Fetal Heart Rate Monitoring Flashcards
(84 cards)
1
Q
when are late decels considered “ominous”?
when are they considered severe?
A
- ominous if accompanied with lack of variability
- severe if decreased more than 45 bpm
2
Q
what is minimal vs. marked FHR variability?
(book)
A
- minimal - amplitude range of 5 bpm or less
- marked - amplitude range of > 25 bpm
3
Q
what type(s) of decels require urgent assessment of fetal status
A
late and variable
4
Q
early decels and risks of hypoxia?
A
no risk of fetal hypoxia
5
Q
what do antepartum accelerations correlate with?
A
- fetal movement
- accelerations = happy bebe
- book: ensures absence of fetal acidosis or hypoxemia, providing reliable reassurance of fetal well-being
6
Q
how do CNS depressants given to mom generally impact the bebe?
(book)
A
decreased FHR variability
7
Q
what three categories qualify a patient as a high-risk pregnancy?
A
- medical complications
- fetal complications
- intrapartum complications
8
Q
what it this and what can cause it
A
early decel
head compression
9
Q
what two factors have an impact on the intrinsic fetal heart rate
A
- neuronal
- humoral
10
Q
normal baseline FHR
what is baseline FHR? (book)
A
110-160 bpm
baseline FHR is determined as the mean FHR rounded to 5bpm during a 10-minute period that has no accelerations, decels, or marked variability
11
Q
what type of variability is seen in this shitty picture from the book
A
marked
12
Q
what do late decels usually indicate?
(book)
A
uteroplacetal insufficiency
13
Q
causes of prolonged decels
(book)
A
- uncorrected maternal hypotension
- maternal supine position
- uterine hyperstimulation
- prolapsed cord
- cord entanglement
- uterine rupture
- placental abruption
14
Q
examples of fetal complications that indicate high risk pregnancy (6)
A
- IUGR
- nonlethal anomalies
- prematurity
- multiple gestations
- postdatism (?)
- hydrops
15
Q
what device measures pressures inside the uterus?
A
intrauterine pressure catheter
16
Q
what can variable decels indicate?
A
- vagal activity
- umbilical cord occlusion (partial or complete, or occlusion from short cord stretching)
17
Q
what type of receptor responds to an increase in BP in the fetus?
what type responds to decreased PaO2 and increased PaCO2?
A
- BP - baroreceptors
- CO2 - chemoreceptors
18
Q
what interventions will correct most cases of fetal bradycardia before an expedited c section is necessary?
(book)
A
prompt treatment of hypotension and uterine overactivity
19
Q
what is a sinusoidal FHR pattern and what does it look like?
causes?
(book)
A
- cycle frequency of 3-5/minute and amplitude of 5-15 bpm which persists 20+ min
- smooth, sine, wave-like, undulating pattern (tbh looks like v tach)
- strongly predictive of fetal asphyxia
- also - fetal anemia, occasional maternal opioid use
20
Q
what questions would you address when determining if an epidural is adequate for use in c-section?
A
- is it patchy?
- will the patient/fetus tolerate additional LA to achieve adequate level?
- how quickly can adequate level be achieved?
- what is the probability of block failure?
- would a SAB behoove the situation? would it make things worse?
21
Q
how does an external FHR transducer use doppler ultrasound
what is an alternative to this?
A
detects changes in ventricular wall motion and blood flow through major vessels
alternative - scalp ECG lead to measure R-R interval
22
Q
what can early decels indicate?
A
head compression
23
Q
what is an acceleration and how long does it last?
A
- abrupt change in fetal heart rate above baseline
- Per book- >15 bpm if 32 weeks and 10 if < 32 weeks
- at least 15 beats above baseline for at least 15 seconds
24
Q
what is a saltatory FHR pattern?
what can cause it?
what is it weakly associated with in the fetus?
A
- excessive alterations in variability
- caused by acute fetal hypoxia
- weak association to low Apgar scores
25
how can regional anesthesia impact the baby
(book)
maternal hypotension is a common complication of neuraxial labor analgesia→ can lead to decreased uteroplacental perfusion, fetal hypoxemia, and fetal decels
decels can occur w/o maternal hypotension esp. with spinals
26
developing countries have what percent of intrapartum stillbirths?
developed countries have what percent of intrapartum stillbirths?
* developing: up to 50%
* developed: up to 10%
27
what is this and what is it associated with
variable decel
umbilical cord compression
28
examples of intrapartum complications that indicate high risk pregnancy (4)
- bleeding
- maternal fever
- meconium-stained amniotic fluid
- oxytocin augmented labor
29
what does an IUPC measure?
* strength of contractions
* precise onset and offset of each contraction
30
do external FHR monitoring and scalp ECG monitor the fetal heart rate intermittently or continuously?
continuously
31
a normal variability in fetal heart rate indicates what reassuring things?
intact fetal...
- cerebral cortex
- midbrain
- vagus nerve
- cardiac conduction system
32
examples of medical complications that indicate high risk pregnancy (5)
- HTN
- pre-eclampsia
- diabetes
- autoimmune disease
- hemoglobinopathy
33
what is the name of the device that externally measures contractions while sitting on the fundus?
what information can this device provide? (book)
tocodynamometer
reveals timing and frequency of contractions - **not** contraction strength
34
commonly seen when EFM is used for nonobstetric surgery
\*~clinical pearl~\*
loss of beat to beat variability
35
fetal monitoring simultaneously monitors what two factors?
combining these allows for what to be analyzed?
- fetal heart tones
- uterine contractions
- can determine baseline rate and pattern of FHR compared to uterine contractions
36
what is this insane looking thing
saltatoryFHR pattern (with wide variability)
37
timing and appearance of late decels
* occur with each uterine contraction
* uniform in appearance
* begin 10-30 sec after contraction begins and end 10-30 seconds after contraction ends
* vary in depth according to the strength of the correlating contraction
* gradual (not abrupt)
38
how does the addition of clonidine to dilute bupivacaine for neuraxial labor analgesia impact FHR?
(book)
shown to lower baseline FHR
39
does an abnormal FHR automatically mean fetal compromise?
tell me more
* nope - false positives are a thing
* abnormal FHR of prolonged bradycardia or late decels with absence of variability can indicate fetal compromise
40
what type of variability does this represent
normal
41
what qualifies as a normal pattern of contractions?
5 or less contractions in a 10 min period averaged over 30 min
42
what might minimal/absent variability **plus** decels indicate?
\*~clinical pearl~\*
concurrent or impending fetal hypoxemia and metabolic acidosis
43
how does GA affect the baby fetus?
(book)
* decreased maternal SNS output can cause maternal hypotension and diminished fetal O2 delivery
* CNS depressants/opioids cross placenta and depress fetal CNS
44
what qualifies as a tachysystole pattern of contractions?
more than 5 contractions in a 10 min period
45
what can late decels indicate?
uteroplacental insufficiency
46
when might accelerations occur?
| (book)
* fetal movement
* uterine contractions
* fetal manipulation/stimulation during pelvic exam
47
what is a prolonged decel?
| (book)
decels lasting 2-10 minutes
| (\>10 min considered change in baseline)
48
what immediately precedes and follows variable decels?
(book)
slight FHR acceleration
49
how does maternal Mg sulfate impact FHR?
when might this be given?
(book)
* decreased baseline FHR
* decreased variability
* no AEs for baby
* given to prevent seizures in preeclamptic moms
50
what does a scalp ECG measure?
R-R interval
51
term baseline FHR vs preterm baseline FHR
term babies have lower baseline FHR
52
what is this and what can cause it
late decel
uteroplacental insufficiency
53
how does admin. of magnesium for preeclampsia impact variability?
(book)
can cause decreased variability
54
what is this
sinusoidal FHR pattern
55
how does terbutaline impact FHR?
larger dose = significant increase in baseline FHR at 20 & 40 min
smaller dose = little effect
56
fetal PNS outflow effect on FHR
fetal SNS outflow effect on FHR
- PNS - decreases FHR
- SNS - increases FHR
57
if doing pre-anesthetic assessment and notice nonreassuring FHR monitor tracing, what should you consider?
- consider whether anesthetic intervention could worsen fetal status
- discuss with OB
58
why is it important to maintain mom's CO and treat promptly when decreased?
(book)
decreased CO = decreased uterine blood flow
59
describe the timing and appearance of variable decels
* vary in depth, shape, and duration
* abrupt onset and offset
* book - abrupt increase in FHR \> 15+ bpm
* book - lasts from 15 seconds - 2 minutes
60
late decels and risks of hypoxia?
- risk for fetal hypoxia
- requires urgent assessment of fetal status
61
when are decels considered recurrent vs. intermittent?
(book)
prolonged - occur with ≥ 50% of contractions during a 20 minute period
intermittent - \< 50%
62
how long is a prolonged acceleration?
what would it be if it were longer than that?
- prolonged acceleration is \> 2 minutes of 15 beats above baseline
- if acceleration lasts \> 10 minutes it's considered a change in baseline
63
what do accelerations preclude?
\*googles preclude\*
preclude the existence of fetal metabolic acidosis
64
why should you be cautious about glycopyrrolate admin. to a pregnant mom?
(book)
can cause significant fetal bradycardia
interesting since we learned that it doesnt readily cross the placenta
65
what is the purpose of electronic FHR monitoring?
(book)
detect signs of fetal response to hypoxemia and acidosis (decreased movement, tone, breathing, FHR, variability)
66
what type of variability is this
idk why there are such shitty pictures in the book
minimal
67
what type of fetal HR monitoring allows for more movement and ambulation of the momma?
telemetry
this is hella dumb
68
what causes fetal tachycardia seen with prolonged exposure to hypoxia?
catecholamine secretion and SNS activity
69
high-risk mothers make up percent of the pregnant population?
these babies make up what percent of perinatal morbidity and mortality?
- make up 20% of population
- 50% of m&m cases
70
what does the tocodynamometer approximate?
onset, duration, and offset of contractions
\*not\* contraction strength
71
if it is determined that an emergent c-section is necessary, what do we need to evaluate for?
evaluate for if epidural is already in place, and if so, if it can be adequately dose and utilized for a cesarean
72
what measurements are given with an intrauterine pressure catheter
what population is this device reserved for? (book)
measures exact pressures in the uterus
quantitative measurement of uterine contraction **strength** (book)
Only used when membranes are ruptured
73
describe the timing, HR, and appearance of early decelerations
* gradual decline in HR (usually \< 20 bpm below baseline)
* occur simultaneously with uterine contractions
* uniform in appearance
74
variable decels and risks of hypoxia?
- risk for fetal hypoxia
- requires urgent assessment of fetal status
75
what type of variability is this
absent
76
how does maternal use of beta-blockers impact the baby?
(book)
long term use assoc. with fetal bradycardia, hypoglycemia, and FGR
77
tell me about the predictability of electronic fetal heart rate monitoring
- it is not a specific predictor of fetal well being
- still being used because there is no optimal yet practical method that has been developed
78
how does maternal betamethasone impact FHR?
when might this be given?
(book)
* 1st day of admin: decreased FHR, increased variability
* 2-3rd day: increased FHR, decreased variability
* given to make preemie bby lungs better
79
what else can change the baseline fetal heart rate besides hypoxia? (4)
* anatomic or functional heart pathology
* maternal fever
* intrauterine infections
* maternally administered medications --- beta-agonists (terbutaline) or anticholinergic (atropine)
* can be a normal variant (book)
80
what do normal/moderate fluctuations in FHR indicate?
(book)
per MBG - "good"
per book - excellent predictor of the absence of fetal metabolic acidosis
81
if we see changes in the FHR monitor, what is our ultimate goal as a CRNA?
- goal: rule out anesthetic intervention as the cause
- if it is related to anesthetic - correct hypotension (#1 suspect)
- if epidural level higher than necessary, let it recede
82
interventions for nonreassuring FHR patterns
(book)
* maternal O2 via face mask - increase maternal alveolar O2 tension
* optimize maternal CO - IV bolus, vasoactive drugs, uterine displacement
* increase uterine perfusion with a direct alpha agonist (phenylephrine), IV bolus, d/c oxytocin, uterine displacement, or terbutaline
83
T/F - early decels are associated with fetal hypoxia, acidosis, and low Apgar scores
(book)
false
84
fetal response to hypoxia?
initially bradycardia
tachycardia with prolonged hypoxia
