Fetal Heart Sounds Flashcards
3 reasons that support the use of FHM?
Reassurance, greater than 98% that good fetal outcome is associated with FHM
Too expensive for 1:1 auscultation
The monitoring can be a warning of problems and gauge fetal responses as well
What is normal fetal oxygen reserve? What happens during uterine contraction that has an effect on placental exchange?
1-2 minutes of reserve
Exchange through the placenta is interrupted during uterine contraction.
What do the upper and lower tracings monitor in the fetal strip?
Upper is fetal HR
Lower is uterine contraction
What is considered normal uterine contraction activity and what is considered tachsystole?
5 contractions or less in 10 minutes averaged over 30 minute period
Greater than 5 contractions in 10 minutes averaged over 30 minute period
What is normal Intra uterine pressure or better, what does it need to be to progress to labor? How are we measuring it?
Over 200 in a ten minute period. IUPC.
Summing up the pressures of contractions in a ten minute period. Do this for 2 hours.
What is normal, tachycardia, and bradycardia for fetal HR?
110-160
Greater than 160
Less than 110
How do we get a baseline FHR?
Average rounded to increments of 5bpm over ten minute period in between contractions
6 causes of bradycardia in baby?
Hypoxia, late Anesthesia Mother is hypotensive Compression of umbilical cord Pitocin Heart block
6 causes of tachycardia and which one is most common?
Early phase of hypoxia Too much pitocin Arrhythmias Prematurity Maternal fever Infection most common
How do we define baseline variability, what are the 4 types and how do we define the types?
Distance of peak and trough from baseline. Absent - nothing Minimal - less than 5 bpm Moderate - 6-25 Marked - greater than 25
Decreased variability is associated with what?
Hypoxia and acidosis causing CNS and HR depression
6 causes of decreased variability
Prematurity, mom has fever, tachycardia, congenital anomalies, mom is hyperthyroid, and mom doing drugs.
Explain normal fetal HR accelerations and when they occur?
Greater than 32 weeks, 15 above baseline for 15 seconds
Less than 32 weeks, 10 above baseline for 10 seconds
What is considered prolonged acceleration and when do we see we have a change in baseline?
Acceleration greater than 2 minutes
Greater than 10 minutes
3 causes of accelerations?
Spontaneous fetal movement
Scalp or vibroacoustic stimulation
Vaginal exam
What is the cause of early decelerations and what do we see on the fetal strip?
Fetal head compression
The trough mirrors the contraction
What is the cause of variable deceleration, what will we see on the fetal strip and what is acceptable for the time the FHR is depressed?
Compression of umbilical cord.
Can decrease before, during or after contraction
Can decrease greater than 15 bpm, for 15 seconds, but less than 2 minutes.
What is going in physiologically and on the fetal strip during the phenomenon they call shoulder?
Umbilical vein is compressed which carries the oxygenated blood to baby heart. This will be a slight increases in HR followed by a major drop.
What is the cause of late decelerations and what do repetitive late decelerations means?
Uterine placental insufficiency, either by maternal hypotension or excessive uterine activity.
Baby is hypoxic and acidosis
What is the cause of prolonged deceleration and what does the fetal strip show?
Disruption of oxygen transfer to fetus, commonly seen during maternal pushing.
Greater than 15 bpm decrease over 2 minutes.
What does the fetal strip show for fetal anemia?
Sinusoidal
Let’s say tracing shows recurrent variable decelerations with greater than 50 % of contractions, what is the problem and what 3 things to treat?
Umbilical cord compression
Reposition, Modify how mom is pushing, amnioinfusion
What is amnioinfusion?
Infusion of normal saline can alleviate cord compression
What is the goal to treat tachysystole in baby?
Reduce uterine activity
