Baby Brain Cooling -- In-Depth Doctor's Interview

Ivanhoe Broadcast News Transcript with
Siva Subramanian, M.D., Neonatologist,
Georgetown University Medical Center, Washington, D.C.,
TOPIC: Baby Brain Cooling

What is this infant brain cooling device?

Dr. Subramanian: In babies who have sustained moderate to severe brain damage, in the past, I simply couldn't do anything more than support those babies. You know, I can support them with ventilators, I can support them with nutrition, I can support them with the antibiotic, I can support their blood pressure -- all of those things I can do, but there was nothing I could do to be able to diminish and decrease the change when it comes to the brain damage.

And what causes that brain damage?

Dr. Subramanian: There is a variety of things in the late pregnancy toward the delivery that can go wrong, that results in the fetus or the newborn suffering either low oxygen to the brain or low blood supply, and that's why it's called hypoxic ischemic encephalopathy, HIE. That it's a way of saying that the brain has damage.

Before this, what would happen to those children? Would they die?

Dr. Subramanian: Many, many, many of them who had severe brain damage would die. You know, we're talking about some 60 to 80 percent of those babies that had severe damage, die, and of those who survive with severe damage, most of them if not all of them have serious developmental problems. Even the babies who have moderate problems, you're talking about the 10 percent or 15 percent who die, and the 30 or 40 percent of them who survive have problems.

What's that like as a doctor, knowing how many babies have brain damage, and what was it like not being able to do anything?

Dr. Subramanian: It was really just, just frustrating. You know, there was nothing you could do other than support. Luckily some of these babies would recover, but not all of them. When this was taken through the trial and animal studies, it showed promise in multiple species. Then the study was done as a pilot in babies that showed promise, and then finally last year the study in the United States as well as the study from abroad -- these large studies showed that this particular component of cooling the brain seemed to be effective ... But it's true some of them may still have a problem.

How many babies are born with brain damage, do you have any numbers?

Dr. Subramanian: It's just about two to four babies per 1,000 babies will be born with a some kind of moderate to severe problems of damage to the brain.

So how does this cooling system work?

Dr. Subramanian: Surprisingly, it's fairly simple than any of the other interventions that have been used in the intensive care unit. For example, what we do is as soon as the baby comes, we make a determination: Is this baby eligible for going on the cooling project?

What makes the baby eligible?

Dr. Subramanian: They should have sustained moderate, severe encephalopathy, or brain damage. And that is determined by various information from the blood and also from a clinical examination -- neurological examination -- of the baby.

And they have to be full term?

Dr. Subramanian: They are either full term, or they are what we call late-full-term, which is beyond 36 weeks of gestation.

What happens is that whatever the causes -- different causes cause this problem, but whatever it is, the first insult that happens, depending on how long that would take, or how much, you know, severity it is, whether it's the damage that causes the near death advances, but then, actually, after the baby is born, he obviously will require support.

So the first damage comes in utero?

Dr. Subramanian: Most of it comes in utero at the time of delivery. Once the baby is born, we are right there, you know, helping the babies to breathe, giving oxygen, making sure the fluid is good ... the blood pressure, you know, restoring the blood pressure and oxygen that increases all of those things in the brain.

If it's got that damage in utero in the brain, then it's a likelihood of this second wave?

Dr. Subramanian: There's nothing to do to prevent a second wave, and depending upon how severe the second wave, the long-term prognosis will become obvious one way or the other.

But this cooling system will stop that?

Dr. Subramanian: We know from animal studies and in the lab studies and now baby studies that the cooling of the brain, which is what we do, seems to prevent or decrease this second wave of problems that occur in the brain, and thereby it reduces of minimizes the damage to the brain.

Does it stop it altogether?

Dr. Subramanian: Yes. Once it is blocked -- this second wave -- then it is fine, the brain is fine. But what will happen in the first wave, there is to be part of the damage to remain, but then at least it will prevent the second wave.

How exciting is this for you as a doctor?

Dr. Subramanian: This is something that, you know, for the brain, to be able to intervene, even to stop the second wave, is remarkable. From the frustrating times of just watching these babies and having the knowledge that they will continue to deteriorate, this allows for the recovery much faster and much better. Again, this is not a cure-all for everything that it has, the duration, and how extensive the damage is, and some babies, it's not going to help, but it will definitely make a difference in babies who are placed on this coolant.

How does it work?

Dr. Subramanian: If we know that the baby is eligible to be put on the blanket, we put the baby on the blanket and it circulates cool water inside.

How cold is the water inside?

Dr. Subramanian: Initially we bring it down to five degrees centigrade, so when the baby is put on, it's very cold. This blanket is connected to this small machine, which keeps it cool. There are big blankets that are available for adults, and they are put on if an adult has heatstroke.

Five degrees centigrade, what is that?

Dr. Subramanian: It's 41 degrees Fahrenheit.

How does the baby not turn blue, and...

Dr. Subramanian: Good question. See in rheumatology, we usually discourage the baby from getting cold. That's why we have all this elaborate set up, the warmers, the incubator, to keep the baby in what is called a neutral thermal environment. This one is worse. We want to make sure we teach, and specifically babies, if we bring it down to 33.5 degrees centigrade, it really seems to help, but really there are other studies that are needed to see how to you know, lower the temperature, raise the temperature, to see if it makes a difference.

What does it do for the baby? How does it actually work?

Dr. Subramanian: What it does is cool the baby's body, thereby cools the brain, because the blood is cool, and the blood circulates the brain and cools all the brain structures around.

How does that stop the brain damage?

Dr. Subramanian: The decreased temperature prevents the release of the whole bunch of substances that are causing more damage, and so we know that the lower temperature blocking those areas now prevents the second wave of damage.

How long do they have to stay on the blanket?

Dr. Subramanian: Right now, the information is that they need to be put is in the first six hours of birth. That is right now, the recommendation. Additional studies are needed to see maybe as much as eight. That is how late you can put them on that is not too late, and that is research and information that we need to know. The second part is once the baby is put on for 72 hours, and then after 72 hours, we start really warming the baby, take them off the cooling machine, an start really re-warming the baby slowly over the next six hours, and start re-warming over the next period of time.

But you leave this on during the day, the warmer, too, right?

Dr. Subramanian: Interestingly, when the baby's on the cooler, we turn them off. They're not on any heat. We remove them from the heat sources.

How do they not shiver?

Dr. Subramanian: Interestingly, babies don't have the shivering response like adults have. You know, it's not as common for us to see babies shiver as often as we see in adults.

How does it not bother them?

Dr. Subramanian: They're in a controlled environment. I think because we are constantly monitoring the babies, we can monitor their change.

Are there any side effects?

Dr. Subramanian: At this point, there are no side effects at all.

You've done it with two babies so far, what's been the result?

Dr. Subramanian: Well, I can tell you that two is not a sufficient number, but patients who were brought in from other hospitals into the NICU. It is clear that at the time they are ready to go home, they are treated like a normal baby. We need to have a follow up, but not for one or two years, but for five or 10 years, to make sure that there are no effects.

How much of a difference did it make?

Dr. Subramanian: Oh, it was remarkable, I mean, that baby would've had a serious problem of survival. If it had survived, it would've had neurological and medical problems. When they are discharged, it is done by a pediatrician, because you know, we want them examined by a pediatrician, and she was amazed.

Was there any evidence of injury?

Dr. Subramanian: No evidence at all of damage showing at the time of discharge. That's why we need long-term follow up to see if there are any problems that sustain all the way. You know we'll have to see, but there was nothing at the time of discharge.

What are cooling casts?

Dr. Subramanian: There are three different ways of doing it. One is called a full body cooling -- most of the hospitals tend to do the whole body cooling. The second type is called a cool cap, which is actually a kind of cap that is put on to circulate, and then circulates and cools the brain. This is total body cooling.

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END OF INTERVIEW

This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc., or any medical professional interviewed. Ivanhoe Broadcast News, Inc., assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors in different ways; always consult your physician on medical matters.

If you would like more information, please contact:

Georgetown MD (Patient Referral Service)
Georgetown University Children's Medical Center
3800 Reservoir Rd., N.W.
Washington, D.C. 20007
(202) 342-2400
(866) 745-2633