Labor 2 powerpoint

How does FHR work relative to oxygenation

The fetus gets all of its oxygen from the mother through the placenta. When oxygen delivery drops, the fetus compensates by increasing its heart rate to raise cardiac output, since it can’t increase stroke volume much. Accelerations usually happen with fetal movement when the sympathetic nervous system kicks in, and they’re a good sign that the fetus is well oxygenated. Decelerations happen when the vagus nerve gets stimulated and slows the heart

What are the output pathways of the Cardioregulatory Center

The PNS and the SNS

What part do the PNS and SNS play?

The PNS slows FHR and the SNS increases FHR, these two systems are constantly playing tug-of-war, causing variability, which tells us that the baby is getting enough oxygen for the systems to work properly

What role does hypoxemia play in fetal injury

Cell and organ function is intact

Enhanced oxygen uptake from blood

May cause decreased fetal movement and mild FHR changes

Can persist for days to weeks without injury

Could be due to placental insufficiency, or secondary to HTN/GDM

What role does Hypoxia play in fetal injury

Takes hours to cause injury; Stress hormones surge causing peripheral vasoconstriction which shunts blood to the brain, heart, and adrenals

Anerobic metabolism begins in peripheral tissues —> lactic acid accumulates

What role does Metabolic Acidosis play in fetal injury

Accumulation of lactic acid in the blood (Metabolic Acidemia) leads to the overwhelming of the bicarbonate buffer system, which decreases pH and impairs organ function

What role does Asphyxia play in fetal injury

Takes minutes to develop; Anerobic metabolism in heart and brain, glycogen stores depleted, major organ failure, potential injury for permanent injury

Can be caused by cord compression/prolapse

How is labor a physiological stressor

Contractions reduce blood flow by compressing the intervillous space, temporarily reducing gas exchange

What pH is considered acidic in the blood

Less than 7.15

VEAL CHOP MINE

Variable Deceleration —> Cord Compression —> Move position

Early Deceleration —> Head compression —> Intervention not needed

Acceleration —> Okay —> No intervention

Late Deceleration —> Placental insufficiency —> Evaluate for why

Acronym for interpreting FHR strips

DR - Determine risk factors

C - Contractions

BRA - Baseline Rate

V - Variability

A - Accelerations

D - Decelerations

O - Overall Assessment (Category 1, 2, 3)

Terminal Bradycardia

FHR<100 bpm = Pathologic Cause (Category III)

Prolonged acceleration

2 minutes - 10 minutes

Acceleration or Deceleration lasting 10 minutes or longer

Baseline change

What do you do to induce an acceleration

Fetal Scalp stimulation

What is the acme

The peak of a contraction

What is the nadir

The trough of a deceleration

What causes early deceleration, what are its parameters, and what is the intervention

Fetal head compression during contractions

Gradual onset to nadir lasting 30 seconds or greater

Acme and Nadir occur at the same time, the deceleration mirrors the contraction

Rarely drops below 100 bpm

No intervention needed - benign

What causes variable deceleration, what are its parameters, and what is the intervention

Umbilical cord compression reduces blood flow, reducing FHR

Abrupt onset to nadir less than 30 seconds

Drop in FHR by at least 15 bpm for at least 15 seconds, at most 2 minutes

Variable in shape. timing, and depth - can occur with/without contractions

Rapid return to baseline; may have “shoulders” characteristic

Intervention: Reposition mom

What is a simple variable deceleration

A variable deceleration that’s less than 60 seconds, the nadir is greater than or at 60 bpm, and has quick return - generally tolerable

What is a prolonged/deep variable deceleration

A variable deceleration that’s greater than 60 seconds or the nadir is less than 60 bpm - concerning

What causes late deceleration, what are its parameters, and what is the intervention

Uteroplacental insufficiency caused by contractions reducing gas exchange greater than normal

Gradual onset to nadir lasting 30 seconds or more

Begins after contractions start; Nadir occurs after Acme

Returns to baseline after contraction stops

Often shallow (10-20) bpm

Intrauterine Resuscitation, identifying the cause and treating it, possible delivery

Recurrent variable/late decelerations

Decelerations that occur for at least 50% of contractions

Category III if coupled with absent variability

What causes prolonged deceleration, what are its parameters, and what is the intervention

Cord prolapse, Uterine Rupture, Placental abruption, Maternal hypotension, Rapid fetal descent, Tachysystole, Terminal bradycardia

FHR decrease of at least 15 bpm for at least 2 minutes but less than 10 minutes

Intrauterine Resuscitation immedietly

Assess for prolapse or rapid descent

Assess maternal vitals

If no improvement with IUR —> emergent delivery

Intrauterine Resuscitation

1) Stop oxytocin (IF IT IS ON)

2) Reposition mother

3) IV fluid bolus

4) Nonrebreather at 10/15ml/hr

5) Start tocolytics (terbutaline 0.25 mg SQ)

6) Vaginal exam for prolapse/rapid descent/abruption

7) Expedite delivery if doesn’t work

Category I Criteria

a) Normal baseline FHR

b) Moderate Variability

c) No late or variable decelerations

d) Early decelerations may/may not be present

e) Accelerations may/may not be present

Category I Management

No intervention required

Continue routine monitoring

Document

Reassess per protocol

Category III Criteria

1a) Sinusoidal pattern

1b) Undulating baseline every 3-5 minutes for 20 minutes or more

1c) Not responsive to fetal scalp stimulation

OR

2a) Absent variability with either variable or late decelerations or bradycardia

OR

3a) Terminal Bradycardia

Category III Management

Immediate IUR, notify provider STAT, expedite delivery if IUR fails

What classifies as Category II and what is the management

Anything that is not category I and III

The management is to reevaluate and decided if an intervention is necessary

Could result in IUR, always notify provider