FHR Monitoring II

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FHR Monitoring II
2014-02-20 17:13:41
fetal OB

Notes from webinar
Show Answers:

  1. Respiratory acidosis is caused by
    increase in CO2 in fetal blood stream hydrolized into carbonic acid. Little effect on base deficit and will return to normal if cord compression is resolved
  2. pCO2 and base deficit in metabolic acidosis
    pCO2 is low and base deficit is high
  3. Variable decel characteristics
    • abrupt: onset to nadir in less than 30 seconds
    • decrease is greater than or equal to 15 beats per minute
    • lasts greater than or equal to 15 seconds but less than 2 minutes
    • Category III if absent variability and recurrent
  4. Cause of variable in early labor
    • Low fluid.
    • Solution=amnioinfusion
  5. Cause of variable in second stage
    Cord compression associated with descent
  6. Sudden onset of deep variable makes you think:
    Cord prolapse
  7. Fourth category of unusual cord conditions
    short or knotted cords or cords around body parts
  8. What to do with variable decels
    • 1. Shift positions
    • 2. provide oxygen if hypoxemia is occurring
    • 3. amnioinfusion
  9. Mechanism of variable decel
    1. Umbilical arterial occlusion-----fetal htn-----fetal baroreceptor stimulation------central vagal stimulation-------FHR decel

    2. Umbilical arterial occlusion-----fetal hypoxemia------fetal chemoreceptor stimulation--------central vagal stimulation----FHR decel  (could have hypoxemic myocardial depression)
  10. Def of prolonged decel
    • 1. Greater or equal to 15bpm, lasting greater than or equal 2 min
    • 2. Shorter than 10 minutes
  11. Cause of prolonged decel
    • Profound uteroplacental insufficiency
    • Hypotension in the supine position
    • epidural anesthesia
    • cord compression, cord prolapse, abruption  (often following recurrent variable decels)
  12. Recovery of prolonged decels
    • 1. May be followed by rebound tachycardia with no variability
    • 2. As long as initiating event is resolved and fetus was well oxygenated prior to event, placenta will reoxygenate uterus
    • 3. If decel does not have treatable etiology and not resolved within 5-7 minutes, immediate intervention may be indicated
  13. Single most important indicator of immediate fetal status
  14. Absence of variability indicates
    decrease in central nervous system function
  15. Most worrisome possible cause for decrease in variability
    acidosis caused by hypoxia
  16. Acidosis in fetus unlikely to be present unless....
    no variability + decels (recurrent late, recurrent variable or bradycardia)
  17. Place this in a stalled labor
  18. Doppler ultrasound can detect fetal heart rate in this range
    50 to 180
  19. Number of hours to delay pit after cytotec given for induction
    • 4
    • 6 is better