Mod VII: Placental Transfer & Fetal Exposure to Anesthetic Agents + Intrapartum Fetal Assessment:Biophysical & Biochemical Monitoring

Question 1

_{Placental Transfer & Fetal Exposure to Anesthetic Agents}

Which characteristics of most anesthetic drugs promote readily crossing of the placenta?

Answer 1

Low molecular weight

High lipid solubility

Relatively unionized

Minimally protein bound

_{[This applies to opioids, local anesthetics, inhalational agents]}

Question 2

_{Placental Transfer & Fetal Exposure to Anesthetic Agents}

​Rapid transfer of inhalational agents results in detectable arterial and venous concentrations in the fetus after just:

Answer 2

1 minute

Question 3

_{Placental Transfer & Fetal Exposure to Anesthetic Agents}

Which characteristics of Muscle relaxants prevents them from crossing the placenta?

Answer 3

Water soluble

Ionized

High molecular weights

Question 4

_{Placental Transfer & Fetal Exposure to Anesthetic Agents}

Damage to placenta (PIH, pre-eclampsia, DM) may lead to loss of placental capillary integrity - What could this lead to as far transfer across the placenta?

Answer 4

Nonselective transfer of materials across placenta

Trapping of ionized drugs with fetal acidosis and low pH

Question 5

_{Intrapartum Fetal Assessment - Biophysical & Biochemical Monitoring}

How does Fetal Heart Monitor (Biophysical) occur?

Answer 5

Two-channel recorder of FHR and uterine activity

(Can occur through a Direct or Indirect system)

Question 6

_{Fetal Heart Monitor (Biophysical)}

What are important considerations reguarding the _Direct Fetal Heart Monito_r (Biophysical) system?

Answer 6

Fetal ECG electrode

^{Fetal ECG electrode attached to presenting part}

IntraUterine Pressure (IUP)

^{measured with transducer connected to saline-filled catheter inserted transcervically}

Gives good Quantitative data

Require rupture of membrane and cervical dilation (1.5 cm)

_{[Break it down later!!!]}

Question 7

_{Fetal Heart Monitor (Biophysical)}

What’s the Most commonly used Fetal Heart Monitor (Biophysical) system?

Answer 7

Indirect Fetal Heart Monitor (Biophysical) system

Question 8

_{Fetal Heart Monitor (Biophysical)}

During Indirect Fetal Heart Monitoring, how is the Transducer secured to abdomen?

Answer 8

by velcro straps

Question 9

_{Fetal Heart Monitor (Biophysical)}

During Indirect Fetal Heart Monitoring, which technique is used to measure fetal heart rate (FHR)?

Answer 9

Ultrasound cardiography

Question 10

_{Fetal Heart Monitor (Biophysical)}

During Indirect Fetal Heart Monitoring, what instrument monitors uterine activity

Answer 10

Tocodynamometer

Question 11

_{Fetal Heart Monitor (Biophysical)}

Which types of data does Indirect Fetal Heart Monitoring give?

Answer 11

Qualitative data

Question 12

_{Fetal Heart Monitor (Biophysical)}

T/F: Indirect Fetal Heart monitoring does not require rupture of membranes or cervical dilation

Answer 12

True

All done externally on the skin

Question 13

_{Fetal Heart Monitor (Biophysical)}

What Parameters are evaluated via Fetal Heart Monitor?

Answer 13

Baseline heart rate

Baseline variability

Relationship of the heart rate to the uterine contraction

Question 14

_{Baseline Fetal Heart Rate}

What’s the normal Baseline Fetal Heart Rate?

Answer 14

110 to 160 beats/min

^{(Note the wide range!!!)}

Question 15

_{Baseline Fetal Heart Rate}

Which conditions may increased baseline fetal HR (tachycardia)?

Answer 15

Mild fetal hypoxia

Maternal fever

Chorioamnionitis

Administration of drugs (ephedrine/atropine)

Prematurity

Question 16

_{Baseline Fetal Heart Rate}

Which conditions may decrease baseline fetal HR (bradycardia)?

Answer 16

Fetal asphyxia/acidosis

Congenital heart block

Post-term pregnancy (>40 weeks)

Question 17

_{Baseline Fetal Heart Rate}

The Periodic ↑ in heart rate > 15 bpm lasting > 15 sec’s are also known as:

Answer 17

Accelerations

These are Normal response to fetal stimulation

^{(from vaginal exam, fetal capillary blood sampling)}

Accelerations are “Reassuring” in the overall condition of the fetus

Question 18

_{Intrapartum Fetal Assessment - Biophysical & Biochemical Monitoring}

The heart variability that reflects beat-to-beat adjustments of a normal fetal ANS is also known as:

Answer 18

Fetal Heart Rate Variability

Fetal Heart Rate Variability is Normally present

Question 19

_{Fetal Heart Rate Variability}

Which conditions or drugs could cause Loss of variability (smooth FHR tracing)?

Answer 19

Asphyxia → fetal CNS depression

Anencephaly

CNS depressant drugs

Parasympatholytics (atropine)

Question 20

_{Fetal Heart Rate Variability}

T/F: Loss of variability (smooth FHR tracing) is considered an ominous finding?

Answer 20

True

Question 21

_{Fetal Heart Rate Variability}

Which drug could cause increased Fetal Heart Rate Variability?

Answer 21

Ephedrine

Question 22

_{Intrapartum Fetal Assessment - Biophysical & Biochemical Monitoring}

Loss of both baseline variability and acceleration is “nonreassuring” - Why?

Answer 22

Represents fetal compromise!!!

Question 23

_{Fetal Heart Rate Patterns}

Periodic decelerations or accelerations occur in association with:

Answer 23

Uterine contractions

Question 24

_{Fetal Heart Rate Patterns}

What are the 3 major forms FHR decelerations?

Answer 24

Early - Late - Variable

Question 25

_{Fetal Heart Rate Patterns} What's the shape of _Early Decelerations_?

Answer 25

**U-shaped**

Question 26

_{Fetal Heart Rate Patterns} T/F: With Early Decelerations, HR decrases to less than 100 bpm

Answer 26

**False** HR does not decrease to \< 100 beats/min (it decreases by 10 – 40 bpm) Baby’s HR stays within normal limits of 110-160 bpm

Question 27

_{Fetal Heart Rate Patterns} With Early Decelerations, HR slows with onset of contraction - the low point of the decel corresponds to which aspect of the contraction?

Answer 27

**Peak of contraction** HR rises back up to baseline with uterine relaxation

Question 28

_{Fetal Heart Rate Patterns} What's the Etiology of Early Decelerations?

Answer 28

**Fetal head compression** (d/t fetal head being ingaged in the pelvis causing increased vagal tone)

Question 29

_{Fetal Heart Rate Patterns} T/F: Early Decelerations are Transient & well tolerated (no systemic hypoxia)

Answer 29

**True**

Question 30

_{Fetal Heart Rate Patterns} T/F: Adminstration of O2 corrects Early Decelerations

Answer 30

**False** O2 does not correct Early Decelerations

Question 31

_{Fetal Heart Rate Patterns} T/F: Atropine will block Early Decelerations

Answer 31

**True**

Question 32

_{Fetal Heart Rate Patterns} T/F: Early Decelerations are alarming

Answer 32

**False** Early Decelerations are _Non-alarming_ Baby’s HR mirrors moms contraction

Question 33

_{Fetal Heart Rate Patterns} Graphical representation of Early Decelerations

Answer 33

Note how the "early onset" of the deceleration mirrors the beginning of the contraction

Question 34

_{Fetal Heart Rate Patterns} What's the shape of Late Decelerations?

Answer 34

**U-shaped**

Question 35

_{Fetal Heart Rate Patterns} What's the timing of Late Decelerations in reference to uterine contraction?

Answer 35

Begin 20-30 sec's after onset of contraction

Question 36

_{Fetal Heart Rate Patterns} Where does the low point of Late Decelerations occur in reference to uterine contraction?

Answer 36

well **afte**r peak of contraction

Question 37

_{Fetal Heart Rate Patterns} What's the etiology of Late Decelerations?

Answer 37

**Utero-Placental insufficiency** Leading to fetal hypoxia

Question 38

_{Fetal Heart Rate Patterns} What are initial Treatment measures for Late Decelerations?

Answer 38

Improve fetal oxygenation O2 administration Correct maternal hypotension or aortocaval compression Reduce uterine activity ^{(stop pitocin, stop the contractions)}

Question 39

_{Fetal Heart Rate Patterns} What's the Treatment for repetitive Late Decelerations, a/w continuous, progressive fetal acidosis?

Answer 39

**Emergent delivery**

Question 40

_{Fetal Heart Rate Patterns} What are Key Points for Late Decelerations?

Answer 40

**NOT good!!!** Baby’s HR goes down long after the beginning of mom’s contraction and recovers way after the contraction is over Late Decelerations are caused by Uteroplacental insufficiency/fetal hypoxia

Question 41

_{Fetal Heart Rate Patterns} Graphical representation of Late Decelerations

Answer 41

Note the begining of the the uterine contraction at the bottom And the late descent of the fetal heart rate at the top fetal HR descent comes after the UC, and the rebound occurs way after the end of the contraction

Question 42

_{Fetal Heart Rate Patterns} The most common form of Decelerations which is variable in shape and onset, is a/w HR decrease \< 100 beats/min and/or increases \> 15 beats/min above baseline is also known as:

Answer 42

**Variable Decelerations**

Question 43

_{Fetal Heart Rate Patterns - Variable Decelerations} What's a common etiology of Variable Decelerations?

Answer 43

**Umbilical cord compression** after Rupture Of Membrane (ROM)

Question 44

_{Fetal Heart Rate Patterns - Variable Decelerations} What's the characteristic of initial changes a/w Variable Decelerations?

Answer 44

**Reflexive**

Question 45

_{Fetal Heart Rate Patterns - Variable Decelerations} What could ensue if compression a/w Variable Decelerations are frequent or prolonged?

Answer 45

**Fetal asphyxia**

Question 46

_{Fetal Heart Rate Patterns - Variable Decelerations} Fetal Heart Rate decrease that last more than 2mins are classified as:

Answer 46

**Prolonged Deceleration** Alarming!!!

Question 47

_{Fetal Heart Rate Patterns} Dips in the fetal heart tones that ook like V’s in shape are which types of Decelerations?

Answer 47

**Variable Decelerations**

Question 48

_{Fetal Heart Rate Patterns - Variable Decelerations} How is the fetal HR presents during Variable Decelerations?

Answer 48

**Majorly decreases** NOT good!

Question 49

_{Fetal Heart Rate Patterns - Variable Decelerations} What's a common etiology of Variable Decelerations?

Answer 49

Umbilical cord compression

Question 50

_{Fetal Heart Rate Patterns - Variable Decelerations} What's an appropriate intervention for Variable Decelerations?

Answer 50

Baby must be delivered immediately

Question 51

_{Fetal Heart Rate Patterns - Variable Decelerations} Graphical representation of Variable Decelerations

Answer 51

Note the dips in the fetal heart tones look like V’s

Question 52

_{Fetal Heart Rate Patterns} Graphical representation comparing the different Fetal Heart Rate Patterns

Answer 52

_{Fetal Heart Rate Patterns}

Question 53

_{Intrapartum Fetal Assessment - Biophysical & Biochemical Monitoring} What test may be performed to determine degree of fetal acidosis from hypoxia when abnormal FHR patterns cannot be corrected or significance is unclear?

Answer 53

**Fetal Scalp Blood pH** (Biochemical)

Question 54

_{Fetal Scalp Blood pH (Biochemical)} Which pH values on Fetal Scalp Blood pH are considered **lowest limit of normal**?

Answer 54

**pH \>7.25**

Question 55

_{Fetal Scalp Blood pH (Biochemical)} Which pH values on Fetal Scalp Blood pH are indicative of **pre-acidotic**? How must this situation be managed?

Answer 55

**pH 7.20 to 7.25** _FHR monitoring and repeated scalp blood sampling recommended_ ^{Treat to prevent further drop in pH It's up to the obstetrician if they want to deliver with pH in this range}

Question 56

_{Fetal Scalp Blood pH (Biochemical)} Which pH values on Fetal Scalp Blood pH are indicative of **fetal acidosis**? How must this situation be managed?

Answer 56

**pH \< 7.20** Requires _immediate delivery_

Question 57

_{Fetal Scalp Blood pH} T/F: Last predelivery fetal pH correlates with Apgar scores at 1 or 2 minutes

Answer 57

**True**

Question 58

_{Fetal Scalp Blood pH} What's the correlation btw pH immediately before delivery and infant condition?

Answer 58

Normal pH immediately before delivery assumes that infant will be in good condition

Question 59

_{Intrapartum Fetal Assessment - Biophysical & Biochemical Monitoring} What's the Newer technique to evaluate intrapartum fetal oxygenation?

Answer 59

**Fetal Pulse Oximetry** Remains adjunct to electronic FHR monitoring

Question 60

_{Fetal Pulse Oximetry} T/F: Remains adjunct to electronic FHR monitoring

Answer 60

**True** Both Fetal Pulse Oximetry + electronic FHR monitoring required

Question 61

_{Fetal Pulse Oximetry} What's Normal Fetal O2 saturation?

Answer 61

**30 - 70%**

Question 62

_{Fetal Pulse Oximetry} Which fetal O2 saturation values are indicative of **Fetal acidemia**?

Answer 62

**\< 30%** for *10 – 15mins*