Monday, August 18, 2008

Part II of children are not just tiny adults: Newborn pain

I heard a great talk last week on neonatal pain. It was honestly not even a topic that I had considered before. Of course all humans have pain--it never even occurred to me that they might not. Apparently, it wasn't until about twenty years ago that the idea that a premature infant could even feel pain was medically accepted. The thought was that they were born before their pain circuits fully matured, and therefore were incapable of feeling pain. Newer studies in fact shown that premature infants are HYPER-sensitive to pain.

One great tip I learned while on my pediatric rotation is that the most important developmental milestone could be considered the social smile at 2 months old. Up until 2 months, it is very difficult to tell if a baby is in pain or sick. If a child has lost their social smile, there is an excellent chance they need more advanced medical care. So how do we tell if a newborn, or even more dramatically, a premature infant is in pain?

It is not as easy as you might think. Testing (and common sense) has shown that crying is completely non-specific. Babies cry if they are upset, hungry, tired, etc. Grimacing and withdrawal reflexes have also proven to be a poor indicators. Additionally, in the neonatal intensive care unit (NICU), for medical reasons, babies are often sedated or groggy from medications. This further blurs our ability to read any cues they might give us. There are >40 scales out there, but none of them are thought to be the ideal way to assess neonatal pain.

From the Archives of Pediatric and Adolescent Medicine is the study "Do we still hurt newborn babies?". In the NICU, in their study, each baby had on average 14 painful events each day. This ranged from pulling off tape, to heel sticks, to suctioning. Many times we don't even think to give any comfort during these procedures. Therapeutic options don't even have to be limited to just medication. You can dim the lights and noise to create less stressful environment and every medical student at some point has been on sweeties duty. This is where you dip the pacifier [or your finger] into a sucrose solution to let the baby calm itself on something sweet. This honestly works like magic. In this study, they found that less than 35% of newborns received any preceding intervention. Some studies suggest that neonates may be unable to experience the analgesic (pain relieving) effects of adult medications, such as morphine. They might just experience the sedative effects.

In my own work environment, cribs and incubators often have mirrors (so that the infants can look at themselves and receive visual stimulation), music, and mobiles. Hopefully other hospitals are also beginning to recognize the importance of treating neonatal pain; I just wish there were more quality studies out there to better guide us. Clearly, treating neonates like little adults just doesn't cut it.

Not only do neonates experience pain, they also remember it. The pain we experience as infants changes the way we will always react to pain. In mouse models, neonatal surgery affects the way adult mice react to pain stimuli. Similar results have been shown in humans. I have heard stories of former premature babies brought into the pediatrician's office who shriek if you touch their feet. Maybe they remember the heel sticks?


Habladora said...

Wow - this is a great, and terrifying, post. Not to show my ignorance, but what are heel sticks?

Another Anonymous Poster said...

In a preemie, the blood vessels are too small to put in a needle or an IV easily (and they tend to collapse quickly when you do). Instead, they use a capillary tube and 'stick' it into the preemie's heel to draw a few drops of blood, enough to do whatever test needs to be done. Hence, "heel sticks".

Summer said...

I've done activist work against circumcision and I can say there are some nurses and doctors who still believe that infants do not feel pain. I've heard that they are incapable of feeling pain for the first few hours and days. One nurse angrily told me that infants feel no pain for the first 10 days of their life. If this is the thought of full term infants, I can imagine that many feel premature babies are certainly unable to feel pain.

It's sad to think how they may be poked, prodded, and tested without any thought to that they may actually feel something.

daedalus2u said...

I think the analgesic effect of sucking on something sweet may be due to a greater placebo effect in infants mentioned earlier. The only sweet thing and infant could be sucking on in "the wild", is mom, and if your mom is holding you and she feels safe enough to nurse, then as far as an infant is concerned, all is right with the world.

On the premie experiment, some moms of premies have mentioned that their older premies are conditioned to sounds like tape being unwrapped and plastic packages being opened because these sounds preceded painful procedures in the NICU.

Mächtige Maus said...

This is a fascinating post. Perhaps at some time Agincourt and I can ask our niece if she has hypersensitive issues to pain since she was a preemie. To date, what we have noticed is that she actually has a higher tolerance to discomfort than most children her age. We often wonder if that is indeed a direct result of her being a preemie and therefore experiencing an early exposure to pain.

Anonymous said...

I did see some studies that show former preemies can have higher pain thresholds, but some suggest that they are ultimately more sensitive. It just underlies that we don't really know what is going on with newborn pain. Before discharge from a hospital, the average premature neonate has >500 painful events while in the NICU.

Renee said...

It would seem to me to be common sense that a baby can feel pain and can be comforted by touch, soothing sounds and smells. I especially believe in touch as a potential healer. When you think about an average day how often do we touch each other?...I don't believe that this is accidental. The more we are touched the more we desire it, and the more it comforts us.
As soon as I my 2 year old realizes that my eyes are open, the first thing he does is come over and kiss me. This is something initiated by him. He makes it his duty to make sure that my day begins with a kiss, morning breathe and all. He gives me the biggest kiss and smiles his largest smile of the day. Not only does this interaction make me happy, it gives him joy. I know that there is a tendency to medicalize human interactions but I think that it is very important that we realize the degree to which we are social beings and dependent on each other.