects of MOM have the greatest bang for your buck during this time. By the time you reach 28 days is the effect less pronounced as you have selected out a different group of infants at that time point?
What is the weakness here though? The biggest risk I see in a study like this is recall bias. Many VLBW infants who leave the NICU have multiple issues requiring many different care providers and services. Some families might keep rigorous records of all appointments in a book while others might document some and not others. The big risk here in this study is that it is possible that some parents overstated the utilization rates and others under-reported. Not intentionally but if you have had 20 appointments in the first eight months could the number really by 18 or 22?
Another possibility is that infants receiving higher doses of MOM were healthier at the outset. Maternal stress may decrease milk production so might mothers who had healthier infants have been able to produce more milk? Are healthier infants in the first 14 days of life less likely to require more health care needs in the long term?
How do we use this information?
In spite of the caveats that I mentioned above there are multiple papers now showing the same thing. With each increment of 10 mL/kg of MOM benefits will be seen. It is not a binary effect meaning breastfed vs not. Rather much like the medications we use to treat a myriad of conditions there appears to be a dose response. It is not enough to ask the question “Are you intending to breastfeed?”. Rather it is incumbent on all of us to ask the follow-up question when a mother says yes; “How can we help you increase your production?” if that is what the family wants>
Much has been written on the topic of cord clamping. There is delayed cord clamping of course but institutions differ on the recommended duration. Thirty seconds, one minute or two or even sometimes three have been advocated for but in the end do we really know what is right? Then there is also the possibility of cord milking which has gained variable traction over the years. A recent review was published here.
Take the Guessing Out of the Picture?
Up until the time of birth there is very little pulmonary blood flow. Typically, about 10% of the cardiac output passes through the lungs and the remained either moves up the ascending aorta or bypasses the lungs via the ductus arteriosus. After birth as the lung expands, pulmonary vascular resistance rapidly decreases allowing cardiac output to take on the familiar pattern which we all live with. Blood returning from the systemic venous circulation no longer bypasses the lung but instead flows through pulmonary capillaries picking up oxygen along the way. One can imagine then that if a baby is born and the cord is clamped right away, blood returning from the systemic circulation continues to bypass the lung which could lead to hypoxemia and reflexive bradycardia. This has been described previously by Blank et al in their paper Haemodynamic effects of umbilical cord milking in premature sheep during the neonatal transition.
A group of researchers from the Netherlands published a very interesting paper Physiological-based cord clamping in preterm infants using a new purpose-built resuscitation table: a feasibility study this month. The study centres around a resuscitation table called the Concord that is brought to the mother for resuscitation after birth. The intervention here was applied to infants 26 to 35 weeks gestational age. The cord was clamped after each of the following was achieved for an infant indicating successful transition with opening of the lung and establishment of an FRC.
1. Establishment of adequate breathing (average tidal volume ≥4 mL/kg) on CPAP. They used a mask capable of measuring expired tidal volumes.
2. HR above 100 bpm
3. SpO2 above 25th percentile using FiO2 <0.4
In this way, the cord was only clamped once the baby appeared to have physiologically made the transition from dependence on umbilical cord blood flow to ventilation perfusion matching in the lung. Although 82 mothers consented only 37 preterm infants were included in the end. Exclusion criteria were signs of placental abruption or placenta praevia, signs of severe fetal distress determined by the clinician and the necessity for an emergency caesarean section ordered to be executed within 15 min. This really was a proof of concept study but the results are definitely worth looking at.
How Did These Babies Do?
There are many interesting findings from this study. The mean time of cord clamping was 4 minutes and 23 seconds (IQR 3:00 – 5:11). Heart rate was 113 (81–143) and 144 (129–155) bpm at 1 min and 5 min
after birth. Only one patient developed bradycardia to <60 BPM but this was during a mask readjustement. The main issue noted as far as adverse events was hypothermia with a mean temperature of 36.0 degrees at NICU admission. Almost 50% of infants had a temperature below 36 degrees. Although the authors clearly indicate that they took measures to prevent heat loss it would appear that this could be improved upon!
What stands out most to me is the lengthy duration of cord clamping. This study which used a physiologic basis to determine when to clamp a cord has demonstrated that even at 1 minute of waiting that is likely only 1/4 of the time needed to wait for lung expansion to occur to any significant degree. I can’t help but wonder how many of the patients we see between 26-35 weeks who have a low heart rate after delivery might have a higher heart rate if they were given far more time than we currently provide for cord clamping.
I can also see why cord milking may be less effective. Yes, you will increase circulating blood volume which may help with hemodynamic stability but perhaps the key here is lung expansion. You can transfuse all the blood you want but if it has nowhere to go just how effective is it?
As we do more work in this area I have to believe that as a Neonatal community we need to prepare ourselves for the coming of the longer delay for cord clamping. Do we need to really have the “Concord” in every delivery or perhaps it is time to truly look at durations of 3-4 minutes before the team clamps the cord.
As the saying goes, sometimes less is more. In recent years there has been a move towards this in NICUs as the benefits of family centred care have been shown time and time again. Hi tech and new pharmaceutical products continue to develop but getting back to the basics of skin to skin care for many hours and presence of families as an integral team member have become promoted for their benefits. The fetus is a captive audience and hears the mother’s heart beat and voice after the development of hearing sometime between 24-26 weeks gestational age. This is a normal part of development so it would stand to reason that there could be a benefit to hearing this voice especially after hearing has developed and the fetus has grown accustomed to it. Hospital including my own have developed reading programs for our patients and some companies have developed speakers in isolettes designed to limit the maximum decibel to 45 but allowing parents to make recordings of their voices. Music may be played through these speakers as well but today we will focus on the benefit of voice.
Could reading to your baby reduce apnea of prematurity?
This is the question that Scala M et al sought to answer in their paper Effect of reading to preterm infants on measures of cardiorespiratory stability in the neonatal intensive care unit. This was a small prospective study of the impact of parental reading on cardiorespiratory stability in preterm NICU infants. Eighteen patients were enrolled who were born between 23-31 weeks gestation. The study was carried out when the babies were between 8-56 days old at a mean postnatal age of 30 weeks. Each patient served as their own control by comparing episodes of oxygen desaturation to <85% during pre-reading periods (3 hours and 1 hour before) to during reading and then 1 hour post reading. Parents were asked to read or create a recording lasting a minimum of 15 min but up to 60 min of recorded reading. The parents were offered a standard set of books that had a certain rhythm to the text or could choose their own. Recorded reading was played for infants up to twice per day by the bedside nurse. While it was small in number of patients the authors point out that the total exposure was large with 1934 min of parental bedside reading analyzed (range 30–270 min per infant, mean 123, median 94 min). Patients could be on respiratory support ranging from ventilators to nasal cannulae.
Was it effective?
It certainly was. I should mention though that the authors excluded one patient in the end when it was found that they failed their hearing screen. Arguably, since the infant could not have benefited from the intervention effect this makes sense to me. As shown from table 3 there was a statistical reduction in desaturation events during the reading period which was sustained in terms of a downward trend for one hour after the intervention was completed. In case you are asking was the difference related to oxygen use the answer is no. There was no difference in the amount of oxygen provided to patients. While the events were not eliminated they were certainly reduced. The other point worth mentioning is that there appears to be a difference between live (through open portholes) vs prerecorded reading (through a speaker in the isolette).
Now for a little controversy
Does source of the reading matter? The authors found that maternal had a greater effect than paternal voice. As a father who has read countless books to his children I found this a little off-putting. As a more objective critic though I suppose I can buy the biologic plausibility here. I suspect there is an independent effect of voice having a positive impact on development. If we buy the argument though that the voice that the fetus has most been accustomed to is the mothers, then the findings of an augmented effect of the maternal voice over fathers makes some sense. I will have to put my ego aside for a moment and acknowledge that the effect here could be real.
There will no doubt need to be larger studies done to drill down a number of questions such as what is the ideal type of reading, duration, rhythmic or non etc but this is a great start. I also think this falls into the category of “could this really be a bad thing?”. Even if in the end no benefit is shown to this type of intervention, the potential for family bonding with their preterm infant alone I think is cause for embracing this intervention.