NICHD Fundamental Principles (Nursing)

00:01 So here are the principles founded by the NICHD to help us determine how to read a strip.

00:08 Let's look at each one of those elements.

00:10 First, we're going to look at the baseline overtime.

00:14 So it's important when we look at the fetal monitor strip that we don't look at one minute we're going to look at 10 minute increments in order to make a quality interpretation.

00:23 So we're going to look at the variability or the change in fetal heart rate.

00:26 We're going to look for the presence of accelerations, so we do see an increase in the heart rate? We're going to look for periodic or episodic decelerations.

00:36 We're going to look for changes in that pattern over time, so what a pattern might look like at this hour, maybe very different from what it looks like in the next hour and what does that mean? We're going to have quantitative descriptions of the fetal heart rate tracing in terms of the numbers, like fetal heart rate and we're also going to look at the qualitative description of what it looks like in general. So these are the components.

00:59 I've thrown a lot of terms out, so let's break them down so we know what each one of those mean.

01:05 So the first component we're going to talk about is variability.

01:08 When you look at these strips, do you notice that the line at the top is smooth and the line at the bottom has more movement? What this is actually recording is the changes in the heart rate, so let's say for example, the heart rate on the top line is 150, that means that overtime, the heart rate stays pretty much 150, 150, 150, as opposed to the heart rate on the bottom where there's lot of variability and the heart rate maybe 150, 125, 175, and so that creates the change or the variability in the heart rate tracing.

01:47 Let's look a little bit closer.

01:49 So, the first line actually shows absent variability and if we're looking for a quantitative number, that means from the baseline, there's a change in the heart rate of only three beats, so if it's 150 it only goes between 150 and 153 or 150 and a 147, so not very much movement in the line at all, it's very smooth.

02:14 If we have minimal change, you see the line begins to become a little bit more bumpy.

02:20 So when we think about quantitative measure, the change maybe three to five beats from the baseline so plus or minus.

02:29 Moving on to moderate and this actually gets two categories because I want to really show you the wide variety of what a moderate heart rate could be, so the quantitative number is 5 to 25 beats and that's the difference from the baseline.

02:46 So moderate on the minimal side of moderate might be somewhere around five beats change and on the high side it might be as much as 25, so anywhere between 5 and 25 is good.

03:00 Then we have marked variability.

03:03 Now anyone with a cardiac background might say, you know what, that kind of looks like V-tach, and it does.

03:10 And V-tach is not good nor is marked variability, so we have greater than a 25 beat difference between the baseline heart rate and the tops and the bottoms of the heart rate tracing.

03:23 So I want you to think for a minute about which of these you might consider to be normal, absent, minimal, moderate, or marked? What do you think? Exactly, moderate is actually the only one that is normal.

03:44 Now we have quite a range of normal but it is the only one.

03:48 Marked, just like V-tach means there's some stress that's going on that's causing this tremendous variability.

03:54 If it's absent and it's smooth it might remind you of asystole which is never good.

03:58 It also is a sign of decrease oxygenation in the fetus, so that's not good.

04:04 Minimal is a little bit better than absent but not enough and that's why moderate is the only one that's normal, so we're looking for moderate variability that depicts a heart rate that goes 5 to 25 beats from the baseline. Got it? If you need a minute, go back and review that section and listen to it a couple of more times.

04:25 So now we're going to add a little bit more to what we've learned.

04:30 So let's look at this strip.

04:32 Again, to orient you, we're looking at the top box that looks at fetal heart rate tracing.

04:37 So the first thing we might do is figure out what the baseline heart rate is.

04:42 We're drawing that imaginary line through this fetal heart rate tracing to figure out what it might be.

04:48 It looks like it's about, I would want to say 148, but you know what? I can't, because baseline is always measured in 0 or 5 as an increment so I have to pick something that ends in a zero or five, so in this case I might want to say a 150 beats per minute is the baseline, okay? So now what I want you to do is to take out a piece of paper, if you got that, and I want you to look at the circles.

05:14 On the circles, I want you to look at what you think might be the fetal heart rate that is depicted there and right it down, so go ahead and do that.

05:29 Okay, so let's look at the first circle.

05:31 You may have come up with 155, so that's great.

05:36 On the second one we may have come up with 160 which is also great.

05:41 On the third one you may have come up with 165 which is also good, so that's going to be numbers that are going to help us determine whether or not these are accelerations.

05:53 The definition of an acceleration is a heart rate that goes at least 15 beats above the baseline for 15 seconds which is called 15 by 15 or 10 beats above the baseline for 10 seconds.

06:08 The difference has to do with the gestation of the fetus.

06:11 We use 15 by 15 for a fetus that's greater than 32 weeks gestation and 10 by 10 for a fetus that's less than 32 weeks gestation, and that make sense if you think about it because of the neurologic status of the fetus.

06:25 This line is generated because of the play between the sympathetic and parasympathetic nervous system which is all about neurologic maturity.

06:33 If we have a fetus that's over 32 weeks we're going to see more maturity, therefore we're going to have more fluctuation in that line.

06:41 If we have a fetus that's less than 32 weeks, it's going to be less neurologically mature and so there's going to be less play creating less dramatic kind of line changes, alright.

06:53 So what we see in the circles are examples of three accelerations based on our criteria.

07:00 Also, take a look at that variability.

07:04 Now that we know what it is, what would you call the variability of this line? Exactly, its moderate; and we know that moderate variability is good.

07:17 Alright, let's look at the contraction pattern again.

07:21 So just to orient you, this is the graph on the bottom and you remember that we're going to ignore that zero to five hundred number, we're only going to pay attention to the 0 to 100, that's going to tell us that we're looking at contraction pattern.

07:36 Also take a look at these hills, they're a little bit bigger than the ones on the top and that should also clue us in that we're looking at contraction pattern.

07:45 Now this is an external monitor, which means we can't really tell strength very well, so the only thing we're going to be able to use, is the measurement on the horizontal axis or time and what we're actually going to be able to tell is how far apart the contractions are and how long they last, frequency and duration.

08:04 Frequency actually is measured from the beginning of one contraction until the beginning of the next contraction.

08:11 So the contractions are measured by the hills, do you see them? So, we'll look at where the contraction starts, we'll count the little boxes all the way until the beginning of the next contraction.

08:23 Now, sometimes, at least at the beginning, I used to get confused and I would use to count the space in between, that's not correct.

08:32 We have to count from the beginning of one contraction to the beginning of the next contraction, and that's how we do frequency.

08:40 Next, let's look at duration.

08:42 Duration really speaks to how long the contraction lasts and it goes from the beginning of the contraction till the end of the contraction, that one is measured in seconds.

08:54 Frequency usually in minutes, duration usually in seconds.