Fetal surveillance - IPM abnormalities Flashcards
1
Q
Examples of abnormalities
A
- Decelerations
- Sinusoidal pattern
- Tachysytole
2
Q
General types of decelerations
A
- Gradual
- Early
- Late
- Abrupt
- Variable
3
Q
Gradual versus abrupt deceleration
A
- Gradual
- Onset to nadir ≥ 30 secondsm(calculated from the onset of the nadir to the return
- Abrupt
- Onset to nadir < 30 secondsm(calculated from the onset of the nadir to the return
- Both
- Transient episode of slowing of FHR below the baseline more than 15 bpm
4
Q
Early deceleration
- Definition
- Cause
- Mechanism of cause
A
- Definition
- Gradual onset
- Onset of deceleration occurs at the onset of contraction
- Cause
- Fetal head compression
- Mechanism of cause
- Head compression → increased ICP → vagal nerve innervation
5
Q
Late deceleration
- Definition
- Cause
- Mechanism of cause
A
- Definition
- Gradual onset
- Deceleration occurs after the peak of contraction (time delay of more than 15 seconds after contraction)
- Cause
- Uteroplacental insufficiency
- Mechanism of cause
- Uteroplacental insufficiency → decrease U-P O2 transfer → chemoreceptor stimulus → vagal nerve stimulation → deceleration
6
Q
Variable deceleration
- Definition
- Cause
- Mechanism of cause
A
- Definition
- Abrupt onset
- Occurs anytime in the contraction
- Cause
- Cord compression
- Mechanism of cause
- Occlussion of vein → reduced fetal blood return → deceleration
7
Q
What is prolonged deceleration?
A
Decrease in FHR from the baseline is ≥ 15 bpm, lasting ≥ 2 minutes but < 10 minutes in duration
8
Q
At what cervical dilation does early deceleration usually occur?
A
4–7 cm
9
Q
Sinusoidal pattern
- Definition
- Causes
A
- Definition
- Visually apparent, smooth, sine wave-like undulating pattern in FHR baseline with a cycle frequency of 3-5 bpm which persists for ≥ minutes
- Causes
- Severe fetal anemia or tissue hypoxia in fetal brain stem
- Fetal intracranial hemorrhage
- Severe fetal asphyxia
- Rh alloimmunization
- Fetomaternal hemorrhage
- Twin-twin transfusion
- Vasa previa with bleeding
- Severe fetal anemia or tissue hypoxia in fetal brain stem
10
Q
Causes of pseudosinusoidal heart rate
A
Nubain, Mepiridine, Morphine, Alphaprodine, Butorphanol (Stadol)
11
Q
What is tachysystole?
A
> 5 contractions in 10 minutes (averaged over 30 minutes window)
12
Q
Categories according to the three tier system
A
- Category I
- Normal tracing
- Category II
- Intermediate tracing
- Category III
- Abnormal tracing
13
Q
Category I tracing criteria
A
- Baseline
- 110-160
- Variability
- Moderate
- Decelerations
- Absence of late or variable decelerations
- Early decelerations may or may not be present
- Accelerations
- May or may not be present
14
Q
Category II tracing criteria
A
- Baseline
- Tachycardia
- Bradycardia (not accompanied by absent baseline variability)
- Variability
- Minimal baseline variability
- Absent baseline variablity not accompanied by recurrent deceleration
- Marked baseline variability
- Deceleration
- Periodic or episodic deceleration
- Recurrent variable decelerations accompanied by minimal or moderate baseline variability
- Prolonged deceleration ≥ 2 minutes but < 10 minutes
- Recurrent late decelerations with moderate baseline variability
- Variab;e decelerations with other characteristics, such as slow return to baseline, ‘overshoots,’ or ‘shoulders’
- Periodic or episodic deceleration
- Acceleration
- Absence of acceleration after fetal stimulation
*
- Absence of acceleration after fetal stimulation
15
Q
Category III tracing criteria
A
- Absent baseline FHR variability along with any of the following:
- Recurrent late deceleration
- Recurrent variable deceleration
- Bradycardia
- Sinusoidal pattern
