Intrapartum Fetal Monitoring Flashcards
a full description of an EFM tracing requires both qualitative and quantitative assessment of
- uterine contractions
- baseline fetal heart rate
- baseline FHR variability
- presence of accelerations
- periodic or episodic decelerations
- changes / trends of FHR over time.
category 1
normal
category 2
indeterminate and require reevaluation, surveillance, and reevaluation
category 3
abnormal, require prompt evaluation and treatment, and mandate delivery if they do not resolve.
fetal heart rate acceleration in response to fetal scalp stimulation in presence of NRFH suggests
fetus may not be acidotic, but close surveillance should be continued.
FHR monitoring used to indirectly assess
fetal oxygenation
EFM has poor inter and intraobserver reliability and a high false-positive rate for detection of fetal compromise
true
uterine activity is a key component in the interpretation of EFM.
true
hyperstimulation and hypercontractility should be
ABANDONED
BASELINE must be for a minimum of 2 minutes in any 10 minute segment; if baseline for a segment cannot be determined, the PRIOR 10 minute segment should be used.
baseline must be for a min of 2 mins in any 10 min segment.
normal FH
110-160bpm
tachycardia
> 160bpm
bradycardia
<110bpm
baseline variability: absent
amplitude range undetectable.
minimal variability:
amplitude range detectable but <=5bpm
moderate (normal):
amplitude range 6-25bpm
marked;
amplitude range >25bpm
normal uterine activity
<= 5 contractions every 10 minutes averaged over 30 mins
tachysystole
> =5 contractions every 10 minutes . tachysystole applies to both spontaneous and induced labor. tachysystole should always be defined by presence or absence of fhr decelerations.
pattern: baseline
mean FHR to nearest 5bpm over 10 minute segment excluding periodic or episodic changes, periods of marked fhr variability, and segments of baseline that differ by >25bpm.
pattern: baseline variability
fluctuations in the baseline FHR that are irregular in implitude and frequency, quantitated as the amplitude of the peak to trough in bpm.
acceleration:
abrupt increase in FHR must reach peak in =32 weeks, accelerations must be >= 15bpm above baseline for >=15 seconds and =10bpm above baseline for >=10 seconds and <2 minutes from onset to return to baseline.
sinusoidal pattern
smooth sine wave-like undulating pattern in FHR baseline with a cycle frequency of 3-5/min that persists for >=20 mins.
late deceleration
symmetrical graduate decrease and return of FHR associated with a uterine contraction. a gradual FHR decrease is defined as fron onset to the FHR nadir of >= 30 seconds. the decrease in FHR calculated from onset to nadir of the deceleration. the deceleration is delayed in timing, with nadir of the deceleration occuring after the peak, and ending of the contraction, respectively.
FHR accelerations reliably predict
absence of fetal metabolic acidemia
absence of accelerations
does NOT reliably predict fetal acidemia
Moderate FHR variability reliably predicts absence of
fetal metabolic acidemia
Minimal or absent FHR variability
ALONE, does NOT reliably predict fetal metabolic acidemia or hypoxemia.
Category 1
- baseline rate 110-160bpm.
- baseline FHR variability: moderate
- Late/ variable decelerations: absent
- Early decelerations: present OR absent
- Accelerations: present or absent.
Cateogry II
all fHR tracings not categorized as Category I or CAtegory II. Examples: Bradycardia not accompanied by absent baseline varability; tachycardia. minimal baseline variability; absent baseline variability with no recurrent decelerations; marked baseline variability. Absence of induced accelerations after fetal stimulation. Recurrent variable decelerations accompanied by minimal / moderate baseline variability. prolonged deceleration >2 mins but
Cateogory III
either of the following: ABSENT baseline FHR variability AND any of the following: 1. recurrent late decelerations 2. recurrent variable decelerations 3. bradycardia. OR sinusoidal fhr pattern.
