Fetal surveillance - IPM abnormalities Flashcards Preview

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Flashcards in Fetal surveillance - IPM abnormalities Deck (16):
1

Examples of abnormalities

  • Decelerations
  • Sinusoidal pattern
  • Tachysytole

2

General types of decelerations

  • Gradual
    • Early
    • Late
  • Abrupt
    • Variable

3

Gradual versus abrupt deceleration

  • 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

Early deceleration

  • Definition
  • Cause
  • Mechanism of cause

  • 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

Late deceleration

  • Definition
  • Cause
  • Mechanism of cause

  • 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

Variable deceleration

  • Definition
  • Cause
  • Mechanism of cause

  • Definition
    • Abrupt onset
    • Occurs anytime in the contraction
  • Cause
    • Cord compression
  • Mechanism of cause
    • Occlussion of vein → reduced fetal blood return → deceleration

7

What is prolonged deceleration?

Decrease in FHR from the baseline is ≥ 15 bpm, lasting ≥ 2 minutes but < 10 minutes in duration

8

At what cervical dilation does early deceleration usually occur?

4–7 cm

9

Sinusoidal pattern

  • Definition
  • Causes

  • 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

10

Causes of pseudosinusoidal heart rate

Nubain, Mepiridine, Morphine, Alphaprodine, Butorphanol (Stadol)

11

What is tachysystole?

> 5 contractions in 10 minutes (averaged over 30 minutes window)

12

Categories according to the three tier system

  • Category I
    • Normal tracing
  • Category II
    • Intermediate tracing
  • Category III
    • Abnormal tracing

13

Category I tracing criteria

  • 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

Category II tracing criteria

  • 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'
  • Acceleration
    • Absence of acceleration after fetal stimulation
  •  

15

Category III tracing criteria

  • Absent baseline FHR variability along with any of the following:
    • Recurrent late deceleration
    • Recurrent variable deceleration
    • Bradycardia
  • Sinusoidal pattern

16

Resuscitative measures

  • Put the patient on a left lateral decubitus position
  • Oxygen support
  • Discontinue oxytocin
  • IVF bolus (200cc)