The clinical practice of auscultating fetal heart tones began in 1818 when a Swiss surgeon reported hearing the fetal heart rate by placing his ear against a pregnant woman’s abdomen. In 1888, an American physician, Dr. Killian, suggested that Fetal Heart Rate information could be used to identify the need for intervention for fetal distress. FHR was first introduced to the public by Yale in 1958 but did not become widely used in obstetric care until the 1970’s. Since then, it has become an accepted standard in the management of ob gyn patients who are in labor and close to delivery. Show
There are external and internal fetal monitors. External monitors (also known as ultrasound transducers) are usually composed of a belt with a doppler ultrasound that is strapped to the pregnant woman’s belly. Internal monitors consist of an electrode attached to the fetal scalp. The fetal membranes must be ruptured to apply an internal monitor. External monitoring is subject to loss of signal related to maternal positioning, fetal positioning, maternal body fat. A normal fetal heart rate range is 115-150 beats per minute (much faster than a normal adult heart rate). A slow heart rate, or bradycardia, may indicate the baby is not getting enough oxygen delivery to the brain. A fast heart rate, or tachycardia, may indicate oxygen deprivation. There is an acceptable range of acceleration and deceleration – or speeding up and slowing down – of fetal heart rates during contractions and labor. “Variable deceleration” or “late deceleration”, however, may be signs that the baby is not doing well. Variable decelerations are irregular dips in the fetal heart rate that may indicate cord compression, a potentially dangerous condition for the baby. Late decelerations begin with a uterine contraction and continue for too long after the contraction has resolved. This may be a sign that the baby is distressed. Obstetricians and nurses must carefully review fetal monitor strips throughout labor and delivery to ensure fetal heart tones are reassuring and the baby is getting enough oxygen. If non-reassuring conditions occur, appropriate and timely actions must be taken. Generally, nursing interventions are attempted first to restore normal oxygenation to the baby. These include the administration of supplemental oxygen, changes in maternal position, increasing intravenous fluids, and the administration of medications that subdue contractions and maximize placental blood flow. If fetal heart tones remain non-reassuring despite nursing interventions, the fetus should be delivered by emergency cesarean section. Emergency cesarean section should be performed within 5 to 30 minutes depending on the circumstances. It is hard to help a distressed baby in the uterus: a C-section is the best and fastest way to handle a baby in distress. Resuscitation, oxygen, fluids, and other lifesaving interventions may be quickly administered once the baby is born. This article is about how to monitor fetal heart tone of early, late, and variable decelerations during labor. I have been studying this in nursing school,and at first I thought this was very hard to understand. So for you I have broken it down by decelerations and simplified the reasons for why it is happening and what it looks like on the fetal heart monitor. I have been studying OB a lot lately mainly because I feel that is my weakest area for the NCLEX and HESI.I find OB super interesting and can’t wait to participate in the whole birthing process myself one day (which will be very far off in the future). Fetal Heart Tone Monitoring of Decelerations For Nursing Students and NursesIt truly is a beautiful process from conception to birth and thereafter. One of the coolest things about the labor process is the  For NCLEX and HESI, I think some of this stuff may be on there so I going to talk about the three main type of fetal heart tones that may be presented on these exams. Plus I find cardiovascular stuff interesting….remember my post on the EKGs lol and this deals with fetal heart tones. However, don’t get it confused with an EKG because the fetal heart tone monitor is just monitoring the heart rate of the baby not the heart rhythm…so don’t be looking for QRS intervals or ST waves on these strips lol. So here we go! Quiz & Video on Fetal Heart Tone DecelerationsAfter you read this article, be sure to take a Fetal Heart Tone Quiz and test your knowledge on these decelerations. Early DecelerationsThe picture above is known as an “early decelerations”. The top line is monitoring the baby’s heart rate and the bottom line is monitoring mom’s contractions. On the bottom line (mom’s contraction), you can see that the line start to go up and then down…….this means mom is having a contraction. The top line (baby’s heart rate) then responds to this contraction and notice that it slightly dips down while mom is having her contraction. The key to remembering if this an early deceleration is to see if the baby’s heart rate mirrors moms contraction and it does here. Plus look to see if the baby’s heart rate is staying within normal limits of 110-160 beats per minutes. The baby’s heart rate dips slightly at the same time the contraction starts and recovers to a normal range after mom’s contraction is over. Early decelerations are nothing to be alarmed about. The reason the baby’s heart rate starts to slightly decrease is due to head compression (probably from the baby’s head being in the birth canal) causing the vagus nerve to be compressed which in turn decreases the heart rate. So if you see this on NCLEX or HESI the answer to the question will probably be continue to monitor and document the process of the labor or no nursing interventions are required right now but continue to monitor. Variable DecelerationsThis crazy looking strip is called “variable decelerations“. I remember it because the dips in the fetal heart tones look like V’s. The v’s remind me that this is a “variable deceleration”. Variable decelerations are NOT good! Notice that every time mom has a contraction the baby’s heart rate majorly decreases. Remember a normal fetal heart rate is 110-160 bpms. The cause of the decrease fetal heart rate is due to umbilical cord compression. So if you are presented with this type of strip on NCLEX or HESI some of the answers you would need to pick would be change mom’s position (moving her around could help relieve cord compression), administer Oxygen usually 10 L (because cord is being compressed which in turn is causing the baby to not receive enough Oxygen), stop Picotin infusion if running, and contact the doctor. Plus you may be asked on the exam what is causing this strip to look like this and the answer would be cord compression. Late DecelerationsThe picture above is known as “late decelerations“. The name tells you exactly what should be presented on the strip. Late decelerations are NOT good either just like variable decelerations. Notice that when mom has a contraction the baby’s heart rate goes down long after the beginning of mom’s contraction and recovers way after the contraction is over. This is different from early decelerations because the baby’s heart rate went down at the same time the contractions happened and recovered to normal when the contraction ended. NCLEX and HESI may ask what is causing this type of strip and the answer would be uteroplacental insufficiency. Some nursing interventions include: turn mom onto her side, stop Picotin if infusing, administer 10 L of O2, maintain IV access, determine the Fetal Heart Rate variability, and contact doctor. By the way, kudos to the OB RNs out there! So there you have it….that was pretty much the down and dirty review of it! Cool huh lol!? I bet this type of monitoring has saved millions of baby’s lives because before this type of monitoring was invented you couldn’t have known if the baby was in distress during the labor. I hope this helps some of you NCLEX and HESI studying students. What is the priority action for late decelerations?The principal goal of management of late decelerations is to: Replenish uteroplacental blood flow by correcting the underlying cause. Increase fetal PO2. Prevention or correction of fetal acidemia.
How are late decelerations treated?These decelerations are completely benign as they do not affect fetal oxygenation and, therefore, do not require treatment. Late decelerations are caused by uteroplacental insufficiency, which is a decrease in the blood flow to the placenta that reduces the amount of oxygen and nutrients transferred to the fetus.
When considering fetal monitoring late decelerations are concerning and are caused by?Late decelerations are associated with uteroplacental insufficiency and are provoked by uterine contractions. Any decrease in uterine blood flow or placental dysfunction can cause late decelerations. Maternal hypotension and uterine hyperstimulation may decrease uterine blood flow.
Which is the most appropriate initial nursing intervention for late decelerations noted during the active phase of labor?CORRECT: The greatest risk to the fetus during late decelerations is uteroplacental insufficiency. The initial nursing action should be to place the client into the left-lateral position to increase uteroplacental perfusion.
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