Barbara
Nesbitt: "Hi,
I'm Barbara Nesbitt and I'm here at AIUM with Dr. Barry Schifrin, who's a
member of the Fetal Monitoring Editorial Advisory Board at OBGYN.net.
We're going to discuss the pitfalls of fetal monitoring. Welcome! I know
you have been involved in this since the earliest days of fetal
monitoring."
Dr.
Barry Schifrin:
"'Committed' is a better word..."
Barbara
Nesbitt:
"'Committed' is better, yes, and I know that you are very interested
in the wonderful things that they thought it was going to do. Does it
actually do all of that? Of course, it does do wonderful things, but where
did they lose some of what they thought it was going to do, and what was
that?"
Dr.
Barry Schifrin:
"I'm not sure they lost some of the things that they thought it was
going to do. Clearly, it was introduced in the later part of 1969 and the
early 1970s with extraordinary expectations. The expectations were that it
would lower the fetal-neonatal mortality, morbidity, and the risk of
neurologic injury. They thought that, paradoxically, it would now lower
the caesarian section rate because most caesarian sections for fetal
distress at the time were based on the stethoscope, and they didn't really
correlate with outcomes. So we have not lived up to all of those
expectations for a number of reasons, part of which were the expectations
themselves."
Barbara
Nesbitt: "Tell
us a little bit about some of the wonderful things that it does and why it
is good to have it."
Dr.
Barry Schifrin:
"There are several obvious benefits. One is, statistically, it has
simply helped lower the death rate during labor so that stillbirth today
is virtually unheard of and there are, to my knowledge, no reported cases
of an unexpected stillbirth. So before the advent of fetal monitoring, for
example, you would be at the bedside, hear a heart rate, and it was not
uncommon to go back some time later and all of a sudden the heart rate had
disappeared. That has essentially been eliminated. The effect on the
caesarian section rate is hotly debated. It's obvious that the more you
know about interpreting fetal monitoring, the fewer unnecessary caesarian
sections will occur as a result of changes in the heart rate pattern. The
final thing has to do with helping babies prevent injury, and that has
raised two problems. One, you have to know how injury occurs, and that was
a problem because in the early days of fetal monitoring the whole idea was
that if I could prevent severe asphyxia in the baby, then we would prevent
neurologic injury. That would be nice if asphyxia were the major or
significant cause of neurologic injury during labor. Global asphyxia means
that the whole baby is asphyxiated and it gets progressively worse and
worse and is probably an extremely uncommon cause of injury during labor.
A more likely explanation for neurologic problems is that they are
obtained not only during labor, but also before, and are transient
interferences with blood flow. It is from these transient ischemic events
which the baby may recover the ability to survive, on the one hand, but
not recover the ability to be free from neurologic injury. So we've had to
learn something about how babies get injured to be able to use the monitor
appropriately. Having said that, the way the monitor does work
beneficially is, one, as I said, it lowers the death rate, and two, it
really does something which, in fact, keeps the baby out of harm's way and
that is very, very true."
Barbara
Nesbitt: "Would
this be for cerebral palsy?"
Dr.
Barry Schifrin:
"Yes, and not only for cerebral palsy, but the risk of death as well.
For example, as a general principle, we restrict potentially compromising
techniques to the demonstratively normal baby. So before you give oxytocin
or use an epidural, and before you even begin to think about an induction
of labor, you ask yourself, 'is the baby all right or do I have to do
something for the baby before I consider these other things?' That's what
monitoring does best - it keeps you from beginning a course of action,
such as induction or augmentation of labor, and it restricts those
activities to essentially the demonstratively normal baby. This is the
thing that the monitor does best, and it does it better than anything else
that exists. In terms of the definition of normal, by 'normal' I mean not
only the baby who has no problem with oxygenation, but also the baby who
is almost certainly neurologically normal because the heart rate pattern -
not the heart rate, but the heart rate pattern - is the end organ for not
only the heart, but the brain as well."
Barbara
Nesbitt: "Let's
say you have a woman comes in to the labor and delivery room, she's put on
the fetal monitor, and she gets an epidural. I think there's a lot of
controversy about epidurals, and I think we all know that if they're given
too early there is a problem. I was trained so that if it was at 5 cm,
then it was all right. So if somebody did have a problem, the fetal
monitor was going to pick that up, right?"
Dr.
Barry Schifrin:
"It will pick up a problem if there is one before the epidural, and
tell us 'maybe you should not give this epidural, which has potential
complications of its own.' Depending upon how the epidural is given and
how much lowering of the blood pressure may occur in response, the baby
will respond. It is unheard of that a baby who is becoming hypoxic or
suffering from diminished blood flow will not fail to respond. There's no
evidence of that. If there's a problem with fetal monitoring in terms of
its pitfalls, it's that there are too many abnormal heart rate patterns
and not all of them signify significant problems in the baby. The baby
simply has too many resources in terms of what it can do with its heart
rate to scare you, and it is an understanding of what is significant and
what is not that relates to the education about fetal monitoring. But the
issue of labor is separate, you see, from the issue of the appropriateness
of epidural at a certain amount of progress in labor, and a certain amount
of uterine activity..."
Barbara
Nesbitt:
"That's for the mother?"
Dr.
Barry Schifrin:
"That's for the mother and that's for the labor. Remember, the fetal
monitor is only asking one and a half questions. It says 'you see this
contraction? How did you like that one?,' and then it goes to the next
contraction and asks the baby how it likes that one, and so that is the
way it works. It simply goes from contraction to contraction and asks,
'for this number of contractions, for this frequency and aptitude of
contractions, how are you doing?' It doesn't tell you whether it's a good
idea or not a good idea to do an epidural, other than the baby is okay and
tolerating the amount of stress that this amount of uterine contractions
have depressed upon it."
Barbara
Nesbitt: "So
the fetal monitor treats the fetus and the…"
Dr.
Barry Schifrin:
"It doesn't treat."
Barbara
Nesbitt: "But I
mean, it's monitoring the unborn child, where the epidural is for comfort
for both the mother…"
Dr.
Barry Schifrin:
"But that's an obstetrical consideration, as opposed to a fetal
consideration. Remember, with the fetal monitor, what we are doing is
taking information - essentially end organ response information - directly
from the fetus itself, and that is the great virtue of what it is. It is
not a secondary or indirect parameter. It is, in fact, a primary."
Barbara
Nesbitt: "You
mentioned something about the ABCs of fetal monitoring. Tell us about
this."
Dr.
Barry Schifrin:
"The A is not from ABC, the way I refer to it, and it is not meant to
be referred to any basic notion of monitoring or even the beginning of the
alphabet or something as simple as that. The A stands for asphyxia,
anaerobia, hypoxia, and what have you. The B stands for behavior, or what
we're able to see on the fetal monitor and the fetal monitor patterns in
which we are able to understand fetal behavioral patterns. The C is for
the courage to believe A and B. Babies, for example, can not be
asphyxiated but have abnormal behavior even to the point of injury or
anomaly without being asphyxiated. Babies can be hypoxic but have their
nervous systems still working and compensating for that without injury.
The way you need to evaluate a pattern is from those two different
perspectives. Do I have a baby where there is a potential problem with
oxygen, and do I have a baby where there is a potential problem with its
neurologic control over its heart rate? Those are two independent
questions that cannot be answered by any single parameter. They can't be
answered by counting how many accelerations you have or by measuring how
big of an acceleration you have. They can't be answered by figuring out
how long they are, or simply by discerning how much variability you have.
What you need to do is to take both classes of information and synthesize
them to understand the question, 'how are you doing?' Before the advent of
fetal monitoring, that was not possible. The use of the stethoscope was
never designed to determine how the baby was doing. At its best
incarnation, it was only designed to be able to tell whether you had to
intervene or not, or whether it was necessary…"
Barbara
Nesbitt:
"Whether there was a heart beat to hear?"
Dr.
Barry Schifrin:
"Whether there was a problem or not, and whether to intervene. That's
very different from fetal monitoring. Fetal monitoring is here to tell you
- if you look at it properly - if you are doing all right, if you are
behaving yourself, if you are getting enough oxygen, and parenthetically,
if you have a burning desire to be someplace else. These are questions for
which the monitor is reasonably, but not infallibly, suited to
answer."
Barbara
Nesbitt: "So
the monitor is there to see if you have any problems at all. A woman goes
in to have a baby, finds she has no problems at all, but the monitor is
there in case she has them. Sometimes they might say, 'I don't know why I
needed one, I never had any problems.' But the monitor is there to pick up
the case that happens where nobody would have been able to do anything
about it quicker."
Dr.
Barry Schifrin:
"We've come to find that there are lots of things that you can do,
but you can't always prevent injury. This is what monitoring has helped us
understand. It has helped us understand that injury sometimes occurs so
rapidly that with a knife in your hand and a patient with a previously
normal tracing on the table, you would not be able to get the baby out
intact soon enough, even under those circumstances. Sometimes it happens
very quickly, and that is why one of the original pitfalls of monitoring
had to do with this notion of rescue, that a baby would have these
decelerations and we would rescue it. The fact is, sometimes you need to
do that if some catastrophic event occurs, but the notion of being able to
rescue, or being able to get in there soon enough to prevent injury under
any and all circumstances, is not a reasonable one. The monitors' great
role is not to essentially affect rescue, but to keep the babies out of
harm's way in the beginning."
Barbara
Nesbitt: "Very
good. Thank you very much, doctor. Do you have anything else you'd like to
add?"
Dr.
Barry Schifrin:
"Just to say thank you for the opportunity, and I'm happy to be
aboard."
Barbara
Nesbitt: "Thank
you, and welcome to OBGYN.net."
Dr.
Barry Schifrin:
"Thank you." |
