Using the printed word to treat apnea of prematurity

Using the printed word to treat apnea of prematurity

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.

Lastly, with the move to single patient rooms there is one study that demonstrated the isolation encountered from infrequent contact with their newborn can have a long lasting effect on development.  The article by Pineda RG et al Alterations in brain structure and neurodevelopmental outcome in preterm infants hospitalized in different neonatal intensive care unit environments. had a mean parental visitation of 19 +/- 19 hours a week or a little over 2 hours a day but with a very large standard deviation meaning many infants had almost no visitation.  The message here is that while quiet is good for infant development, too much can be a bad thing.  Maybe live reading or even recordings are a way around that.

How long should we treat preterm infants with caffeine?

How long should we treat preterm infants with caffeine?

Much has been written about methylxanthines over the years with the main questions initially being, “should we use them?”, “how big a dose should we use” and of course “theophylline vs caffeine”. At least in our units and in most others I know of caffeine seems to reign supreme and while there remains some discussion about whether dosing for maintenance of 2.5 -5 mg/kg/d of caffeine base or 5 – 10 mg/kg/d is the right way to go I think most favour the lower dose. We also know from the CAP study that not only does caffeine work to treat apnea of prematurity but it also appears to reduce the risk of BPD, PDA and duration of oxygen therapy to name a few benefits. Although initially promising as providing a benefit by improving neurodevelopmental outcomes in those who received it, by 5 and 11 years these benefits seem to disappear with only mild motor differences being seen.

Turning to a new question

The new query though is how long to treat? Many units will typically stop caffeine somewhere between 33-35 weeks PMA on the grounds that most babies by then should have outgrown their irregular respiration patterns and have enough pulmonary reserve to withstand a little periodic breathing. Certainly there are those who prove that they truly still need their caffeine and on occasion I have sent some babies home with caffeine when they are fully fed and otherwise able to go home but just can’t seem to stabilize their breathing enough to be off a monitor without caffeine. Then there is also more recent data suggesting that due to intermittent hypoxic episodes in the smallest of infants at term equivalent age, a longer duration of therapy might be advisable for these ELBWs. What really hasn’t been looked at well though is what duration of caffeine might be associated with the best neurodevelopmental outcomes. While I would love to see a prospective study to tackle this question for now we will have to do with one that while retrospective does an admirable job of searching for an answer.

The Calgary Neonatal Group May Have The Answer

Lodha A et al recently published the paper Does duration of caffeine therapy in preterm infants born ≤1250 g at birth influence neurodevelopmental (ND) outcomes at 3 years of
age? This retrospective study looked at infants under 1250g at birth who were treated within one week of age with caffeine and divided them into three categories based on duration of caffeine therapy. The groups were as follows, early cessation of caffeine ≤ 14 days (ECC), intermediate cessation of caffeine 15–30 days (ICC), and late cessation of
caffeine >30 days (LCC).  In total there were 508 eligible infants with 448 (88%)  seen at 3 years CA at follow-up. ECC (n = 139), ICC (n = 122) and LCC (n = 187).  The primary outcome here was ND at 3 years of age while a host of secondary outcomes were also examined such as RDS, PDA, BPD, ROP as typical morbidities.  It made sense to look at these since provision of caffeine had previously been shown to modify such outcomes.

Did they find a benefit?

Sadly there did not appear to be any benefit regardless of which group infants fell in with respect to duration of caffeine when it came to ND. When looking at secondary outcomes there were a few key differences found which favoured the ICC group.  These infants had the lowest days of supplemental oxygen, hospital stay ROP and total days of ventilation.  This middle group also had a median GA 1 week older at 27 weeks than the other two groups.  The authors however did a logistic regression and ruled out the improvement based on the advanced GA.  The group with the lowest use of caffeine had higher number of days on supplemental oxygen and higher days of ventilation on average than the middle but not the high caffeine group.  It is tempting to blame the result for the longer caffeine group on these being babies that were just sicker and therefore needed caffeine longer.  On the other hand the babies that were treated with caffeine for less than two weeks appear to have likely needed it longer as they needed longer durations of oxygen and were ventilated longer so perhaps were under treated. What is fair to say though is that the short and long groups having longer median days of ventilation were more likey to have morbidities associated with that being worse ROP and need for O2.  In short they likely had more lung damage.  What is really puzzling to me is that with a median GA of 27-28 weeks some of these kids were off caffeine before 30 weeks PMA and in the middle group for the most part before 32 weeks!  If they were in need of O2 and ventilation for at least two weeks maybe they needed more caffeine or perhaps the babies in these groups were just less sick?

What is missing?

There is another potential answer to why the middle group did the best.  In the methods section the authors acknowledge that for each infant caffeine was loaded at 10 mg/kg/d.  What we don’t know though is what the cumulative dose was for the different groups.  The range of dosing was from 2.5-5 mg/kg/d for maintenance.  Lets say there was an over representation of babies on 2.5 mg/kg/d in the short and long duration groups compared to the middle group.  Could this actually be the reason behind the difference in outcomes?  If for example the dosing on average was lower in these two groups might it be that with less respiratory drive the babies in those groups needed faster ventilator rates with longer durations of support leading to more lung damage and with it the rest of the morbidities that followed?

It would be interesting to see such data to determine if the two groups were indeed dosed on average lower by looking at median doses and total cumulative doses including miniloads along the way.  We know that duration may need to be prolonged in some patients but we also know that dose matters and without knowing this piece of information it is tough to come to a conclusion about how long exactly to treat.

What this study does though is beg for a prospective study to determine when one should stop caffeine as that answer eludes us!