Easy explanations needed....

sweetcheekers · Aug 18, 2005

since I'm just a new grad myself, but .... Variability itself is a good thing. It will look like a sawtooth type line on a strip. Variability is said to be a reassuring sign as it is evidence of the babies heartrate responding to various stimuli (contractions and the break between them). I assume short term variability is when there is some evidence of variability but it is not lasting long enough to be "reassuring". Decelerations are normal to see on a strip, the type is determined by comparing them to the contraction pattern. My understanding is that an early deceleration is where the heart rate decrease (you see a drop on the strip) ends before the contraction ends. A late decel on the other hand is when the drop in heart rate lasts LONGER than than the contraction. This is BAD if it persists because it indicates that the baby is not recovering adequately between contractions and it could be that there is another source of stress besides the contractions (like cord around the neck). It indicates that the baby is not getting adequate oxygenation. That's about all I remember. I should brush up though because I have an interview Monday for a busy OB department position. Thanks for making me think. OB/Peds was a long time ago.:)

SmilingBluEyes · Aug 18, 2005

I have done a search on these topics, but didn't get as much info as I wanted, and it seems that the topic hasn't been touched on in a while.
Can anyone easily explain the following:
Short term variability
Long term variability
Late decelerations
Early decelerations
I'm reading it in my text, but it's just not making sense to me of what it looks like clinically.
Any help would be fabulous!!
Thanks,
Amy

Short term variability : Also known as "beat- to- beat" variability, denotes literally, the changes in heart rate from beat to beat. Only really useful to assess if internal monitor (fetal spiral electrode) is used to measure FHR.

Long term variability: the changes in fetal heart rate over minutes, and hours.....A heart rate is said to be "reassuring" if there are "accelerations" in it----meaning an increase of FHR of 15 beats per minute for no less than 15 seconds. Decreased or absent variability denotes little to no acceleration in heartbeat. This is ok ----if limited to short periods of about 30 min to an hour. Usually, you will see decreased variability during fetal sleep patterns. Longer terms of decreased or absent variability indicate further investigation and prompt reporting to the care provider.

Late Decelerations: These occur during, but end AFTER, a contraction has ended. Please note: You cannot assess the TYPE of deceleration it is, unless you have a reading of uterine contractions (toco).

The "late" ends AFTER the contraction is over. It requires further assessment, investigation and possibly, some intrauterine resuscitation, such as fluid volume replacement, Oxygen by mask and a change in maternal positioning. Often, cord compression and/or decreased placental functioning are the causes of "lates". Another possible cause is decreased amniotic fluid volume----or poor oxygenation/neuro functioning of the fetus. Un-resolved 'lates" need to be reported to the care provider promptly.

There a couple of other "decels" you may see:

The "variable decel" "mirrors" the uterine contraction in timing and nadir (peak). It looks like a "v" on the tracing. It often occurs due to cord compression during a contraction. Severe variable decels may be treated with a change in maternal position or fluid resuscitation/supplemental oxygen. They bear watching. If they get worse, or are slow to recover, they need to be reported to the care provider. These decels drop in heart quickly, and resolve just as quickly, hence the "v" shape on your tracing. They are more reassuring if they occur in the presence of average/normal long term variability.

An "early decel" occurs during, but always ends, before the contraction does. An "early" with normal variability is reassuring; it usually denotes descent of the fetal presenting part----the fetus "vagals" a bit as the head is compressed, so the heart rate lowers a bit---but it recovers to normal baseline as the contraction ends, ending the vagal response. It is almost always benign in nature.

Remember, assessing/monitoring variability is one tool used to ascertain likely oxygenation and neurologic functioning of the fetus. Absence of any variability (accels) always begs further investigation. So do drastic changes in overall baseline in fetal heart rate---if you started with a baseline of 120-130 and later, it becomes more like 170 or so, and does not come back down, this may indicate maternal infection/fever, or fetal distress.

Bradycardias (below 110 BPM) also should be watched/investigated---if the baby 's baseline was previously over this. Or if very low (below 100BPM, may indicate heart block in the fetus)..... It's a bit complicated, I know....but I hope I helped here.

SmilingBluEyes · Aug 18, 2005

Good job, there, Sweetcheekers!

INFJ · Aug 19, 2005

Thank you both so much for responding...and for making it seem more "real".

I printed both responses so I can read and re-read them and get a good grasp before I go to OB clinical in 2 weeks!

Good luck Sweetcheekers on your OB interview. I would love to hear how it goes and what types of questions you are asked. I started out Nursing school wanting to do Oncology...but the more I delve into L & D and baby stuff the more I fall in love....hmm, maybe NICU??

Thanks again guys!!!!

Amy :)

lionkore · Aug 20, 2005

to the OP, thanks for asking a question that I also needed to ask, but hadn't formulated yet. :)

Short term variability : Also known as "beat- to- beat" variability, denotes literally, the changes in heart rate from beat to beat. Only really useful to assess if internal monitor (fetal spiral electrode) is used to measure FHR.
Long term variability: the changes in fetal heart rate over minutes, and hours.....A heart rate is said to be "reassuring" if there are "accelerations" in it----meaning an increase of FHR of 15 beats per minute for no less than 15 seconds. Decreased or absent variability denotes little to no acceleration in heartbeat. This is ok ----if limited to short periods of about 30 min to an hour. Usually, you will see decreased variability during fetal sleep patterns. Longer terms of decreased or absent variability indicate further investigation and prompt reporting to the care provider.
Late Decelerations: These occur during, but end AFTER, a contraction has ended. Please note: You cannot assess the TYPE of deceleration it is, unless you have a reading of uterine contractions (toco).
The "late" ends AFTER the contraction is over. It requires further assessment, investigation and possibly, some intrauterine resuscitation, such as fluid volume replacement, Oxygen by mask and a change in maternal positioning. Often, cord compression and/or decreased placental functioning are the causes of "lates". Another possible cause is decreased amniotic fluid volume----or poor oxygenation/neuro functioning of the fetus. Un-resolved 'lates" need to be reported to the care provider promptly.
There a couple of other "decels" you may see:
The "variable decel" "mirrors" the uterine contraction in timing and nadir (peak). It looks like a "v" on the tracing. It often occurs due to cord compression during a contraction. Severe variable decels may be treated with a change in maternal position or fluid resuscitation/supplemental oxygen. They bear watching. If they get worse, or are slow to recover, they need to be reported to the care provider. These decels drop in heart quickly, and resolve just as quickly, hence the "v" shape on your tracing. They are more reassuring if they occur in the presence of average/normal long term variability.
An "early decel" occurs during, but always ends, before the contraction does. An "early" with normal variability is reassuring; it usually denotes descent of the fetal presenting part----the fetus "vagals" a bit as the head is compressed, so the heart rate lowers a bit---but it recovers to normal baseline as the contraction ends, ending the vagal response. It is almost always benign in nature.
Remember, assessing/monitoring variability is one tool used to ascertain likely oxygenation and neurologic functioning of the fetus. Absence of any variability (accels) always begs further investigation. So do drastic changes in overall baseline in fetal heart rate---if you started with a baseline of 120-130 and later, it becomes more like 170 or so, and does not come back down, this may indicate maternal infection/fever, or fetal distress.
Bradycardias (below 110 BPM) also should be watched/investigated---if the baby 's baseline was previously over this. Or if very low (below 100BPM, may indicate heart block in the fetus)..... It's a bit complicated, I know....but I hope I helped here.

smiling blue eyes, once again I am in in awe of your knowledge. I just wanted you to know how much I appreciate your posts, they are incredibly helpful to me as I start my journey in L&D (today was my 2nd day of orientation).

thank you! :balloons:

kori